From 85f2b08268c014e290b600ba49fa85530600eaa1 Mon Sep 17 00:00:00 2001 From: Tom Zanussi Date: Thu, 24 Oct 2013 08:59:24 -0500 Subject: tracing: Add basic event trigger framework Add a 'trigger' file for each trace event, enabling 'trace event triggers' to be set for trace events. 'trace event triggers' are patterned after the existing 'ftrace function triggers' implementation except that triggers are written to per-event 'trigger' files instead of to a single file such as the 'set_ftrace_filter' used for ftrace function triggers. The implementation is meant to be entirely separate from ftrace function triggers, in order to keep the respective implementations relatively simple and to allow them to diverge. The event trigger functionality is built on top of SOFT_DISABLE functionality. It adds a TRIGGER_MODE bit to the ftrace_event_file flags which is checked when any trace event fires. Triggers set for a particular event need to be checked regardless of whether that event is actually enabled or not - getting an event to fire even if it's not enabled is what's already implemented by SOFT_DISABLE mode, so trigger mode directly reuses that. Event trigger essentially inherit the soft disable logic in __ftrace_event_enable_disable() while adding a bit of logic and trigger reference counting via tm_ref on top of that in a new trace_event_trigger_enable_disable() function. Because the base __ftrace_event_enable_disable() code now needs to be invoked from outside trace_events.c, a wrapper is also added for those usages. The triggers for an event are actually invoked via a new function, event_triggers_call(), and code is also added to invoke them for ftrace_raw_event calls as well as syscall events. The main part of the patch creates a new trace_events_trigger.c file to contain the trace event triggers implementation. The standard open, read, and release file operations are implemented here. The open() implementation sets up for the various open modes of the 'trigger' file. It creates and attaches the trigger iterator and sets up the command parser. If opened for reading set up the trigger seq_ops. The read() implementation parses the event trigger written to the 'trigger' file, looks up the trigger command, and passes it along to that event_command's func() implementation for command-specific processing. The release() implementation does whatever cleanup is needed to release the 'trigger' file, like releasing the parser and trigger iterator, etc. A couple of functions for event command registration and unregistration are added, along with a list to add them to and a mutex to protect them, as well as an (initially empty) registration function to add the set of commands that will be added by future commits, and call to it from the trace event initialization code. also added are a couple trigger-specific data structures needed for these implementations such as a trigger iterator and a struct for trigger-specific data. A couple structs consisting mostly of function meant to be implemented in command-specific ways, event_command and event_trigger_ops, are used by the generic event trigger command implementations. They're being put into trace.h alongside the other trace_event data structures and functions, in the expectation that they'll be needed in several trace_event-related files such as trace_events_trigger.c and trace_events.c. The event_command.func() function is meant to be called by the trigger parsing code in order to add a trigger instance to the corresponding event. It essentially coordinates adding a live trigger instance to the event, and arming the triggering the event. Every event_command func() implementation essentially does the same thing for any command: - choose ops - use the value of param to choose either a number or count version of event_trigger_ops specific to the command - do the register or unregister of those ops - associate a filter, if specified, with the triggering event The reg() and unreg() ops allow command-specific implementations for event_trigger_op registration and unregistration, and the get_trigger_ops() op allows command-specific event_trigger_ops selection to be parameterized. When a trigger instance is added, the reg() op essentially adds that trigger to the triggering event and arms it, while unreg() does the opposite. The set_filter() function is used to associate a filter with the trigger - if the command doesn't specify a set_filter() implementation, the command will ignore filters. Each command has an associated trigger_type, which serves double duty, both as a unique identifier for the command as well as a value that can be used for setting a trigger mode bit during trigger invocation. The signature of func() adds a pointer to the event_command struct, used to invoke those functions, along with a command_data param that can be passed to the reg/unreg functions. This allows func() implementations to use command-specific blobs and supports code re-use. The event_trigger_ops.func() command corrsponds to the trigger 'probe' function that gets called when the triggering event is actually invoked. The other functions are used to list the trigger when needed, along with a couple mundane book-keeping functions. This also moves event_file_data() into trace.h so it can be used outside of trace_events.c. Link: http://lkml.kernel.org/r/316d95061accdee070aac8e5750afba0192fa5b9.1382622043.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi Idea-by: Steve Rostedt Signed-off-by: Steven Rostedt --- include/linux/ftrace_event.h | 11 +++++++++++ include/trace/ftrace.h | 4 ++++ 2 files changed, 15 insertions(+) (limited to 'include') diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index 8c9b7a1c4138..211e7ad2baf5 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -264,6 +264,7 @@ enum { FTRACE_EVENT_FL_NO_SET_FILTER_BIT, FTRACE_EVENT_FL_SOFT_MODE_BIT, FTRACE_EVENT_FL_SOFT_DISABLED_BIT, + FTRACE_EVENT_FL_TRIGGER_MODE_BIT, }; /* @@ -275,6 +276,7 @@ enum { * SOFT_MODE - The event is enabled/disabled by SOFT_DISABLED * SOFT_DISABLED - When set, do not trace the event (even though its * tracepoint may be enabled) + * TRIGGER_MODE - When set, invoke the triggers associated with the event */ enum { FTRACE_EVENT_FL_ENABLED = (1 << FTRACE_EVENT_FL_ENABLED_BIT), @@ -283,6 +285,7 @@ enum { FTRACE_EVENT_FL_NO_SET_FILTER = (1 << FTRACE_EVENT_FL_NO_SET_FILTER_BIT), FTRACE_EVENT_FL_SOFT_MODE = (1 << FTRACE_EVENT_FL_SOFT_MODE_BIT), FTRACE_EVENT_FL_SOFT_DISABLED = (1 << FTRACE_EVENT_FL_SOFT_DISABLED_BIT), + FTRACE_EVENT_FL_TRIGGER_MODE = (1 << FTRACE_EVENT_FL_TRIGGER_MODE_BIT), }; struct ftrace_event_file { @@ -292,6 +295,7 @@ struct ftrace_event_file { struct dentry *dir; struct trace_array *tr; struct ftrace_subsystem_dir *system; + struct list_head triggers; /* * 32 bit flags: @@ -299,6 +303,7 @@ struct ftrace_event_file { * bit 1: enabled cmd record * bit 2: enable/disable with the soft disable bit * bit 3: soft disabled + * bit 4: trigger enabled * * Note: The bits must be set atomically to prevent races * from other writers. Reads of flags do not need to be in @@ -310,6 +315,7 @@ struct ftrace_event_file { */ unsigned long flags; atomic_t sm_ref; /* soft-mode reference counter */ + atomic_t tm_ref; /* trigger-mode reference counter */ }; #define __TRACE_EVENT_FLAGS(name, value) \ @@ -337,6 +343,10 @@ struct ftrace_event_file { #define MAX_FILTER_STR_VAL 256 /* Should handle KSYM_SYMBOL_LEN */ +enum event_trigger_type { + ETT_NONE = (0), +}; + extern void destroy_preds(struct ftrace_event_file *file); extern void destroy_call_preds(struct ftrace_event_call *call); extern int filter_match_preds(struct event_filter *filter, void *rec); @@ -347,6 +357,7 @@ extern int filter_check_discard(struct ftrace_event_file *file, void *rec, extern int call_filter_check_discard(struct ftrace_event_call *call, void *rec, struct ring_buffer *buffer, struct ring_buffer_event *event); +extern void event_triggers_call(struct ftrace_event_file *file); enum { FILTER_OTHER = 0, diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index 5c38606613d8..0a48bff964bd 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -539,6 +539,10 @@ ftrace_raw_event_##call(void *__data, proto) \ int __data_size; \ int pc; \ \ + if (test_bit(FTRACE_EVENT_FL_TRIGGER_MODE_BIT, \ + &ftrace_file->flags)) \ + event_triggers_call(ftrace_file); \ + \ if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, \ &ftrace_file->flags)) \ return; \ -- cgit v1.2.3-70-g09d2 From 2a2df321158817811c5dc206dce808e0aa9f6d89 Mon Sep 17 00:00:00 2001 From: Tom Zanussi Date: Thu, 24 Oct 2013 08:59:25 -0500 Subject: tracing: Add 'traceon' and 'traceoff' event trigger commands Add 'traceon' and 'traceoff' event_command commands. traceon and traceoff event triggers are added by the user via these commands in a similar way and using practically the same syntax as the analagous 'traceon' and 'traceoff' ftrace function commands, but instead of writing to the set_ftrace_filter file, the traceon and traceoff triggers are written to the per-event 'trigger' files: echo 'traceon' > .../tracing/events/somesys/someevent/trigger echo 'traceoff' > .../tracing/events/somesys/someevent/trigger The above command will turn tracing on or off whenever someevent is hit. This also adds a 'count' version that limits the number of times the command will be invoked: echo 'traceon:N' > .../tracing/events/somesys/someevent/trigger echo 'traceoff:N' > .../tracing/events/somesys/someevent/trigger Where N is the number of times the command will be invoked. The above commands will will turn tracing on or off whenever someevent is hit, but only N times. Some common register/unregister_trigger() implementations of the event_command reg()/unreg() callbacks are also provided, which add and remove trigger instances to the per-event list of triggers, and arm/disarm them as appropriate. event_trigger_callback() is a general-purpose event_command func() implementation that orchestrates command parsing and registration for most normal commands. Most event commands will use these, but some will override and possibly reuse them. The event_trigger_init(), event_trigger_free(), and event_trigger_print() functions are meant to be common implementations of the event_trigger_ops init(), free(), and print() ops, respectively. Most trigger_ops implementations will use these, but some will override and possibly reuse them. Link: http://lkml.kernel.org/r/00a52816703b98d2072947478dd6e2d70cde5197.1382622043.