diff options
Diffstat (limited to 'kernel/hung_task.c')
-rw-r--r-- | kernel/hung_task.c | 78 |
1 files changed, 41 insertions, 37 deletions
diff --git a/kernel/hung_task.c b/kernel/hung_task.c index 8708a1205f82..b2c1f14b8129 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -95,9 +95,41 @@ static struct notifier_block panic_block = { .notifier_call = hung_task_panic, }; +static bool task_is_hung(struct task_struct *t, unsigned long timeout) +{ + unsigned long switch_count = t->nvcsw + t->nivcsw; + unsigned int state = READ_ONCE(t->__state); + + /* + * skip the TASK_KILLABLE tasks -- these can be killed + * skip the TASK_IDLE tasks -- those are genuinely idle + * skip the TASK_FROZEN task -- it reasonably stops scheduling by freezer + */ + if (!(state & TASK_UNINTERRUPTIBLE) || + (state & (TASK_WAKEKILL | TASK_NOLOAD | TASK_FROZEN))) + return false; + + /* + * When a freshly created task is scheduled once, changes its state to + * TASK_UNINTERRUPTIBLE without having ever been switched out once, it + * musn't be checked. + */ + if (unlikely(!switch_count)) + return false; + + if (switch_count != t->last_switch_count) { + t->last_switch_count = switch_count; + t->last_switch_time = jiffies; + return false; + } + if (time_is_after_jiffies(t->last_switch_time + timeout * HZ)) + return false; + + return true; +} #ifdef CONFIG_DETECT_HUNG_TASK_BLOCKER -static void debug_show_blocker(struct task_struct *task) +static void debug_show_blocker(struct task_struct *task, unsigned long timeout) { struct task_struct *g, *t; unsigned long owner, blocker, blocker_type; @@ -174,41 +206,21 @@ static void debug_show_blocker(struct task_struct *task) t->pid, rwsem_blocked_by); break; } - sched_show_task(t); + /* Avoid duplicated task dump, skip if the task is also hung. */ + if (!task_is_hung(t, timeout)) + sched_show_task(t); return; } } #else -static inline void debug_show_blocker(struct task_struct *task) +static inline void debug_show_blocker(struct task_struct *task, unsigned long timeout) { } #endif static void check_hung_task(struct task_struct *t, unsigned long timeout) { - unsigned long switch_count = t->nvcsw + t->nivcsw; - - /* - * Ensure the task is not frozen. - * Also, skip vfork and any other user process that freezer should skip. - */ - if (unlikely(READ_ONCE(t->__state) & TASK_FROZEN)) - return; - - /* - * When a freshly created task is scheduled once, changes its state to - * TASK_UNINTERRUPTIBLE without having ever been switched out once, it - * musn't be checked. - */ - if (unlikely(!switch_count)) - return; - - if (switch_count != t->last_switch_count) { - t->last_switch_count = switch_count; - t->last_switch_time = jiffies; - return; - } - if (time_is_after_jiffies(t->last_switch_time + timeout * HZ)) + if (!task_is_hung(t, timeout)) return; /* @@ -243,7 +255,7 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout) pr_err("\"echo 0 > /proc/sys/kernel/hung_task_timeout_secs\"" " disables this message.\n"); sched_show_task(t); - debug_show_blocker(t); + debug_show_blocker(t, timeout); hung_task_show_lock = true; if (sysctl_hung_task_all_cpu_backtrace) @@ -299,7 +311,6 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout) hung_task_show_lock = false; rcu_read_lock(); for_each_process_thread(g, t) { - unsigned int state; if (!max_count--) goto unlock; @@ -308,15 +319,8 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout) goto unlock; last_break = jiffies; } - /* - * skip the TASK_KILLABLE tasks -- these can be killed - * skip the TASK_IDLE tasks -- those are genuinely idle - */ - state = READ_ONCE(t->__state); - if ((state & TASK_UNINTERRUPTIBLE) && - !(state & TASK_WAKEKILL) && - !(state & TASK_NOLOAD)) - check_hung_task(t, timeout); + + check_hung_task(t, timeout); } unlock: rcu_read_unlock(); |