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sched: Constrain locks in sched_submit_work() 

Even though sched_submit_work() is ran from preemptible context,
it is discouraged to have it use blocking locks due to the recursion
potential.

Enforce this.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20230908162254.999499-2-bigeasy@linutronix.de
This commit is contained in:
Peter Zijlstra 2023-09-08 18:22:48 +02:00
parent a432b7c0cf
commit 28bc55f654
1 changed files with 9 additions and 0 deletions
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9
kernel/sched/core.c
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@ -6720,11 +6720,18 @@ void __noreturn do_task_dead(void)
static inline void sched_submit_work(struct task_struct *tsk)
{
static DEFINE_WAIT_OVERRIDE_MAP(sched_map, LD_WAIT_CONFIG);
unsigned int task_flags;
if (task_is_running(tsk))
return;
/*
* Establish LD_WAIT_CONFIG context to ensure none of the code called
* will use a blocking primitive -- which would lead to recursion.
*/
lock_map_acquire_try(&sched_map);
task_flags = tsk->flags;
/*
* If a worker goes to sleep, notify and ask workqueue whether it
@ -6749,6 +6756,8 @@ static inline void sched_submit_work(struct task_struct *tsk)
* make sure to submit it to avoid deadlocks.
*/
blk_flush_plug(tsk->plug, true);
lock_map_release(&sched_map);
}
static void sched_update_worker(struct task_struct *tsk)