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi Signed-off-by: Steven Rostedt --- include/linux/ftrace_event.h | 1 + kernel/trace/trace_events_trigger.c | 446 ++++++++++++++++++++++++++++++++++++ 2 files changed, 447 insertions(+) (limited to 'include') diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index 211e7ad2baf5..711c4dcfe8b7 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -345,6 +345,7 @@ struct ftrace_event_file { enum event_trigger_type { ETT_NONE = (0), + ETT_TRACE_ONOFF = (1 << 0), }; extern void destroy_preds(struct ftrace_event_file *file); diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c index 60a6a6d66dc0..4ea72ee169a7 100644 --- a/kernel/trace/trace_events_trigger.c +++ b/kernel/trace/trace_events_trigger.c @@ -28,6 +28,13 @@ static LIST_HEAD(trigger_commands); static DEFINE_MUTEX(trigger_cmd_mutex); +static void +trigger_data_free(struct event_trigger_data *data) +{ + synchronize_sched(); /* make sure current triggers exit before free */ + kfree(data); +} + /** * event_triggers_call - Call triggers associated with a trace event * @file: The ftrace_event_file associated with the event @@ -224,6 +231,129 @@ const struct file_operations event_trigger_fops = { .release = event_trigger_release, }; +/* + * Currently we only register event commands from __init, so mark this + * __init too. + */ +static __init int register_event_command(struct event_command *cmd) +{ + struct event_command *p; + int ret = 0; + + mutex_lock(&trigger_cmd_mutex); + list_for_each_entry(p, &trigger_commands, list) { + if (strcmp(cmd->name, p->name) == 0) { + ret = -EBUSY; + goto out_unlock; + } + } + list_add(&cmd->list, &trigger_commands); + out_unlock: + mutex_unlock(&trigger_cmd_mutex); + + return ret; +} + +/* + * Currently we only unregister event commands from __init, so mark + * this __init too. + */ +static __init int unregister_event_command(struct event_command *cmd) +{ + struct event_command *p, *n; + int ret = -ENODEV; + + mutex_lock(&trigger_cmd_mutex); + list_for_each_entry_safe(p, n, &trigger_commands, list) { + if (strcmp(cmd->name, p->name) == 0) { + ret = 0; + list_del_init(&p->list); + goto out_unlock; + } + } + out_unlock: + mutex_unlock(&trigger_cmd_mutex); + + return ret; +} + +/** + * event_trigger_print - Generic event_trigger_ops @print implementation + * @name: The name of the event trigger + * @m: The seq_file being printed to + * @data: Trigger-specific data + * @filter_str: filter_str to print, if present + * + * Common implementation for event triggers to print themselves. + * + * Usually wrapped by a function that simply sets the @name of the + * trigger command and then invokes this. + * + * Return: 0 on success, errno otherwise + */ +static int +event_trigger_print(const char *name, struct seq_file *m, + void *data, char *filter_str) +{ + long count = (long)data; + + seq_printf(m, "%s", name); + + if (count == -1) + seq_puts(m, ":unlimited"); + else + seq_printf(m, ":count=%ld", count); + + if (filter_str) + seq_printf(m, " if %s\n", filter_str); + else + seq_puts(m, "\n"); + + return 0; +} + +/** + * event_trigger_init - Generic event_trigger_ops @init implementation + * @ops: The trigger ops associated with the trigger + * @data: Trigger-specific data + * + * Common implementation of event trigger initialization. + * + * Usually used directly as the @init method in event trigger + * implementations. + * + * Return: 0 on success, errno otherwise + */ +static int +event_trigger_init(struct event_trigger_ops *ops, + struct event_trigger_data *data) +{ + data->ref++; + return 0; +} + +/** + * event_trigger_free - Generic event_trigger_ops @free implementation + * @ops: The trigger ops associated with the trigger + * @data: Trigger-specific data + * + * Common implementation of event trigger de-initialization. + * + * Usually used directly as the @free method in event trigger + * implementations. + */ +static void +event_trigger_free(struct event_trigger_ops *ops, + struct event_trigger_data *data) +{ + if (WARN_ON_ONCE(data->ref <= 0)) + return; + + data->ref--; + if (!data->ref) + trigger_data_free(data); +} + static int trace_event_trigger_enable_disable(struct ftrace_event_file *file, int trigger_enable) { @@ -272,7 +402,323 @@ clear_event_triggers(struct trace_array *tr) } } +/** + * register_trigger - Generic event_command @reg implementation + * @glob: The raw string used to register the trigger + * @ops: The trigger ops associated with the trigger + * @data: Trigger-specific data to associate with the trigger + * @file: The ftrace_event_file associated with the event + * + * Common implementation for event trigger registration. + * + * Usually used directly as the @reg method in event command + * implementations. + * + * Return: 0 on success, errno otherwise + */ +static int register_trigger(char *glob, struct event_trigger_ops *ops, + struct event_trigger_data *data, + struct ftrace_event_file *file) +{ + struct event_trigger_data *test; + int ret = 0; + + list_for_each_entry_rcu(test, &file->triggers, list) { + if (test->cmd_ops->trigger_type == data->cmd_ops->trigger_type) { + ret = -EEXIST; + goto out; + } + } + + if (data->ops->init) { + ret = data->ops->init(data->ops, data); + if (ret < 0) + goto out; + } + + list_add_rcu(&data->list, &file->triggers); + ret++; + + if (trace_event_trigger_enable_disable(file, 1) < 0) { + list_del_rcu(&data->list); + ret--; + } +out: + return ret; +} + +/** + * unregister_trigger - Generic event_command @unreg implementation + * @glob: The raw string used to register the trigger + * @ops: The trigger ops associated with the trigger + * @test: Trigger-specific data used to find the trigger to remove + * @file: The ftrace_event_file associated with the event + * + * Common implementation for event trigger unregistration. + * + * Usually used directly as the @unreg method in event command + * implementations. + */ +static void unregister_trigger(char *glob, struct event_trigger_ops *ops, + struct event_trigger_data *test, + struct ftrace_event_file *file) +{ + struct event_trigger_data *data; + bool unregistered = false; + + list_for_each_entry_rcu(data, &file->triggers, list) { + if (data->cmd_ops->trigger_type == test->cmd_ops->trigger_type) { + unregistered = true; + list_del_rcu(&data->list); + trace_event_trigger_enable_disable(file, 0); + break; + } + } + + if (unregistered && data->ops->free) + data->ops->free(data->ops, data); +} + +/** + * event_trigger_callback - Generic event_command @func implementation + * @cmd_ops: The command ops, used for trigger registration + * @file: The ftrace_event_file associated with the event + * @glob: The raw string used to register the trigger + * @cmd: The cmd portion of the string used to register the trigger + * @param: The params portion of the string used to register the trigger + * + * Common implementation for event command parsing and trigger + * instantiation. + * + * Usually used directly as the @func method in event command + * implementations. + * + * Return: 0 on success, errno otherwise + */ +static int +event_trigger_callback(struct event_command *cmd_ops, + struct ftrace_event_file *file, + char *glob, char *cmd, char *param) +{ + struct event_trigger_data *trigger_data; + struct event_trigger_ops *trigger_ops; + char *trigger = NULL; + char *number; + int ret; + + /* separate the trigger from the filter (t:n [if filter]) */ + if (param && isdigit(param[0])) + trigger = strsep(¶m, " \t"); + + trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger); + + ret = -ENOMEM; + trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL); + if (!trigger_data) + goto out; + + trigger_data->count = -1; + trigger_data->ops = trigger_ops; + trigger_data->cmd_ops = cmd_ops; + INIT_LIST_HEAD(&trigger_data->list); + + if (glob[0] == '!') { + cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file); + kfree(trigger_data); + ret = 0; + goto out; + } + + if (trigger) { + number = strsep(&trigger, ":"); + + ret = -EINVAL; + if (!strlen(number)) + goto out_free; + + /* + * We use the callback data field (which is a pointer) + * as our counter. + */ + ret = kstrtoul(number, 0, &trigger_data->count); + if (ret) + goto out_free; + } + + if (!param) /* if param is non-empty, it's supposed to be a filter */ + goto out_reg; + + if (!cmd_ops->set_filter) + goto out_reg; + + ret = cmd_ops->set_filter(param, trigger_data, file); + if (ret < 0) + goto out_free; + + out_reg: + ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file); + /* + * The above returns on success the # of functions enabled, + * but if it didn't find any functions it returns zero. + * Consider no functions a failure too. + */ + if (!ret) { + ret = -ENOENT; + goto out_free; + } else if (ret < 0) + goto out_free; + ret = 0; + out: + return ret; + + out_free: + kfree(trigger_data); + goto out; +} + +static void +traceon_trigger(struct event_trigger_data *data) +{ + if (tracing_is_on()) + return; + + tracing_on(); +} + +static void +traceon_count_trigger(struct event_trigger_data *data) +{ + if (!data->count) + return; + + if (data->count != -1) + (data->count)--; + + traceon_trigger(data); +} + +static void +traceoff_trigger(struct event_trigger_data *data) +{ + if (!tracing_is_on()) + return; + + tracing_off(); +} + +static void +traceoff_count_trigger(struct event_trigger_data *data) +{ + if (!data->count) + return; + + if (data->count != -1) + (data->count)--; + + traceoff_trigger(data); +} + +static int +traceon_trigger_print(struct seq_file *m, struct event_trigger_ops *ops, + struct event_trigger_data *data) +{ + return event_trigger_print("traceon", m, (void *)data->count, + data->filter_str); +} + +static int +traceoff_trigger_print(struct seq_file *m, struct event_trigger_ops *ops, + struct event_trigger_data *data) +{ + return event_trigger_print("traceoff", m, (void *)data->count, + data->filter_str); +} + +static struct event_trigger_ops traceon_trigger_ops = { + .func = traceon_trigger, + .print = traceon_trigger_print, + .init = event_trigger_init, + .free = event_trigger_free, +}; + +static struct event_trigger_ops traceon_count_trigger_ops = { + .func = traceon_count_trigger, + .print = traceon_trigger_print, + .init = event_trigger_init, + .free = event_trigger_free, +}; + +static struct event_trigger_ops traceoff_trigger_ops = { + .func = traceoff_trigger, + .print = traceoff_trigger_print, + .init = event_trigger_init, + .free = event_trigger_free, +}; + +static struct event_trigger_ops traceoff_count_trigger_ops = { + .func = traceoff_count_trigger, + .print = traceoff_trigger_print, + .init = event_trigger_init, + .free = event_trigger_free, +}; + +static struct event_trigger_ops * +onoff_get_trigger_ops(char *cmd, char *param) +{ + struct event_trigger_ops *ops; + + /* we register both traceon and traceoff to this callback */ + if (strcmp(cmd, "traceon") == 0) + ops = param ? &traceon_count_trigger_ops : + &traceon_trigger_ops; + else + ops = param ? &traceoff_count_trigger_ops : + &traceoff_trigger_ops; + + return ops; +} + +static struct event_command trigger_traceon_cmd = { + .name = "traceon", + .trigger_type = ETT_TRACE_ONOFF, + .func = event_trigger_callback, + .reg = register_trigger, + .unreg = unregister_trigger, + .get_trigger_ops = onoff_get_trigger_ops, +}; + +static struct event_command trigger_traceoff_cmd = { + .name = "traceoff", + .trigger_type = ETT_TRACE_ONOFF, + .func = event_trigger_callback, + .reg = register_trigger, + .unreg = unregister_trigger, + .get_trigger_ops = onoff_get_trigger_ops, +}; + +static __init void unregister_trigger_traceon_traceoff_cmds(void) +{ + unregister_event_command(&trigger_traceon_cmd); + unregister_event_command(&trigger_traceoff_cmd); +} + +static __init int register_trigger_traceon_traceoff_cmds(void) +{ + int ret; + + ret = register_event_command(&trigger_traceon_cmd); + if (WARN_ON(ret < 0)) + return ret; + ret = register_event_command(&trigger_traceoff_cmd); + if (WARN_ON(ret < 0)) + unregister_trigger_traceon_traceoff_cmds(); + + return ret; +} + __init int register_trigger_cmds(void) { + register_trigger_traceon_traceoff_cmds(); + return 0; } -- cgit v1.2.3-70-g09d2 From 93e31ffbf417a84fbae518fb46b3ea3f0d8fa6e1 Mon Sep 17 00:00:00 2001 From: Tom Zanussi Date: Thu, 24 Oct 2013 08:59:26 -0500 Subject: tracing: Add 'snapshot' event trigger command Add 'snapshot' event_command. snapshot event triggers are added by the user via this command in a similar way and using practically the same syntax as the analogous 'snapshot' ftrace function command, but instead of writing to the set_ftrace_filter file, the snapshot event trigger is written to the per-event 'trigger' files: echo 'snapshot' > .../somesys/someevent/trigger The above command will turn on snapshots for someevent i.e. whenever someevent is hit, a snapshot will be done. This also adds a 'count' version that limits the number of times the command will be invoked: echo 'snapshot:N' > .../somesys/someevent/trigger Where N is the number of times the command will be invoked. The above command will snapshot N times for someevent i.e. whenever someevent is hit N times, a snapshot will be done. Also adds a new tracing_alloc_snapshot() function - the existing tracing_snapshot_alloc() function is a special version of tracing_snapshot() that also does the snapshot allocation - the snapshot triggers would like to be able to do just the allocation but not take a snapshot; the existing tracing_snapshot_alloc() in turn now also calls tracing_alloc_snapshot() underneath to do that allocation. Link: http://lkml.kernel.org/r/c9524dd07ce01f9dcbd59011290e0a8d5b47d7ad.1382622043.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi [ fix up from kbuild test robot --- include/linux/ftrace_event.h | 1 + kernel/trace/trace.c | 33 ++++++++++++-- kernel/trace/trace.h | 1 + kernel/trace/trace_events_trigger.c | 85 +++++++++++++++++++++++++++++++++++++ 4 files changed, 117 insertions(+), 3 deletions(-) (limited to 'include') diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index 711c4dcfe8b7..6efa8c2745b5 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -346,6 +346,7 @@ struct ftrace_event_file { enum event_trigger_type { ETT_NONE = (0), ETT_TRACE_ONOFF = (1 << 0), + ETT_SNAPSHOT = (1 << 1), }; extern void destroy_preds(struct ftrace_event_file *file); diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 9d20cd9743ef..59bf5b56ccc0 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -594,6 +594,28 @@ void free_snapshot(struct trace_array *tr) tr->allocated_snapshot = false; } +/** + * tracing_alloc_snapshot - allocate snapshot buffer. + * + * This only allocates the snapshot buffer if it isn't already + * allocated - it doesn't also take a snapshot. + * + * This is meant to be used in cases where the snapshot buffer needs + * to be set up for events that can't sleep but need to be able to + * trigger a snapshot. + */ +int tracing_alloc_snapshot(void) +{ + struct trace_array *tr = &global_trace; + int ret; + + ret = alloc_snapshot(tr); + WARN_ON(ret < 0); + + return ret; +} +EXPORT_SYMBOL_GPL(tracing_alloc_snapshot); + /** * trace_snapshot_alloc - allocate and take a snapshot of the current buffer. * @@ -607,11 +629,10 @@ void free_snapshot(struct trace_array *tr) */ void tracing_snapshot_alloc(void) { - struct trace_array *tr = &global_trace; int ret; - ret = alloc_snapshot(tr); - if (WARN_ON(ret < 0)) + ret = tracing_alloc_snapshot(); + if (ret < 0) return; tracing_snapshot(); @@ -623,6 +644,12 @@ void tracing_snapshot(void) WARN_ONCE(1, "Snapshot feature not enabled, but internal snapshot used"); } EXPORT_SYMBOL_GPL(tracing_snapshot); +int tracing_alloc_snapshot(void) +{ + WARN_ONCE(1, "Snapshot feature not enabled, but snapshot allocation used"); + return -ENODEV; +} +EXPORT_SYMBOL_GPL(tracing_alloc_snapshot); void tracing_snapshot_alloc(void) { /* Give warning */ diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 9775e518fe77..50723e5e2b3c 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1211,6 +1211,7 @@ struct event_command { extern int trace_event_enable_disable(struct ftrace_event_file *file, int enable, int soft_disable); +extern int tracing_alloc_snapshot(void); extern const char *__start___trace_bprintk_fmt[]; extern const char *__stop___trace_bprintk_fmt[]; diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c index 4ea72ee169a7..d775c3da180f 100644 --- a/kernel/trace/trace_events_trigger.c +++ b/kernel/trace/trace_events_trigger.c @@ -696,6 +696,90 @@ static struct event_command trigger_traceoff_cmd = { .get_trigger_ops = onoff_get_trigger_ops, }; +#ifdef CONFIG_TRACER_SNAPSHOT +static void +snapshot_trigger(struct event_trigger_data *data) +{ + tracing_snapshot(); +} + +static void +snapshot_count_trigger(struct event_trigger_data *data) +{ + if (!data->count) + return; + + if (data->count != -1) + (data->count)--; + + snapshot_trigger(data); +} + +static int +register_snapshot_trigger(char *glob, struct event_trigger_ops *ops, + struct event_trigger_data *data, + struct ftrace_event_file *file) +{ + int ret = register_trigger(glob, ops, data, file); + + if (ret > 0 && tracing_alloc_snapshot() != 0) { + unregister_trigger(glob, ops, data, file); + ret = 0; + } + + return ret; +} + +static int +snapshot_trigger_print(struct seq_file *m, struct event_trigger_ops *ops, + struct event_trigger_data *data) +{ + return event_trigger_print("snapshot", m, (void *)data->count, + data->filter_str); +} + +static struct event_trigger_ops snapshot_trigger_ops = { + .func = snapshot_trigger, + .print = snapshot_trigger_print, + .init = event_trigger_init, + .free = event_trigger_free, +}; + +static struct event_trigger_ops snapshot_count_trigger_ops = { + .func = snapshot_count_trigger, + .print = snapshot_trigger_print, + .init = event_trigger_init, + .free = event_trigger_free, +}; + +static struct event_trigger_ops * +snapshot_get_trigger_ops(char *cmd, char *param) +{ + return param ? &snapshot_count_trigger_ops : &snapshot_trigger_ops; +} + +static struct event_command trigger_snapshot_cmd = { + .name = "snapshot", + .trigger_type = ETT_SNAPSHOT, + .func = event_trigger_callback, + .reg = register_snapshot_trigger, + .unreg = unregister_trigger, + .get_trigger_ops = snapshot_get_trigger_ops, +}; + +static __init int register_trigger_snapshot_cmd(void) +{ + int ret; + + ret = register_event_command(&trigger_snapshot_cmd); + WARN_ON(ret < 0); + + return ret; +} +#else +static __init int register_trigger_snapshot_cmd(void) { return 0; } +#endif /* CONFIG_TRACER_SNAPSHOT */ + static __init void unregister_trigger_traceon_traceoff_cmds(void) { unregister_event_command(&trigger_traceon_cmd); @@ -719,6 +803,7 @@ static __init int register_trigger_traceon_traceoff_cmds(void) __init int register_trigger_cmds(void) { register_trigger_traceon_traceoff_cmds(); + register_trigger_snapshot_cmd(); return 0; } -- cgit v1.2.3-70-g09d2 From f21ecbb35f865a508073c0e73854da469a07f278 Mon Sep 17 00:00:00 2001 From: Tom Zanussi Date: Thu, 24 Oct 2013 08:59:27 -0500 Subject: tracing: Add 'stacktrace' event trigger command Add 'stacktrace' event_command. stacktrace event triggers are added by the user via this command in a similar way and using practically the same syntax as the analogous 'stacktrace' ftrace function command, but instead of writing to the set_ftrace_filter file, the stacktrace event trigger is written to the per-event 'trigger' files: echo 'stacktrace' > .../tracing/events/somesys/someevent/trigger The above command will turn on stacktraces for someevent i.e. whenever someevent is hit, a stacktrace will be logged. This also adds a 'count' version that limits the number of times the command will be invoked: echo 'stacktrace:N' > .../tracing/events/somesys/someevent/trigger Where N is the number of times the command will be invoked. The above command will log N stacktraces for someevent i.e. whenever someevent is hit N times, a stacktrace will be logged. Link: http://lkml.kernel.org/r/0c30c008a0828c660aa0e1bbd3255cf179ed5c30.1382622043.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi Signed-off-by: Steven Rostedt --- include/linux/ftrace_event.h | 1 + kernel/trace/trace_events_trigger.c | 79 +++++++++++++++++++++++++++++++++++++ 2 files changed, 80 insertions(+) (limited to 'include') diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index 6efa8c2745b5..65caee44b4a9 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -347,6 +347,7 @@ enum event_trigger_type { ETT_NONE = (0), ETT_TRACE_ONOFF = (1 << 0), ETT_SNAPSHOT = (1 << 1), + ETT_STACKTRACE = (1 << 2), }; extern void destroy_preds(struct ftrace_event_file *file); diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c index d775c3da180f..a3bd1da90c56 100644 --- a/kernel/trace/trace_events_trigger.c +++ b/kernel/trace/trace_events_trigger.c @@ -780,6 +780,84 @@ static __init int register_trigger_snapshot_cmd(void) static __init int register_trigger_snapshot_cmd(void) { return 0; } #endif /* CONFIG_TRACER_SNAPSHOT */ +#ifdef CONFIG_STACKTRACE +/* + * Skip 3: + * stacktrace_trigger() + * event_triggers_post_call() + * ftrace_raw_event_xxx() + */ +#define STACK_SKIP 3 + +static void +stacktrace_trigger(struct event_trigger_data *data) +{ + trace_dump_stack(STACK_SKIP); +} + +static void +stacktrace_count_trigger(struct event_trigger_data *data) +{ + if (!data->count) + return; + + if (data->count != -1) + (data->count)--; + + stacktrace_trigger(data); +} + +static int +stacktrace_trigger_print(struct seq_file *m, struct event_trigger_ops *ops, + struct event_trigger_data *data) +{ + return event_trigger_print("stacktrace", m, (void *)data->count, + data->filter_str); +} + +static struct event_trigger_ops stacktrace_trigger_ops = { + .func = stacktrace_trigger, + .print = stacktrace_trigger_print, + .init = event_trigger_init, + .free = event_trigger_free, +}; + +static struct event_trigger_ops stacktrace_count_trigger_ops = { + .func = stacktrace_count_trigger, + .print = stacktrace_trigger_print, + .init = event_trigger_init, + .free = event_trigger_free, +}; + +static struct event_trigger_ops * +stacktrace_get_trigger_ops(char *cmd, char *param) +{ + return param ? &stacktrace_count_trigger_ops : &stacktrace_trigger_ops; +} + +static struct event_command trigger_stacktrace_cmd = { + .name = "stacktrace", + .trigger_type = ETT_STACKTRACE, + .post_trigger = true, + .func = event_trigger_callback, + .reg = register_trigger, + .unreg = unregister_trigger, + .get_trigger_ops = stacktrace_get_trigger_ops, +}; + +static __init int register_trigger_stacktrace_cmd(void) +{ + int ret; + + ret = register_event_command(&trigger_stacktrace_cmd); + WARN_ON(ret < 0); + + return ret; +} +#else +static __init int register_trigger_stacktrace_cmd(void) { return 