diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/hung_task.c | 2 | ||||
| -rw-r--r-- | kernel/kexec.c | 4 | ||||
| -rw-r--r-- | kernel/kexec_core.c | 94 | ||||
| -rw-r--r-- | kernel/kexec_file.c | 11 | ||||
| -rw-r--r-- | kernel/kthread.c | 5 | ||||
| -rw-r--r-- | kernel/user_namespace.c | 2 |
6 files changed, 111 insertions, 7 deletions
diff --git a/kernel/hung_task.c b/kernel/hung_task.c index c71889f3f3fc..322813366c6c 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -142,6 +142,8 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout) if (sysctl_hung_task_all_cpu_backtrace) hung_task_show_all_bt = true; + if (!sysctl_hung_task_warnings) + pr_info("Future hung task reports are suppressed, see sysctl kernel.hung_task_warnings\n"); } touch_nmi_watchdog(); diff --git a/kernel/kexec.c b/kernel/kexec.c index cb8e6e6f983c..92d301f98776 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -190,10 +190,12 @@ out_unlock: static inline int kexec_load_check(unsigned long nr_segments, unsigned long flags) { + int image_type = (flags & KEXEC_ON_CRASH) ? + KEXEC_TYPE_CRASH : KEXEC_TYPE_DEFAULT; int result; /* We only trust the superuser with rebooting the system. */ - if (!capable(CAP_SYS_BOOT) || kexec_load_disabled) + if (!kexec_load_permitted(image_type)) return -EPERM; /* Permit LSMs and IMA to fail the kexec */ diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index b1cf259854ca..3d578c6fefee 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -921,10 +921,64 @@ int kimage_load_segment(struct kimage *image, return result; } +struct kexec_load_limit { + /* Mutex protects the limit count. */ + struct mutex mutex; + int limit; +}; + +static struct kexec_load_limit load_limit_reboot = { + .mutex = __MUTEX_INITIALIZER(load_limit_reboot.mutex), + .limit = -1, +}; + +static struct kexec_load_limit load_limit_panic = { + .mutex = __MUTEX_INITIALIZER(load_limit_panic.mutex), + .limit = -1, +}; + struct kimage *kexec_image; struct kimage *kexec_crash_image; -int kexec_load_disabled; +static int kexec_load_disabled; + #ifdef CONFIG_SYSCTL +static int kexec_limit_handler(struct ctl_table *table, int write, + void *buffer, size_t *lenp, loff_t *ppos) +{ + struct kexec_load_limit *limit = table->data; + int val; + struct ctl_table tmp = { + .data = &val, + .maxlen = sizeof(val), + .mode = table->mode, + }; + int ret; + + if (write) { + ret = proc_dointvec(&tmp, write, buffer, lenp, ppos); + if (ret) + return ret; + + if (val < 0) + return -EINVAL; + + mutex_lock(&limit->mutex); + if (limit->limit != -1 && val >= limit->limit) + ret = -EINVAL; + else + limit->limit = val; + mutex_unlock(&limit->mutex); + + return ret; + } + + mutex_lock(&limit->mutex); + val = limit->limit; + mutex_unlock(&limit->mutex); + + return proc_dointvec(&tmp, write, buffer, lenp, ppos); +} + static struct ctl_table kexec_core_sysctls[] = { { .procname = "kexec_load_disabled", @@ -936,6 +990,18 @@ static struct ctl_table kexec_core_sysctls[] = { .extra1 = SYSCTL_ONE, .extra2 = SYSCTL_ONE, }, + { + .procname = "kexec_load_limit_panic", + .data = &load_limit_panic, + .mode = 0644, + .proc_handler = kexec_limit_handler, + }, + { + .procname = "kexec_load_limit_reboot", + .data = &load_limit_reboot, + .mode = 0644, + .proc_handler = kexec_limit_handler, + }, { } }; @@ -947,6 +1013,32 @@ static int __init kexec_core_sysctl_init(void) late_initcall(kexec_core_sysctl_init); #endif +bool kexec_load_permitted(int kexec_image_type) +{ + struct kexec_load_limit *limit; + + /* + * Only the superuser can use the kexec syscall and if it has not + * been disabled. + */ + if (!capable(CAP_SYS_BOOT) || kexec_load_disabled) + return false; + + /* Check limit counter and decrease it.*/ + limit = (kexec_image_type == KEXEC_TYPE_CRASH) ? + &load_limit_panic : &load_limit_reboot; + mutex_lock(&limit->mutex); + if (!limit->limit) { + mutex_unlock(&limit->mutex); + return false; + } + if (limit->limit != -1) + limit->limit--; + mutex_unlock(&limit->mutex); + + return true; +} + /* * No panic_cpu check version of crash_kexec(). This function is called * only when panic_cpu holds the current CPU number; this is the only CPU diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index dd5983010b7b..f1a0e4e3fb5c 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -326,11 +326,13 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, unsigned long, cmdline_len, const char __user *, cmdline_ptr, unsigned long, flags) { - int ret = 0, i; + int image_type = (flags & KEXEC_FILE_ON_CRASH) ? + KEXEC_TYPE_CRASH : KEXEC_TYPE_DEFAULT; struct kimage **dest_image, *image; + int ret = 0, i; /* We only trust the superuser with rebooting the system. */ - if (!capable(CAP_SYS_BOOT) || kexec_load_disabled) + if (!kexec_load_permitted(image_type)) return -EPERM; /* Make sure we have a legal set of flags */ @@ -342,11 +344,12 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, if (!kexec_trylock()) return -EBUSY; - dest_image = &kexec_image; - if (flags & KEXEC_FILE_ON_CRASH) { + if (image_type == KEXEC_TYPE_CRASH) { dest_image = &kexec_crash_image; if (kexec_crash_image) arch_kexec_unprotect_crashkres(); + } else { + dest_image = &kexec_image; } if (flags & KEXEC_FILE_UNLOAD) diff --git a/kernel/kthread.c b/kernel/kthread.c index f97fd01a2932..7e6751b29101 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -1382,6 +1382,10 @@ EXPORT_SYMBOL_GPL(kthread_flush_worker); * Flush and destroy @worker. The simple flush is enough because the kthread * worker API is used only in trivial scenarios. There are no multi-step state * machines needed. + * + * Note that this function is not responsible for handling delayed work, so + * caller should be responsible for queuing or canceling all delayed work items + * before invoke this function. */ void kthread_destroy_worker(struct kthread_worker *worker) { @@ -1393,6 +1397,7 @@ void kthread_destroy_worker(struct kthread_worker *worker) kthread_flush_worker(worker); kthread_stop(task); + WARN_ON(!list_empty(&worker->delayed_work_list)); WARN_ON(!list_empty(&worker->work_list)); kfree(worker); } diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index 54211dbd516c..1d8e47bed3f1 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -229,7 +229,7 @@ void __put_user_ns(struct user_namespace *ns) EXPORT_SYMBOL(__put_user_ns); /** - * idmap_key struct holds the information necessary to find an idmapping in a + * struct idmap_key - holds the information necessary to find an idmapping in a * sorted idmap array. It is passed to cmp_map_id() as first argument. */ struct idmap_key { |