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| author | Peter Zijlstra <peterz@infradead.org> | 2014-09-24 12:18:55 +0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-10-28 12:56:52 +0300 |
| commit | 8eb23b9f35aae413140d3fda766a98092c21e9b0 (patch) | |
| tree | 657a91ed72882475ada772da052a8a332d70a2dc /include/linux/sched.h | |
| parent | 26cabd31259ba43f68026ce3f62b78094124333f (diff) | |
| download | linux-8eb23b9f35aae413140d3fda766a98092c21e9b0.tar.xz | |
sched: Debug nested sleeps
Validate we call might_sleep() with TASK_RUNNING, which catches places
where we nest blocking primitives, eg. mutex usage in a wait loop.
Since all blocking is arranged through task_struct::state, nesting
this will cause the inner primitive to set TASK_RUNNING and the outer
will thus not block.
Another observed problem is calling a blocking function from
schedule()->sched_submit_work()->blk_schedule_flush_plug() which will
then destroy the task state for the actual __schedule() call that
comes after it.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: tglx@linutronix.de
Cc: ilya.dryomov@inktank.com
Cc: umgwanakikbuti@gmail.com
Cc: oleg@redhat.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140924082242.591637616@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/sched.h')
| -rw-r--r-- | include/linux/sched.h | 46 |
1 files changed, 44 insertions, 2 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index 320a9779f1b4..4648e07f7d6f 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -243,6 +243,43 @@ extern char ___assert_task_state[1 - 2*!!( ((task->state & TASK_UNINTERRUPTIBLE) != 0 && \ (task->flags & PF_FROZEN) == 0) +#ifdef CONFIG_DEBUG_ATOMIC_SLEEP + +#define __set_task_state(tsk, state_value) \ + do { \ + (tsk)->task_state_change = _THIS_IP_; \ + (tsk)->state = (state_value); \ + } while (0) +#define set_task_state(tsk, state_value) \ + do { \ + (tsk)->task_state_change = _THIS_IP_; \ + set_mb((tsk)->state, (state_value)); \ + } while (0) + +/* + * set_current_state() includes a barrier so that the write of current->state + * is correctly serialised wrt the caller's subsequent test of whether to + * actually sleep: + * + * set_current_state(TASK_UNINTERRUPTIBLE); + * if (do_i_need_to_sleep()) + * schedule(); + * + * If the caller does not need such serialisation then use __set_current_state() + */ +#define __set_current_state(state_value) \ + do { \ + current->task_state_change = _THIS_IP_; \ + current->state = (state_value); \ + } while (0) +#define set_current_state(state_value) \ + do { \ + current->task_state_change = _THIS_IP_; \ + set_mb(current->state, (state_value)); \ + } while (0) + +#else + #define __set_task_state(tsk, state_value) \ do { (tsk)->state = (state_value); } while (0) #define set_task_state(tsk, state_value) \ @@ -259,11 +296,13 @@ extern char ___assert_task_state[1 - 2*!!( * * If the caller does not need such serialisation then use __set_current_state() */ -#define __set_current_state(state_value) \ +#define __set_current_state(state_value) \ do { current->state = (state_value); } while (0) -#define set_current_state(state_value) \ +#define set_current_state(state_value) \ set_mb(current->state, (state_value)) +#endif + /* Task command name length */ #define TASK_COMM_LEN 16 @@ -1661,6 +1700,9 @@ struct task_struct { unsigned int sequential_io; unsigned int sequential_io_avg; #endif +#ifdef CONFIG_DEBUG_ATOMIC_SLEEP + unsigned long task_state_change; +#endif }; /* Future-safe accessor for struct task_struct's cpus_allowed. */ |