0; } +#endif /* CONFIG_STACKTRACE */ + static __init void unregister_trigger_traceon_traceoff_cmds(void) { unregister_event_command(&trigger_traceon_cmd); @@ -804,6 +882,7 @@ __init int register_trigger_cmds(void) { register_trigger_traceon_traceoff_cmds(); register_trigger_snapshot_cmd(); + register_trigger_stacktrace_cmd(); return 0; } -- cgit v1.2.3-70-g09d2 From 7862ad1846e994574cb47dc503cc2b1646ea6593 Mon Sep 17 00:00:00 2001 From: Tom Zanussi Date: Thu, 24 Oct 2013 08:59:28 -0500 Subject: tracing: Add 'enable_event' and 'disable_event' event trigger commands Add 'enable_event' and 'disable_event' event_command commands. enable_event and disable_event event triggers are added by the user via these commands in a similar way and using practically the same syntax as the analagous 'enable_event' and 'disable_event' ftrace function commands, but instead of writing to the set_ftrace_filter file, the enable_event and disable_event triggers are written to the per-event 'trigger' files: echo 'enable_event:system:event' > .../othersys/otherevent/trigger echo 'disable_event:system:event' > .../othersys/otherevent/trigger The above commands will enable or disable the 'system:event' trace events whenever the othersys:otherevent events are hit. This also adds a 'count' version that limits the number of times the command will be invoked: echo 'enable_event:system:event:N' > .../othersys/otherevent/trigger echo 'disable_event:system:event:N' > .../othersys/otherevent/trigger Where N is the number of times the command will be invoked. The above commands will will enable or disable the 'system:event' trace events whenever the othersys:otherevent events are hit, but only N times. This also makes the find_event_file() helper function extern, since it's useful to use from other places, such as the event triggers code, so make it accessible. Link: http://lkml.kernel.org/r/f825f3048c3f6b026ee37ae5825f9fc373451828.1382622043.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi Signed-off-by: Steven Rostedt --- include/linux/ftrace_event.h | 1 + kernel/trace/trace.h | 4 + kernel/trace/trace_events.c | 2 +- kernel/trace/trace_events_trigger.c | 359 ++++++++++++++++++++++++++++++++++++ 4 files changed, 365 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index 65caee44b4a9..2f73c3988fc7 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -348,6 +348,7 @@ enum event_trigger_type { ETT_TRACE_ONOFF = (1 << 0), ETT_SNAPSHOT = (1 << 1), ETT_STACKTRACE = (1 << 2), + ETT_EVENT_ENABLE = (1 << 3), }; extern void destroy_preds(struct ftrace_event_file *file); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 50723e5e2b3c..ccbd8104cf99 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1028,6 +1028,10 @@ extern void trace_event_enable_cmd_record(bool enable); extern int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr); extern int event_trace_del_tracer(struct trace_array *tr); +extern struct ftrace_event_file *find_event_file(struct trace_array *tr, + const char *system, + const char *event); + static inline void *event_file_data(struct file *filp) { return ACCESS_ONCE(file_inode(filp)->i_private); diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 442775c9dbf3..9a974bd843d4 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -1868,7 +1868,7 @@ struct event_probe_data { bool enable; }; -static struct ftrace_event_file * +struct ftrace_event_file * find_event_file(struct trace_array *tr, const char *system, const char *event) { struct ftrace_event_file *file; diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c index a3bd1da90c56..45e48b109d51 100644 --- a/kernel/trace/trace_events_trigger.c +++ b/kernel/trace/trace_events_trigger.c @@ -864,6 +864,364 @@ static __init void unregister_trigger_traceon_traceoff_cmds(void) unregister_event_command(&trigger_traceoff_cmd); } +/* Avoid typos */ +#define ENABLE_EVENT_STR "enable_event" +#define DISABLE_EVENT_STR "disable_event" + +struct enable_trigger_data { + struct ftrace_event_file *file; + bool enable; +}; + +static void +event_enable_trigger(struct event_trigger_data *data) +{ + struct enable_trigger_data *enable_data = data->private_data; + + if (enable_data->enable) + clear_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &enable_data->file->flags); + else + set_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &enable_data->file->flags); +} + +static void +event_enable_count_trigger(struct event_trigger_data *data) +{ + struct enable_trigger_data *enable_data = data->private_data; + + if (!data->count) + return; + + /* Skip if the event is in a state we want to switch to */ + if (enable_data->enable == !(enable_data->file->flags & FTRACE_EVENT_FL_SOFT_DISABLED)) + return; + + if (data->count != -1) + (data->count)--; + + event_enable_trigger(data); +} + +static int +event_enable_trigger_print(struct seq_file *m, struct event_trigger_ops *ops, + struct event_trigger_data *data) +{ + struct enable_trigger_data *enable_data = data->private_data; + + seq_printf(m, "%s:%s:%s", + enable_data->enable ? ENABLE_EVENT_STR : DISABLE_EVENT_STR, + enable_data->file->event_call->class->system, + enable_data->file->event_call->name); + + if (data->count == -1) + seq_puts(m, ":unlimited"); + else + seq_printf(m, ":count=%ld", data->count); + + if (data->filter_str) + seq_printf(m, " if %s\n", data->filter_str); + else + seq_puts(m, "\n"); + + return 0; +} + +static void +event_enable_trigger_free(struct event_trigger_ops *ops, + struct event_trigger_data *data) +{ + struct enable_trigger_data *enable_data = data->private_data; + + if (WARN_ON_ONCE(data->ref <= 0)) + return; + + data->ref--; + if (!data->ref) { + /* Remove the SOFT_MODE flag */ + trace_event_enable_disable(enable_data->file, 0, 1); + module_put(enable_data->file->event_call->mod); + trigger_data_free(data); + kfree(enable_data); + } +} + +static struct event_trigger_ops event_enable_trigger_ops = { + .func = event_enable_trigger, + .print = event_enable_trigger_print, + .init = event_trigger_init, + .free = event_enable_trigger_free, +}; + +static struct event_trigger_ops event_enable_count_trigger_ops = { + .func = event_enable_count_trigger, + .print = event_enable_trigger_print, + .init = event_trigger_init, + .free = event_enable_trigger_free, +}; + +static struct event_trigger_ops event_disable_trigger_ops = { + .func = event_enable_trigger, + .print = event_enable_trigger_print, + .init = event_trigger_init, + .free = event_enable_trigger_free, +}; + +static struct event_trigger_ops event_disable_count_trigger_ops = { + .func = event_enable_count_trigger, + .print = event_enable_trigger_print, + .init = event_trigger_init, + .free = event_enable_trigger_free, +}; + +static int +event_enable_trigger_func(struct event_command *cmd_ops, + struct ftrace_event_file *file, + char *glob, char *cmd, char *param) +{ + struct ftrace_event_file *event_enable_file; + struct enable_trigger_data *enable_data; + struct event_trigger_data *trigger_data; + struct event_trigger_ops *trigger_ops; + struct trace_array *tr = file->tr; + const char *system; + const char *event; + char *trigger; + char *number; + bool enable; + int ret; + + if (!param) + return -EINVAL; + + /* separate the trigger from the filter (s:e:n [if filter]) */ + trigger = strsep(¶m, " \t"); + if (!trigger) + return -EINVAL; + + system = strsep(&trigger, ":"); + if (!trigger) + return -EINVAL; + + event = strsep(&trigger, ":"); + + ret = -EINVAL; + event_enable_file = find_event_file(tr, system, event); + if (!event_enable_file) + goto out; + + enable = strcmp(cmd, ENABLE_EVENT_STR) == 0; + + trigger_ops = cmd_ops->get_trigger_ops(cmd, trigger); + + ret = -ENOMEM; + trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL); + if (!trigger_data) + goto out; + + enable_data = kzalloc(sizeof(*enable_data), GFP_KERNEL); + if (!enable_data) { + kfree(trigger_data); + goto out; + } + + trigger_data->count = -1; + trigger_data->ops = trigger_ops; + trigger_data->cmd_ops = cmd_ops; + INIT_LIST_HEAD(&trigger_data->list); + RCU_INIT_POINTER(trigger_data->filter, NULL); + + enable_data->enable = enable; + enable_data->file = event_enable_file; + trigger_data->private_data = enable_data; + + if (glob[0] == '!') { + cmd_ops->unreg(glob+1, trigger_ops, trigger_data, file); + kfree(trigger_data); + kfree(enable_data); + ret = 0; + goto out; + } + + if (trigger) { + number = strsep(&trigger, ":"); + + ret = -EINVAL; + if (!strlen(number)) + goto out_free; + + /* + * We use the callback data field (which is a pointer) + * as our counter. + */ + ret = kstrtoul(number, 0, &trigger_data->count); + if (ret) + goto out_free; + } + + if (!param) /* if param is non-empty, it's supposed to be a filter */ + goto out_reg; + + if (!cmd_ops->set_filter) + goto out_reg; + + ret = cmd_ops->set_filter(param, trigger_data, file); + if (ret < 0) + goto out_free; + + out_reg: + /* Don't let event modules unload while probe registered */ + ret = try_module_get(event_enable_file->event_call->mod); + if (!ret) { + ret = -EBUSY; + goto out_free; + } + + ret = trace_event_enable_disable(event_enable_file, 1, 1); + if (ret < 0) + goto out_put; + ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file); + /* + * The above returns on success the # of functions enabled, + * but if it didn't find any functions it returns zero. + * Consider no functions a failure too. + */ + if (!ret) { + ret = -ENOENT; + goto out_disable; + } else if (ret < 0) + goto out_disable; + /* Just return zero, not the number of enabled functions */ + ret = 0; + out: + return ret; + + out_disable: + trace_event_enable_disable(event_enable_file, 0, 1); + out_put: + module_put(event_enable_file->event_call->mod); + out_free: + kfree(trigger_data); + kfree(enable_data); + goto out; +} + +static int event_enable_register_trigger(char *glob, + struct event_trigger_ops *ops, + struct event_trigger_data *data, + struct ftrace_event_file *file) +{ + struct enable_trigger_data *enable_data = data->private_data; + struct enable_trigger_data *test_enable_data; + struct event_trigger_data *test; + int ret = 0; + + list_for_each_entry_rcu(test, &file->triggers, list) { + test_enable_data = test->private_data; + if (test_enable_data && + (test_enable_data->file == enable_data->file)) { + ret = -EEXIST; + goto out; + } + } + + if (data->ops->init) { + ret = data->ops->init(data->ops, data); + if (ret < 0) + goto out; + } + + list_add_rcu(&data->list, &file->triggers); + ret++; + + if (trace_event_trigger_enable_disable(file, 1) < 0) { + list_del_rcu(&data->list); + ret--; + } +out: + return ret; +} + +static void event_enable_unregister_trigger(char *glob, + struct event_trigger_ops *ops, + struct event_trigger_data *test, + struct ftrace_event_file *file) +{ + struct enable_trigger_data *test_enable_data = test->private_data; + struct enable_trigger_data *enable_data; + struct event_trigger_data *data; + bool unregistered = false; + + list_for_each_entry_rcu(data, &file->triggers, list) { + enable_data = data->private_data; + if (enable_data && + (enable_data->file == test_enable_data->file)) { + unregistered = true; + list_del_rcu(&data->list); + trace_event_trigger_enable_disable(file, 0); + break; + } + } + + if (unregistered && data->ops->free) + data->ops->free(data->ops, data); +} + +static struct event_trigger_ops * +event_enable_get_trigger_ops(char *cmd, char *param) +{ + struct event_trigger_ops *ops; + bool enable; + + enable = strcmp(cmd, ENABLE_EVENT_STR) == 0; + + if (enable) + ops = param ? &event_enable_count_trigger_ops : + &event_enable_trigger_ops; + else + ops = param ? &event_disable_count_trigger_ops : + &event_disable_trigger_ops; + + return ops; +} + +static struct event_command trigger_enable_cmd = { + .name = ENABLE_EVENT_STR, + .trigger_type = ETT_EVENT_ENABLE, + .func = event_enable_trigger_func, + .reg = event_enable_register_trigger, + .unreg = event_enable_unregister_trigger, + .get_trigger_ops = event_enable_get_trigger_ops, +}; + +static struct event_command trigger_disable_cmd = { + .name = DISABLE_EVENT_STR, + .trigger_type = ETT_EVENT_ENABLE, + .func = event_enable_trigger_func, + .reg = event_enable_register_trigger, + .unreg = event_enable_unregister_trigger, + .get_trigger_ops = event_enable_get_trigger_ops, +}; + +static __init void unregister_trigger_enable_disable_cmds(void) +{ + unregister_event_command(&trigger_enable_cmd); + unregister_event_command(&trigger_disable_cmd); +} + +static __init int register_trigger_enable_disable_cmds(void) +{ + int ret; + + ret = register_event_command(&trigger_enable_cmd); + if (WARN_ON(ret < 0)) + return ret; + ret = register_event_command(&trigger_disable_cmd); + if (WARN_ON(ret < 0)) + unregister_trigger_enable_disable_cmds(); + + return ret; +} + static __init int register_trigger_traceon_traceoff_cmds(void) { int ret; @@ -883,6 +1241,7 @@ __init int register_trigger_cmds(void) register_trigger_traceon_traceoff_cmds(); register_trigger_snapshot_cmd(); register_trigger_stacktrace_cmd(); + register_trigger_enable_disable_cmds(); return 0; } -- cgit v1.2.3-70-g09d2 From bac5fb97a173aeef8296b3efdb552e3489d55179 Mon Sep 17 00:00:00 2001 From: Tom Zanussi Date: Thu, 24 Oct 2013 08:59:29 -0500 Subject: tracing: Add and use generic set_trigger_filter() implementation Add a generic event_command.set_trigger_filter() op implementation and have the current set of trigger commands use it - this essentially gives them all support for filters. Syntactically, filters are supported by adding 'if ' just after the command, in which case only events matching the filter will invoke the trigger. For example, to add a filter to an enable/disable_event command: echo 'enable_event:system:event if common_pid == 999' > \ .../othersys/otherevent/trigger The above command will only enable the system:event event if the common_pid field in the othersys:otherevent event is 999. As another example, to add a filter to a stacktrace command: echo 'stacktrace if common_pid == 999' > \ .../somesys/someevent/trigger The above command will only trigger a stacktrace if the common_pid field in the event is 999. The filter syntax is the same as that described in the 'Event filtering' section of Documentation/trace/events.txt. Because triggers can now use filters, the trigger-invoking logic needs to be moved in those cases - e.g. for ftrace_raw_event_calls, if a trigger has a filter associated with it, the trigger invocation now needs to happen after the { assign; } part of the call, in order for the trigger condition to be tested. There's still a SOFT_DISABLED-only check at the top of e.g. the ftrace_raw_events function, so when an event is soft disabled but not because of the presence of a trigger, the original SOFT_DISABLED behavior remains unchanged. There's also a bit of trickiness in that some triggers need to avoid being invoked while an event is currently in the process of being logged, since the trigger may itself log data into the trace buffer. Thus we make sure the current event is committed before invoking those triggers. To do that, we split the trigger invocation in two - the first part (event_triggers_call()) checks the filter using the current trace record; if a command has the post_trigger flag set, it sets a bit for itself in the return value, otherwise it directly invoks the trigger. Once all commands have been either invoked or set their return flag, event_triggers_call() returns. The current record is then either committed or discarded; if any commands have deferred their triggers, those commands are finally invoked following the close of the current event by event_triggers_post_call(). To simplify the above and make it more efficient, the TRIGGER_COND bit is introduced, which is set only if a soft-disabled trigger needs to use the log record for filter testing or needs to wait until the current log record is closed. The syscall event invocation code is also changed in analogous ways. Because event triggers need to be able to create and free filters, this also adds a couple external wrappers for the existing create_filter and free_filter functions, which are too generic to be made extern functions themselves. Link: http://lkml.kernel.org/r/7164930759d8719ef460357f143d995406e4eead.1382622043.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi Signed-off-by: Steven Rostedt --- include/linux/ftrace_event.h | 9 +- include/trace/ftrace.h | 48 +++++++--- kernel/trace/trace.h | 5 ++ kernel/trace/trace_events_filter.c | 12 +++ kernel/trace/trace_events_trigger.c | 170 +++++++++++++++++++++++++++++++++++- kernel/trace/trace_syscalls.c | 46 +++++++--- 6 files changed, 263 insertions(+), 27 deletions(-) (limited to 'include') diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index 2f73c3988fc7..03d2db22ad0d 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -1,3 +1,4 @@ + #ifndef _LINUX_FTRACE_EVENT_H #define _LINUX_FTRACE_EVENT_H @@ -265,6 +266,7 @@ enum { FTRACE_EVENT_FL_SOFT_MODE_BIT, FTRACE_EVENT_FL_SOFT_DISABLED_BIT, FTRACE_EVENT_FL_TRIGGER_MODE_BIT, + FTRACE_EVENT_FL_TRIGGER_COND_BIT, }; /* @@ -277,6 +279,7 @@ enum { * SOFT_DISABLED - When set, do not trace the event (even though its * tracepoint may be enabled) * TRIGGER_MODE - When set, invoke the triggers associated with the event + * TRIGGER_COND - When set, one or more triggers has an associated filter */ enum { FTRACE_EVENT_FL_ENABLED = (1 << FTRACE_EVENT_FL_ENABLED_BIT), @@ -286,6 +289,7 @@ enum { FTRACE_EVENT_FL_SOFT_MODE = (1 << FTRACE_EVENT_FL_SOFT_MODE_BIT), FTRACE_EVENT_FL_SOFT_DISABLED = (1 << FTRACE_EVENT_FL_SOFT_DISABLED_BIT), FTRACE_EVENT_FL_TRIGGER_MODE = (1 << FTRACE_EVENT_FL_TRIGGER_MODE_BIT), + FTRACE_EVENT_FL_TRIGGER_COND = (1 << FTRACE_EVENT_FL_TRIGGER_COND_BIT), }; struct ftrace_event_file { @@ -361,7 +365,10 @@ extern int filter_check_discard(struct ftrace_event_file *file, void *rec, extern int call_filter_check_discard(struct ftrace_event_call *call, void *rec, struct ring_buffer *buffer, struct ring_buffer_event *event); -extern void event_triggers_call(struct ftrace_event_file *file); +extern enum event_trigger_type event_triggers_call(struct ftrace_event_file *file, + void *rec); +extern void event_triggers_post_call(struct ftrace_event_file *file, + enum event_trigger_type tt); enum { FILTER_OTHER = 0, diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index 0a48bff964bd..0962968b8b37 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -418,6 +418,8 @@ static inline notrace int ftrace_get_offsets_##call( \ * struct ftrace_event_file *ftrace_file = __data; * struct ftrace_event_call *event_call = ftrace_file->event_call; * struct ftrace_data_offsets_ __maybe_unused __data_offsets; + * unsigned long eflags = ftrace_file->flags; + * enum event_trigger_type __tt = ETT_NONE; * struct ring_buffer_event *event; * struct ftrace_raw_ *entry; <-- defined in stage 1 * struct ring_buffer *buffer; @@ -425,9 +427,12 @@ static inline notrace int ftrace_get_offsets_##call( \ * int __data_size; * int pc; * - * if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, - * &ftrace_file->flags)) - * return; + * if (!(eflags & FTRACE_EVENT_FL_TRIGGER_COND)) { + * if (eflags & FTRACE_EVENT_FL_TRIGGER_MODE) + * event_triggers_call(ftrace_file, NULL); + * if (eflags & FTRACE_EVENT_FL_SOFT_DISABLED) + * return; + * } * * local_save_flags(irq_flags); * pc = preempt_count(); @@ -445,8 +450,17 @@ static inline notrace int ftrace_get_offsets_##call( \ * { ; } <-- Here we assign the entries by the __field and * __array macros. * - * if (!filter_check_discard(ftrace_file, entry, buffer, event)) + * if (eflags & FTRACE_EVENT_FL_TRIGGER_COND) + * __tt = event_triggers_call(ftrace_file, entry); + * + * if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, + * &ftrace_file->flags)) + * ring_buffer_discard_commit(buffer, event); + * else if (!filter_check_discard(ftrace_file, entry, buffer, event)) * trace_buffer_unlock_commit(buffer, event, irq_flags, pc); + * + * if (__tt) + * event_triggers_post_call(ftrace_file, __tt); * } * * static struct trace_event ftrace_event_type_ = { @@ -532,6 +546,8 @@ ftrace_raw_event_##call(void *__data, proto) \ struct ftrace_event_file *ftrace_file = __data; \ struct ftrace_event_call *event_call = ftrace_file->event_call; \ struct ftrace_data_offsets_##call __maybe_unused __data_offsets;\ + unsigned long eflags = ftrace_file->flags; \ + enum event_trigger_type __tt = ETT_NONE; \ struct ring_buffer_event *event; \ struct ftrace_raw_##call *entry; \ struct ring_buffer *buffer; \ @@ -539,13 +555,12 @@ ftrace_raw_event_##call(void *__data, proto) \ int __data_size; \ int pc; \ \ - if (test_bit(FTRACE_EVENT_FL_TRIGGER_MODE_BIT, \ - &ftrace_file->flags)) \ - event_triggers_call(ftrace_file); \ - \ - if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, \ - &ftrace_file->flags)) \ - return; \ + if (!