diff options
| -rw-r--r-- | kernel/trace/Kconfig | 23 | ||||
| -rw-r--r-- | kernel/trace/trace.h | 1 | ||||
| -rw-r--r-- | kernel/trace/trace_events.c | 4 | ||||
| -rw-r--r-- | kernel/trace/trace_events_hist.c | 273 |
4 files changed, 301 insertions, 0 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 743647005f64..2aec9376825f 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -847,6 +847,29 @@ config KPROBE_EVENT_GEN_TEST If unsure, say N. +config HIST_TRIGGERS_DEBUG + bool "Hist trigger debug support" + depends on HIST_TRIGGERS + help + Add "hist_debug" file for each event, which when read will + dump out a bunch of internal details about the hist triggers + defined on that event. + + The hist_debug file serves a couple of purposes: + + - Helps developers verify that nothing is broken. + + - Provides educational information to support the details + of the hist trigger internals as described by + Documentation/trace/histogram-design.rst. + + The hist_debug output only covers the data structures + related to the histogram definitions themselves and doesn't + display the internals of map buckets or variable values of + running histograms. + + If unsure, say N. + endif # FTRACE endif # TRACING_SUPPORT diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 4eb1d004d5f2..def769df5bf1 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -1661,6 +1661,7 @@ extern struct list_head ftrace_events; extern const struct file_operations event_trigger_fops; extern const struct file_operations event_hist_fops; +extern const struct file_operations event_hist_debug_fops; extern const struct file_operations event_inject_fops; #ifdef CONFIG_HIST_TRIGGERS diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 242f59e7f17d..f6f55682d3e2 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -2209,6 +2209,10 @@ event_create_dir(struct dentry *parent, struct trace_event_file *file) trace_create_file("hist", 0444, file->dir, file, &event_hist_fops); #endif +#ifdef CONFIG_HIST_TRIGGERS_DEBUG + trace_create_file("hist_debug", 0444, file->dir, file, + &event_hist_debug_fops); +#endif trace_create_file("format", 0444, file->dir, call, &ftrace_event_format_fops); diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 5cfe8f998b3e..313227da4925 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -6478,6 +6478,279 @@ const struct file_operations event_hist_fops = { .release = single_release, }; +#ifdef CONFIG_HIST_TRIGGERS_DEBUG +static void hist_field_debug_show_flags(struct seq_file *m, + unsigned long flags) +{ + seq_puts(m, " flags:\n"); + + if (flags & HIST_FIELD_FL_KEY) + seq_puts(m, " HIST_FIELD_FL_KEY\n"); + else if (flags & HIST_FIELD_FL_HITCOUNT) + seq_puts(m, " VAL: HIST_FIELD_FL_HITCOUNT\n"); + else if (flags & HIST_FIELD_FL_VAR) + seq_puts(m, " HIST_FIELD_FL_VAR\n"); + else if (flags & HIST_FIELD_FL_VAR_REF) + seq_puts(m, " HIST_FIELD_FL_VAR_REF\n"); + else + seq_puts(m, " VAL: normal u64 value\n"); + + if (flags & HIST_FIELD_FL_ALIAS) + seq_puts(m, " HIST_FIELD_FL_ALIAS\n"); +} + +static int hist_field_debug_show(struct seq_file *m, + struct hist_field *field, unsigned long flags) +{ + if ((field->flags & flags) != flags) { + seq_printf(m, "ERROR: bad flags - %lx\n", flags); + return -EINVAL; + } + + hist_field_debug_show_flags(m, field->flags); + if (field->field) + seq_printf(m, " ftrace_event_field name: %s\n", + field->field->name); + + if (field->flags & HIST_FIELD_FL_VAR) { + seq_printf(m, " var.name: %s\n", field->var.name); + seq_printf(m, " var.idx (into tracing_map_elt.vars[]): %u\n", + field->var.idx); + } + + if (field->flags & HIST_FIELD_FL_ALIAS) + seq_printf(m, " var_ref_idx (into hist_data->var_refs[]): %u\n", + field->var_ref_idx); + + if (field->flags & HIST_FIELD_FL_VAR_REF) { + seq_printf(m, " name: %s\n", field->name); + seq_printf(m, " var.idx (into tracing_map_elt.vars[]): %u\n", + field->var.idx); + seq_printf(m, " var.hist_data: %p\n", field->var.hist_data); + seq_printf(m, " var_ref_idx (into hist_data->var_refs[]): %u\n", + field->var_ref_idx); + if (field->system) + seq_printf(m, " system: %s\n", field->system); + if (field->event_name) + seq_printf(m, " event_name: %s\n", field->event_name); + } + + seq_printf(m, " type: %s\n", field->type); + seq_printf(m, " size: %u\n", field->size); + seq_printf(m, " is_signed: %u\n", field->is_signed); + + return 0; +} + +static int field_var_debug_show(struct seq_file *m, + struct field_var *field_var, unsigned int i, + bool save_vars) +{ + const char *vars_name = save_vars ? "save_vars" : "field_vars"; + struct hist_field *field; + int ret = 0; + + seq_printf(m, "\n hist_data->%s[%d]:\n", vars_name, i); + + field = field_var->var; + + seq_printf(m, "\n %s[%d].var:\n", vars_name, i); + + hist_field_debug_show_flags(m, field->flags); + seq_printf(m, " var.name: %s\n", field->var.name); + seq_printf(m, " var.idx (into tracing_map_elt.vars[]): %u\n", + field->var.idx); + + field = field_var->val; + + seq_printf(m, "\n %s[%d].val:\n", vars_name, i); + if (field->field) + seq_printf(m, " ftrace_event_field name: %s\n", + field->field->name); + else { + ret = -EINVAL; + goto out; + } + + seq_printf(m, " type: %s\n", field->type); + seq_printf(m, " size: %u\n", field->size); + seq_printf(m, " is_signed: %u\n", field->is_signed); +out: + return ret; +} + +static int hist_action_debug_show(struct seq_file *m, + struct action_data *data, int i) +{ + int ret = 0; + + if (data->handler == HANDLER_ONMAX || + data->handler == HANDLER_ONCHANGE) { + seq_printf(m, "\n hist_data->actions[%d].track_data.var_ref:\n", i); + ret = hist_field_debug_show(m, data->track_data.var_ref, + HIST_FIELD_FL_VAR_REF); + if (ret) + goto out; + + seq_printf(m, "\n hist_data->actions[%d].track_data.track_var:\n", i); + ret = hist_field_debug_show(m, data->track_data.track_var, + HIST_FIELD_FL_VAR); + if (ret) + goto out; + } + + if (data->handler == HANDLER_ONMATCH) { + seq_printf(m, "\n hist_data->actions[%d].match_data.event_system: %s\n", + i, data->match_data.event_system); + seq_printf(m, " hist_data->actions[%d].match_data.event: %s\n", + i, data->match_data.event); + } +out: + return ret; +} + +static int hist_actions_debug_show(struct seq_file *m, + struct hist_trigger_data *hist_data) +{ + int i, ret = 0; + + if (hist_data->n_actions) + seq_puts(m, "\n action tracking variables (for onmax()/onchange()/onmatch()):\n"); + + for (i = 0; i < hist_data->n_actions; i++) { + struct action_data *action = hist_data->actions[i]; + + ret = hist_action_debug_show(m, action, i); + if (ret) + goto out; + } + + if (hist_data->n_save_vars) + seq_puts(m, "\n save action variables (save() params):\n"); + + for (i = 0; i < hist_data->n_save_vars; i++) { + ret = field_var_debug_show(m, hist_data->save_vars[i], i, true); + if (ret) + goto out; + } +out: + return ret; +} + +static void hist_trigger_debug_show(struct seq_file *m, + struct event_trigger_data *data, int n) +{ + struct hist_trigger_data *hist_data; + int i, ret; + + if (n > 0) + seq_puts(m, "\n\n"); + + seq_puts(m, "# event histogram\n#\n# trigger info: "); + data->ops->print(m, data->ops, data); + seq_puts(m, "#\n\n"); + + hist_data = data->private_data; + + seq_printf(m, "hist_data: %p\n\n", hist_data); + seq_printf(m, " n_vals: %u\n", hist_data->n_vals); + seq_printf(m, " n_keys: %u\n", hist_data->n_keys); + seq_printf(m, " n_fields: %u\n", hist_data->n_fields); + + seq_puts(m, "\n val fields:\n\n"); + + seq_puts(m, " hist_data->fields[0]:\n"); + ret = hist_field_debug_show(m, hist_data->fields[0], + HIST_FIELD_FL_HITCOUNT); + if (ret) + return; + + for (i = 1; i < hist_data->n_vals; i++) { + seq_printf(m, "\n hist_data->fields[%d]:\n", i); + ret = hist_field_debug_show(m, hist_data->fields[i], 0); + if (ret) + return; + } + + seq_puts(m, "\n key fields:\n"); + + for (i = hist_data->n_vals; i < hist_data->n_fields; i++) { + seq_printf(m, "\n hist_data->fields[%d]:\n", i); + ret = hist_field_debug_show(m, hist_data->fields[i], + HIST_FIELD_FL_KEY); + if (ret) + return; + } + + if (hist_data->n_var_refs) + seq_puts(m, "\n variable reference fields:\n"); + + for (i = 0; i < hist_data->n_var_refs; i++) { + seq_printf(m, "\n hist_data->var_refs[%d]:\n", i); + ret = hist_field_debug_show(m, hist_data->var_refs[i], + HIST_FIELD_FL_VAR_REF); + if (ret) + return; + } + + if (hist_data->n_field_vars) + seq_puts(m, "\n field variables:\n"); + + for (i = 0; i < hist_data->n_field_vars; i++) { + ret = field_var_debug_show(m, hist_data->field_vars[i], i, false); + if (ret) + return; + } + + ret = hist_actions_debug_show(m, hist_data); + if (ret) + return; +} + +static int hist_debug_show(struct seq_file *m, void *v) +{ + struct event_trigger_data *data; + struct trace_event_file *event_file; + int n = 0, ret = 0; + + mutex_lock(&event_mutex); + + event_file = event_file_data(m->private); + if (unlikely(!event_file)) { + ret = -ENODEV; + goto out_unlock; + } + + list_for_each_entry(data, &event_file->triggers, list) { + if (data->cmd_ops->trigger_type == ETT_EVENT_HIST) + hist_trigger_debug_show(m, data, n++); + } + + out_unlock: + mutex_unlock(&event_mutex); + + return ret; +} + +static int event_hist_debug_open(struct inode *inode, struct file *file) +{ + int ret; + + ret = security_locked_down(LOCKDOWN_TRACEFS); + if (ret) + return ret; + + return single_open(file, hist_debug_show, file); +} + +const struct file_operations event_hist_debug_fops = { + .open = event_hist_debug_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; +#endif + static void hist_field_print(struct seq_file *m, struct hist_field *hist_field) { const char *field_name = hist_field_name(hist_field, 0); |