(eflags & FTRACE_EVENT_FL_TRIGGER_COND)) { \ + if (eflags & FTRACE_EVENT_FL_TRIGGER_MODE) \ + event_triggers_call(ftrace_file, NULL); \ + if (eflags & FTRACE_EVENT_FL_SOFT_DISABLED) \ + return; \ + } \ \ local_save_flags(irq_flags); \ pc = preempt_count(); \ @@ -564,8 +579,17 @@ ftrace_raw_event_##call(void *__data, proto) \ \ { assign; } \ \ - if (!filter_check_discard(ftrace_file, entry, buffer, event)) \ + if (eflags & FTRACE_EVENT_FL_TRIGGER_COND) \ + __tt = event_triggers_call(ftrace_file, entry); \ + \ + if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, \ + &ftrace_file->flags)) \ + ring_buffer_discard_commit(buffer, event); \ + else if (!filter_check_discard(ftrace_file, entry, buffer, event)) \ trace_buffer_unlock_commit(buffer, event, irq_flags, pc); \ + \ + if (__tt) \ + event_triggers_post_call(ftrace_file, __tt); \ } /* * The ftrace_test_probe is compiled out, it is only here as a build time check diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index ccbd8104cf99..433bfc5dd576 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1,3 +1,4 @@ + #ifndef _LINUX_KERNEL_TRACE_H #define _LINUX_KERNEL_TRACE_H @@ -1020,6 +1021,10 @@ extern int apply_subsystem_event_filter(struct ftrace_subsystem_dir *dir, extern void print_subsystem_event_filter(struct event_subsystem *system, struct trace_seq *s); extern int filter_assign_type(const char *type); +extern int create_event_filter(struct ftrace_event_call *call, + char *filter_str, bool set_str, + struct event_filter **filterp); +extern void free_event_filter(struct event_filter *filter); struct ftrace_event_field * trace_find_event_field(struct ftrace_event_call *call, char *name); diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 2468f56dc5db..8a8631926a07 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -799,6 +799,11 @@ static void __free_filter(struct event_filter *filter) kfree(filter); } +void free_event_filter(struct event_filter *filter) +{ + __free_filter(filter); +} + void destroy_call_preds(struct ftrace_event_call *call) { __free_filter(call->filter); @@ -1938,6 +1943,13 @@ static int create_filter(struct ftrace_event_call *call, return err; } +int create_event_filter(struct ftrace_event_call *call, + char *filter_str, bool set_str, + struct event_filter **filterp) +{ + return create_filter(call, filter_str, set_str, filterp); +} + /** * create_system_filter - create a filter for an event_subsystem * @system: event_subsystem to create a filter for diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c index 45e48b109d51..f5b3f780fda4 100644 --- a/kernel/trace/trace_events_trigger.c +++ b/kernel/trace/trace_events_trigger.c @@ -31,6 +31,9 @@ static DEFINE_MUTEX(trigger_cmd_mutex); static void trigger_data_free(struct event_trigger_data *data) { + if (data->cmd_ops->set_filter) + data->cmd_ops->set_filter(NULL, data, NULL); + synchronize_sched(); /* make sure current triggers exit before free */ kfree(data); } @@ -38,27 +41,78 @@ trigger_data_free(struct event_trigger_data *data) /** * event_triggers_call - Call triggers associated with a trace event * @file: The ftrace_event_file associated with the event + * @rec: The trace entry for the event, NULL for unconditional invocation * * For each trigger associated with an event, invoke the trigger - * function registered with the associated trigger command. + * function registered with the associated trigger command. If rec is + * non-NULL, it means that the trigger requires further processing and + * shouldn't be unconditionally invoked. If rec is non-NULL and the + * trigger has a filter associated with it, rec will checked against + * the filter and if the record matches the trigger will be invoked. + * If the trigger is a 'post_trigger', meaning it shouldn't be invoked + * in any case until the current event is written, the trigger + * function isn't invoked but the bit associated with the deferred + * trigger is set in the return value. + * + * Returns an enum event_trigger_type value containing a set bit for + * any trigger that should be deferred, ETT_NONE if nothing to defer. * * Called from tracepoint handlers (with rcu_read_lock_sched() held). * * Return: an enum event_trigger_type value containing a set bit for * any trigger that should be deferred, ETT_NONE if nothing to defer. */ -void event_triggers_call(struct ftrace_event_file *file) +enum event_trigger_type +event_triggers_call(struct ftrace_event_file *file, void *rec) { struct event_trigger_data *data; + enum event_trigger_type tt = ETT_NONE; if (list_empty(&file->triggers)) - return; + return tt; - list_for_each_entry_rcu(data, &file->triggers, list) + list_for_each_entry_rcu(data, &file->triggers, list) { + if (!rec) { + data->ops->func(data); + continue; + } + if (data->filter && !filter_match_preds(data->filter, rec)) + continue; + if (data->cmd_ops->post_trigger) { + tt |= data->cmd_ops->trigger_type; + continue; + } data->ops->func(data); + } + return tt; } EXPORT_SYMBOL_GPL(event_triggers_call); +/** + * event_triggers_post_call - Call 'post_triggers' for a trace event + * @file: The ftrace_event_file associated with the event + * @tt: enum event_trigger_type containing a set bit for each trigger to invoke + * + * For each trigger associated with an event, invoke the trigger + * function registered with the associated trigger command, if the + * corresponding bit is set in the tt enum passed into this function. + * See @event_triggers_call for details on how those bits are set. + * + * Called from tracepoint handlers (with rcu_read_lock_sched() held). + */ +void +event_triggers_post_call(struct ftrace_event_file *file, + enum event_trigger_type tt) +{ + struct event_trigger_data *data; + + list_for_each_entry_rcu(data, &file->triggers, list) { + if (data->cmd_ops->trigger_type & tt) + data->ops->func(data); + } +} +EXPORT_SYMBOL_GPL(event_triggers_post_call); + static void *trigger_next(struct seq_file *m, void *t, loff_t *pos) { struct ftrace_event_file *event_file = event_file_data(m->private); @@ -402,6 +456,34 @@ clear_event_triggers(struct trace_array *tr) } } +/** + * update_cond_flag - Set or reset the TRIGGER_COND bit + * @file: The ftrace_event_file associated with the event + * + * If an event has triggers and any of those triggers has a filter or + * a post_trigger, trigger invocation needs to be deferred until after + * the current event has logged its data, and the event should have + * its TRIGGER_COND bit set, otherwise the TRIGGER_COND bit should be + * cleared. + */ +static void update_cond_flag(struct ftrace_event_file *file) +{ + struct event_trigger_data *data; + bool set_cond = false; + + list_for_each_entry_rcu(data, &file->triggers, list) { + if (data->filter || data->cmd_ops->post_trigger) { + set_cond = true; + break; + } + } + + if (set_cond) + set_bit(FTRACE_EVENT_FL_TRIGGER_COND_BIT, &file->flags); + else + clear_bit(FTRACE_EVENT_FL_TRIGGER_COND_BIT, &file->flags); +} + /** * register_trigger - Generic event_command @reg implementation * @glob: The raw string used to register the trigger @@ -443,6 +525,7 @@ static int register_trigger(char *glob, struct event_trigger_ops *ops, list_del_rcu(&data->list); ret--; } + update_cond_flag(file); out: return ret; } @@ -470,6 +553,7 @@ static void unregister_trigger(char *glob, struct event_trigger_ops *ops, if (data->cmd_ops->trigger_type == test->cmd_ops->trigger_type) { unregistered = true; list_del_rcu(&data->list); + update_cond_flag(file); trace_event_trigger_enable_disable(file, 0); break; } @@ -572,10 +656,78 @@ event_trigger_callback(struct event_command *cmd_ops, return ret; out_free: + if (cmd_ops->set_filter) + cmd_ops->set_filter(NULL, trigger_data, NULL); kfree(trigger_data); goto out; } +/** + * set_trigger_filter - Generic event_command @set_filter implementation + * @filter_str: The filter string for the trigger, NULL to remove filter + * @trigger_data: Trigger-specific data + * @file: The ftrace_event_file associated with the event + * + * Common implementation for event command filter parsing and filter + * instantiation. + * + * Usually used directly as the @set_filter method in event command + * implementations. + * + * Also used to remove a filter (if filter_str = NULL). + * + * Return: 0 on success, errno otherwise + */ +static int set_trigger_filter(char *filter_str, + struct event_trigger_data *trigger_data, + struct ftrace_event_file *file) +{ + struct event_trigger_data *data = trigger_data; + struct event_filter *filter = NULL, *tmp; + int ret = -EINVAL; + char *s; + + if (!filter_str) /* clear the current filter */ + goto assign; + + s = strsep(&filter_str, " \t"); + + if (!strlen(s) || strcmp(s, "if") != 0) + goto out; + + if (!filter_str) + goto out; + + /* The filter is for the 'trigger' event, not the triggered event */ + ret = create_event_filter(file->event_call, filter_str, false, &filter); + if (ret) + goto out; + assign: + tmp = data->filter; + + rcu_assign_pointer(data->filter, filter); + + if (tmp) { + /* Make sure the call is done with the filter */ + synchronize_sched(); + free_event_filter(tmp); + } + + kfree(data->filter_str); + data->filter_str = NULL; + + if (filter_str) { + data->filter_str = kstrdup(filter_str, GFP_KERNEL); + if (!data->filter_str) { + free_event_filter(data->filter); + data->filter = NULL; + ret = -ENOMEM; + } + } + out: + return ret; +} + static void traceon_trigger(struct event_trigger_data *data) { @@ -685,6 +837,7 @@ static struct event_command trigger_traceon_cmd = { .reg = register_trigger, .unreg = unregister_trigger, .get_trigger_ops = onoff_get_trigger_ops, + .set_filter = set_trigger_filter, }; static struct event_command trigger_traceoff_cmd = { @@ -694,6 +847,7 @@ static struct event_command trigger_traceoff_cmd = { .reg = register_trigger, .unreg = unregister_trigger, .get_trigger_ops = onoff_get_trigger_ops, + .set_filter = set_trigger_filter, }; #ifdef CONFIG_TRACER_SNAPSHOT @@ -765,6 +919,7 @@ static struct event_command trigger_snapshot_cmd = { .reg = register_snapshot_trigger, .unreg = unregister_trigger, .get_trigger_ops = snapshot_get_trigger_ops, + .set_filter = set_trigger_filter, }; static __init int register_trigger_snapshot_cmd(void) @@ -843,6 +998,7 @@ static struct event_command trigger_stacktrace_cmd = { .reg = register_trigger, .unreg = unregister_trigger, .get_trigger_ops = stacktrace_get_trigger_ops, + .set_filter = set_trigger_filter, }; static __init int register_trigger_stacktrace_cmd(void) @@ -1100,6 +1256,8 @@ event_enable_trigger_func(struct event_command *cmd_ops, out_put: module_put(event_enable_file->event_call->mod); out_free: + if (cmd_ops->set_filter) + cmd_ops->set_filter(NULL, trigger_data, NULL); kfree(trigger_data); kfree(enable_data); goto out; @@ -1137,6 +1295,7 @@ static int event_enable_register_trigger(char *glob, list_del_rcu(&data->list); ret--; } + update_cond_flag(file); out: return ret; } @@ -1157,6 +1316,7 @@ static void event_enable_unregister_trigger(char *glob, (enable_data->file == test_enable_data->file)) { unregistered = true; list_del_rcu(&data->list); + update_cond_flag(file); trace_event_trigger_enable_disable(file, 0); break; } @@ -1191,6 +1351,7 @@ static struct event_command trigger_enable_cmd = { .reg = event_enable_register_trigger, .unreg = event_enable_unregister_trigger, .get_trigger_ops = event_enable_get_trigger_ops, + .set_filter = set_trigger_filter, }; static struct event_command trigger_disable_cmd = { @@ -1200,6 +1361,7 @@ static struct event_command trigger_disable_cmd = { .reg = event_enable_register_trigger, .unreg = event_enable_unregister_trigger, .get_trigger_ops = event_enable_get_trigger_ops, + .set_filter = set_trigger_filter, }; static __init void unregister_trigger_enable_disable_cmds(void) diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index 936ec3960335..fdd955f2f1aa 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -306,8 +306,10 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id) struct syscall_trace_enter *entry; struct syscall_metadata *sys_data; struct ring_buffer_event *event; + enum event_trigger_type __tt = ETT_NONE; struct ring_buffer *buffer; unsigned long irq_flags; + unsigned long eflags; int pc; int syscall_nr; int size; @@ -321,10 +323,14 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id) if (!ftrace_file) return; - if (test_bit(FTRACE_EVENT_FL_TRIGGER_MODE_BIT, &ftrace_file->flags)) - event_triggers_call(ftrace_file); - if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags)) - return; + eflags = ftrace_file->flags; + + if (!(eflags & FTRACE_EVENT_FL_TRIGGER_COND)) { + if (eflags & FTRACE_EVENT_FL_TRIGGER_MODE) + event_triggers_call(ftrace_file, NULL); + if (eflags & FTRACE_EVENT_FL_SOFT_DISABLED) + return; + } sys_data = syscall_nr_to_meta(syscall_nr); if (!sys_data) @@ -345,9 +351,16 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id) entry->nr = syscall_nr; syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args); - if (!filter_check_discard(ftrace_file, entry, buffer, event)) + if (eflags & FTRACE_EVENT_FL_TRIGGER_COND) + __tt = event_triggers_call(ftrace_file, entry); + + if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags)) + ring_buffer_discard_commit(buffer, event); + else if (!filter_check_discard(ftrace_file, entry, buffer, event)) trace_current_buffer_unlock_commit(buffer, event, irq_flags, pc); + if (__tt) + event_triggers_post_call(ftrace_file, __tt); } static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret) @@ -357,8 +370,10 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret) struct syscall_trace_exit *entry; struct syscall_metadata *sys_data; struct ring_buffer_event *event; + enum event_trigger_type __tt = ETT_NONE; struct ring_buffer *buffer; unsigned long irq_flags; + unsigned long eflags; int pc; int syscall_nr; @@ -371,10 +386,14 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret) if (!ftrace_file) return; - if (test_bit(FTRACE_EVENT_FL_TRIGGER_MODE_BIT, &ftrace_file->flags)) - event_triggers_call(ftrace_file); - if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags)) - return; + eflags = ftrace_file->flags; + + if (!(eflags & FTRACE_EVENT_FL_TRIGGER_COND)) { + if (eflags & FTRACE_EVENT_FL_TRIGGER_MODE) + event_triggers_call(ftrace_file, NULL); + if (eflags & FTRACE_EVENT_FL_SOFT_DISABLED) + return; + } sys_data = syscall_nr_to_meta(syscall_nr); if (!sys_data) @@ -394,9 +413,16 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret) entry->nr = syscall_nr; entry->ret = syscall_get_return_value(current, regs); - if (!filter_check_discard(ftrace_file, entry, buffer, event)) + if (eflags & FTRACE_EVENT_FL_TRIGGER_COND) + __tt = event_triggers_call(ftrace_file, entry); + + if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags)) + ring_buffer_discard_commit(buffer, event); + else if (!filter_check_discard(ftrace_file, entry, buffer, event)) trace_current_buffer_unlock_commit(buffer, event, irq_flags, pc); + if (__tt) + event_triggers_post_call(ftrace_file, __tt); } static int reg_event_syscall_enter(struct ftrace_event_file *file, -- cgit v1.2.3-70-g09d2 From 098c879e1f2d6ee7afbfe959f6b04070065cec90 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Sat, 21 Dec 2013 17:39:40 -0500 Subject: tracing: Add generic tracing_lseek() function Trace event triggers added a lseek that uses the ftrace_filter_lseek() function. Unfortunately, when function tracing is not configured in that function is not defined and the kernel fails to build. This is the second time that function was added to a file ops and it broke the build due to requiring special config dependencies. Make a generic tracing_lseek() that all the tracing utilities may use. Also, modify the old ftrace_filter_lseek() to return 0 instead of 1 on WRONLY. Not sure why it was a 1 as that does not make sense. This also changes the old tracing_seek() to modify the file pos pointer on WRONLY as well. Reported-by: kbuild test robot Tested-by: Tom Zanussi Acked-by: Tom Zanussi Signed-off-by: Steven Rostedt --- include/linux/ftrace.h | 2 -- kernel/trace/ftrace.c | 25 ++++++------------------- kernel/trace/trace.c | 14 +++++++++----- kernel/trace/trace.h | 2 ++ kernel/trace/trace_events_trigger.c | 2 +- kernel/trace/trace_stack.c | 2 +- 6 files changed, 19 insertions(+), 28 deletions(-) (limited to 'include') diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 31ea4b428360..f4233b195dab 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -570,8 +570,6 @@ static inline int ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; } #endif /* CONFIG_DYNAMIC_FTRACE */ -loff_t ftrace_filter_lseek(struct file *file, loff_t offset, int whence); - /* totally disable ftrace - can not re-enable after this */ void ftrace_kill(void); diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 0e9f9eaade2f..531ffa6f5a7b 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1082,19 +1082,6 @@ static __init void ftrace_profile_debugfs(struct dentry *d_tracer) static struct pid * const ftrace_swapper_pid = &init_struct_pid; -loff_t -ftrace_filter_lseek(struct file *file, loff_t offset, int whence) -{ - loff_t ret; - - if (file->f_mode & FMODE_READ) - ret = seq_lseek(file, offset, whence); - else - file->f_pos = ret = 1; - - return ret; -} - #ifdef CONFIG_DYNAMIC_FTRACE #ifndef CONFIG_FTRACE_MCOUNT_RECORD @@ -2739,7 +2726,7 @@ static void ftrace_filter_reset(struct ftrace_hash *hash) * routine, you can use ftrace_filter_write() for the write * routine if @flag has FTRACE_ITER_FILTER set, or * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set. - * ftrace_filter_lseek() should be used as the lseek routine, and + * tracing_lseek() should be used as the lseek routine, and * release must call ftrace_regex_release(). */ int @@ -3767,7 +3754,7 @@ static const struct file_operations ftrace_filter_fops = { .open = ftrace_filter_open, .read = seq_read, .write = ftrace_filter_write, - .llseek = ftrace_filter_lseek, + .llseek = tracing_lseek, .release = ftrace_regex_release, }; @@ -3775,7 +3762,7 @@ static const struct file_operations ftrace_notrace_fops = { .open = ftrace_notrace_open, .read = seq_read, .write = ftrace_notrace_write, - .llseek = ftrace_filter_lseek, + .llseek = tracing_lseek, .release = ftrace_regex_release, }; @@ -4038,7 +4025,7 @@ static const struct file_operations ftrace_graph_fops = { .open = ftrace_graph_open, .read = seq_read, .write = ftrace_graph_write, - .llseek = ftrace_filter_lseek, + .llseek = tracing_lseek, .release = ftrace_graph_release, }; @@ -4046,7 +4033,7 @@ static const struct file_operations ftrace_graph_notrace_fops = { .open = ftrace_graph_notrace_open, .read = seq_read, .write = ftrace_graph_write, - .llseek = ftrace_filter_lseek, + .llseek = tracing_lseek, .release = ftrace_graph_release, }; #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ @@ -4719,7 +4706,7 @@ static const struct file_operations ftrace_pid_fops = { .open = ftrace_pid_open, .write = ftrace_pid_write, .read = seq_read, - .llseek = ftrace_filter_lseek, + .llseek = tracing_lseek, .release = ftrace_pid_release, }; diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 59bf5b56ccc0..e32a2f48dde1 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3183,19 +3183,23 @@ tracing_write_stub(struct file *filp, const char __user *ubuf, return count; } -static loff_t tracing_seek(struct file *file, loff_t offset, int origin) +loff_t tracing_lseek(struct file *file, loff_t offset, int whence) { + int ret; + if (file->f_mode & FMODE_READ) - return seq_lseek(file, offset, origin); + ret = seq_lseek(file, offset, whence); else - return 0; + file->f_pos = ret = 0; + + return ret; } static const struct file_operations tracing_fops = { .open = tracing_open, .read = seq_read, .write = tracing_write_stub, - .llseek = tracing_seek, + .llseek = tracing_lseek, .release = tracing_release, }; @@ -4940,7 +4944,7 @@ static const struct file_operations snapshot_fops = { .open = tracing_snapshot_open, .read = seq_read, .write = tracing_snapshot_write, - .llseek = tracing_seek, + .llseek = tracing_lseek, .release = tracing_snapshot_release, }; diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 433bfc5dd576..0380cab0af9b 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -588,6 +588,8 @@ void tracing_start_sched_switch_record(void); int register_tracer(struct tracer *type); int is_tracing_stopped(void); +loff_t tracing_lseek(struct file *file, loff_t offset, int whence); + extern cpumask_var_t __read_mostly tracing_buffer_mask; #define for_each_tracing_cpu(cpu) \ diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c index f5b3f780fda4..12ac8a5d4d95 100644 --- a/kernel/trace/trace_events_trigger.c +++ b/kernel/trace/trace_events_trigger.c @@ -281,7 +281,7 @@ const struct file_operations event_trigger_fops = { .open = event_trigger_open, .read = seq_read, .write = event_trigger_write, - .llseek = ftrace_filter_lseek, + .llseek = tracing_lseek, .release = event_trigger_release, }; diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c index b20428c5efe2..e6be585cf06a 100644 --- a/kernel/trace/trace_stack.c +++ b/kernel/trace/trace_stack.c @@ -382,7 +382,7 @@ static const struct file_operations stack_trace_filter_fops = { .open = stack_trace_filter_open, .read = seq_read, .write = ftrace_filter_write, - .llseek = ftrace_filter_lseek, + .llseek = tracing_lseek, .release = ftrace_regex_release, }; -- cgit v1.2.3-70-g09d2 From 13a1e4aef53b2a7684ddee374e749999ba103b4a Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Mon, 6 Jan 2014 21:32:10 -0500 Subject: tracing: Consolidate event trigger code The event trigger code that checks for callback triggers before and after recording of an event has lots of flags checks. This code is duplicated throughout the ftrace events, kprobes and system calls. They all do the exact same checks against the event flags. Added helper functions ftrace_trigger_soft_disabled(), event_trigger_unlock_commit() and event_trigger_unlock_commit_regs() that consolidated the code and these are used instead. Link: http://lkml.kernel.org/r/20140106222703.5e7dbba2@gandalf.local.home Acked-by: Tom Zanussi Tested-by: Tom Zanussi Signed-off-by: Steven Rostedt --- include/linux/ftrace_event.h | 117 ++++++++++++++++++++++++++++++++++++++++++ include/trace/ftrace.h | 23 ++------- kernel/trace/trace_kprobe.c | 48 +++-------------- kernel/trace/trace_syscalls.c | 48 +++-------------- 4 files changed, 137 insertions(+), 99 deletions(-) (limited to 'include') diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index 03d2db22ad0d..4e4cc28623ad 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -370,6 +370,123 @@ extern enum event_trigger_type event_triggers_call(struct ftrace_event_file *fil extern void event_triggers_post_call(struct ftrace_event_file *file, enum event_trigger_type tt); +/** + * ftrace_trigger_soft_disabled - do triggers and test if soft disabled + * @file: The file pointer of the event to test + * + * If any triggers without filters are attached to this event, they + * will be called here. If the event is soft disabled and has no + * triggers that require testing the fields, it will return true, + * otherwise false. + */ +static inline bool +ftrace_trigger_soft_disabled(struct ftrace_event_file *file) +{ + unsigned long eflags = file->flags; + + if (!(eflags & FTRACE_EVENT_FL_TRIGGER_COND)) { + if (eflags & FTRACE_EVENT_FL_TRIGGER_MODE) + event_triggers_call(file, NULL); + if (eflags & FTRACE_EVENT_FL_SOFT_DISABLED) + return true; + } + return false; +} + +/* + * Helper function for event_trigger_unlock_commit{_regs}(). + * If there are event triggers attached to this event that requires + * filtering against its fields, then they wil be called as the + * entry already holds the field information of the current event. + * + * It also checks if the event should be discarded or not. + * It is to be discarded if the event is soft disabled and the + * event was only recorded to process triggers, or if the event + * filter is active and this event did not match the filters. + * + * Returns true if the event is discarded, false otherwise. + */ +static inline bool +__event_trigger_test_discard(struct ftrace_event_file *file, + struct ring_buffer *buffer, + struct ring_buffer_event *event, + void *entry, + enum event_trigger_type *tt) +{ + unsigned long eflags = file->flags; + + if (eflags & FTRACE_EVENT_FL_TRIGGER_COND) + *tt = event_triggers_call(file, entry); + + if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &file->flags)) + ring_buffer_discard_commit(buffer, event); + else if (!filter_check_discard(file, entry, buffer, event)) + return false; + + return true; +} + +/** + * event_trigger_unlock_commit - handle triggers and finish event commit + * @file: The file pointer assoctiated to the event + * @buffer: The ring buffer that the event is being written to + * @event: The event meta data in the ring buffer + * @entry: The event itself + * @irq_flags: The state of the interrupts at the start of the event + * @pc: The state of the preempt count at the start of the event. + * + * This is a helper function to handle triggers that require data + * from the event itself. It also tests the event against filters and + * if the event is soft disabled and should be discarded. + */ +static inline void +event_trigger_unlock_commit(struct ftrace_event_file *file, + struct ring_buffer *buffer, + struct ring_buffer_event *event, + void *entry, unsigned long irq_flags, int pc) +{ + enum event_trigger_type tt = ETT_NONE; + + if (!__event_trigger_test_discard(file, buffer, event, entry, &tt)) + trace_buffer_unlock_commit(buffer, event, irq_flags, pc); + + if (tt) + event_triggers_post_call(file, tt); +} + +/** + * event_trigger_unlock_commit_regs - handle triggers and finish event commit + * @file: The file pointer assoctiated to the event + * @buffer: The ring buffer that the event is being written to + * @event: The event meta data in the ring buffer + * @entry: The event itself + * @irq_flags: The state of the interrupts at the start of the event + * @pc: The state of the preempt count at the start of the event. + * + * This is a helper function to handle triggers that require data + * from the event itself. It also tests the event against filters and + * if the event is soft disabled and should be discarded. + * + * Same as event_trigger_unlock_commit() but calls + * trace_buffer_unlock_commit_regs() instead of trace_buffer_unlock_commit(). + */ +static inline void +event_trigger_unlock_commit_regs(struct ftrace_event_file *file, + struct ring_buffer *buffer, + struct ring_buffer_event *event, + void *entry, unsigned long irq_flags, int pc, + struct pt_regs *regs) +{ + enum event_trigger_type tt = ETT_NONE; + + if (!__event_trigger_test_discard(file, buffer, event, entry, &tt)) + trace_buffer_unlock_commit_regs(buffer, event, + irq_flags, pc, regs); + + if (tt) + event_triggers_post_call(file, tt); +} + enum { FILTER_OTHER = 0, FILTER_STATIC_STRING, diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index 0962968b8b37..1a8b28db3775 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -546,8 +546,6 @@ ftrace_raw_event_##call(void *__data, proto) \ struct ftrace_event_file *ftrace_file = __data; \ struct ftrace_event_call *event_call = ftrace_file->event_call; \ struct ftrace_data_offsets_##call __maybe_unused __data_offsets;\ - unsigned long eflags = ftrace_file->flags; \ - enum event_trigger_type __tt = ETT_NONE; \ struct ring_buffer_event *event; \ struct ftrace_raw_##call *entry; \ struct ring_buffer *buffer; \ @@ -555,12 +553,8 @@ ftrace_raw_event_##call(void *__data, proto) \ int __data_size; \ int pc; \ \ - if (!(eflags & FTRACE_EVENT_FL_TRIGGER_COND)) { \ - if (eflags & FTRACE_EVENT_FL_TRIGGER_MODE) \ - event_triggers_call(ftrace_file, NULL); \ - if (eflags & FTRACE_EVENT_FL_SOFT_DISABLED) \ - return; \ - } \ + if (ftrace_trigger_soft_disabled(ftrace_file)) \ + return; \ \ local_save_flags(irq_flags); \ pc = preempt_count(); \ @@ -579,17 +573,8 @@ ftrace_raw_event_##call(void *__data, proto) \ \ { assign; } \ \ - if (eflags & FTRACE_EVENT_FL_TRIGGER_COND) \ - __tt = event_triggers_call(ftrace_file, entry); \ - \ - if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, \ - &ftrace_file->flags)) \ - ring_buffer_discard_commit(buffer, event); \ - else if (!filter_check_discard(ftrace_file, entry, buffer, event)) \ - trace_buffer_unlock_commit(buffer, event, irq_flags, pc); \ - \ - if (__tt) \ - event_triggers_post_call(ftrace_file, __tt); \ + event_trigger_unlock_commit(ftrace_file, buffer, event, entry, \ + irq_flags, pc); \ } /* * The ftrace_test_probe is compiled out, it is only here as a build time check diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 3afa716d6268..bdbae450c13e 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -929,20 +929,12 @@ __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs, struct ring_buffer *buffer; int size, dsize, pc; unsigned long irq_flags; - unsigned long eflags; - enum event_trigger_type tt = ETT_NONE; struct ftrace_event_call *call = &tk->tp.call; WARN_ON(call != ftrace_file->event_call); - eflags = ftrace_file->flags; - - if (!(eflags & FTRACE_EVENT_FL_TRIGGER_COND)) { - if (eflags & FTRACE_EVENT_FL_TRIGGER_MODE) - event_triggers_call(ftrace_file, NULL); - if (eflags & FTRACE_EVENT_FL_SOFT_DISABLED) - return; - } + if (ftrace_trigger_soft_disabled(ftrace_file)) + return; local_save_flags(irq_flags); pc = preempt_count(); @@ -960,16 +952,8 @@ __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs, entry->ip = (unsigned long)tk->rp.kp.addr; store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize); - if (eflags & FTRACE_EVENT_FL_TRIGGER_COND) - tt = event_triggers_call(ftrace_file, entry); - - if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags)) - ring_buffer_discard_commit(buffer, event); - else if (!filter_check_discard(ftrace_file, entry, buffer, event)) - trace_buffer_unlock_commit_regs(buffer, event, - irq_flags, pc, regs); - if (tt) - event_triggers_post_call(ftrace_file, tt); + event_trigger_unlock_commit_regs(ftrace_file, buffer, event, + entry, irq_flags, pc, regs); } static __kprobes void @@ -992,20 +976,12 @@ __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, struct ring_buffer *buffer; int size, pc, dsize; unsigned long irq_flags; - unsigned long eflags; - enum event_trigger_type tt = ETT_NONE; struct ftrace_event_call *call = &tk->tp.call; WARN_ON(call != ftrace_file->event_call); - eflags = ftrace_file->flags; - - if (!(eflags & FTRACE_EVENT_FL_TRIGGER_COND)) { - if (eflags & FTRACE_EVENT_FL_TRIGGER_MODE) - event_triggers_call(ftrace_file, NULL); - if (eflags & FTRACE_EVENT_FL_SOFT_DISABLED) - return; - } + if (ftrace_trigger_soft_disabled(ftrace_file)) + return; local_save_flags(irq_flags); pc = preempt_count(); @@ -1024,16 +1000,8 @@ __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, entry->ret_ip = (unsigned long)ri->ret_addr; store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize); - if (eflags & FTRACE_EVENT_FL_TRIGGER_COND) - tt = event_triggers_call(ftrace_file, entry); - - if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags)) - ring_buffer_discard_commit(buffer, event); - else if (!filter_check_discard(ftrace_file, entry, buffer, event)) - trace_buffer_unlock_commit_regs(buffer, event, - irq_flags, pc, regs); - if (tt) - event_triggers_post_call(ftrace_file, tt); + event_trigger_unlock_commit_regs(ftrace_file, buffer, event, + entry, irq_flags, pc, regs); } static __kprobes void diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index a4acf9bbffa7..759d5e004517 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -306,10 +306,8 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id) struct syscall_trace_enter *entry; struct syscall_metadata *sys_data; struct ring_buffer_event *event; - enum event_trigger_type tt = ETT_NONE; struct ring_buffer *buffer; unsigned long irq_flags; - unsigned long eflags; int pc; int syscall_nr; int size; @@ -323,14 +321,8 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id) if (!ftrace_file) return; - eflags = ftrace_file->flags; - - if (!(eflags & FTRACE_EVENT_FL_TRIGGER_COND)) { - if (eflags & FTRACE_EVENT_FL_TRIGGER_MODE) - event_triggers_call(ftrace_file, NULL); - if (eflags & FTRACE_EVENT_FL_SOFT_DISABLED) - return; - } + if (ftrace_trigger_soft_disabled(ftrace_file)) + return; sys_data = syscall_nr_to_meta(syscall_nr); if (!sys_data) @@ -351,16 +343,8 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id) entry->nr = syscall_nr; syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args); - if (eflags & FTRACE_EVENT_FL_TRIGGER_COND) - tt = event_triggers_call(ftrace_file, entry); - - if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags)) - ring_buffer_discard_commit(buffer, event); - else if (!filter_check_discard(ftrace_file, entry, buffer, event)) - trace_current_buffer_unlock_commit(buffer, event, - irq_flags, pc); - if (tt) - event_triggers_post_call(ftrace_file, tt); + event_trigger_unlock_commit(ftrace_file, buffer, event, entry, + irq_flags, pc); } static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret) @@ -370,10 +354,8 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret) struct syscall_trace_exit *entry; struct syscall_metadata *sys_data; struct ring_buffer_event *event; - enum event_trigger_type tt = ETT_NONE; struct ring_buffer *buffer; unsigned long irq_flags; - unsigned long eflags; int pc; int syscall_nr; @@ -386,14 +368,8 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret) if (!ftrace_file) return; - eflags = ftrace_file->flags; - - if (!(eflags & FTRACE_EVENT_FL_TRIGGER_COND)) { - if (eflags & FTRACE_EVENT_FL_TRIGGER_MODE) - event_triggers_call(ftrace_file, NULL); - if (eflags & FTRACE_EVENT_FL_SOFT_DISABLED) - return; - } + if (ftrace_trigger_soft_disabled(ftrace_file)) + return; sys_data = syscall_nr_to_meta(syscall_nr); if (!sys_data) @@ -413,16 +389,8 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret) entry->nr = syscall_nr; entry->ret = syscall_get_return_value(current, regs); - if (eflags & FTRACE_EVENT_FL_TRIGGER_COND) - tt = event_triggers_call(ftrace_file, entry); - - if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags)) - ring_buffer_discard_commit(buffer, event); - else if (!filter_check_discard(ftrace_file, entry, buffer, event)) - trace_current_buffer_unlock_commit(buffer, event, - irq_flags, pc); - if (tt) - event_triggers_post_call(ftrace_file, tt); + event_trigger_unlock_commit(ftrace_file, buffer, event, entry, + irq_flags, pc); } static int reg_event_syscall_enter(struct ftrace_event_file *file, -- cgit v1.2.3-70-g09d2