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sched/core: Allow try_invoke_on_locked_down_task() with irqs disabled

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The try_invoke_on_locked_down_task() function currently requires
that interrupts be enabled, but it is called with interrupts
disabled from rcu_print_task_stall(), resulting in an "IRQs not
enabled as expected" diagnostic.  This commit therefore updates
try_invoke_on_locked_down_task() to use raw_spin_lock_irqsave() instead
of raw_spin_lock_irq(), thus allowing use from either context.

Link: https://lore.kernel.org/lkml/000000000000903d5805ab908fc4@google.com/
Link: https://lore.kernel.org/lkml/20200928075729.GC2611@hirez.programming.kicks-ass.net/
Reported-by: syzbot+cb3b69ae80afd6535b0e@syzkaller.appspotmail.com
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Peter Zijlstra 2020-08-29 10:22:24 -07:00 committed by Paul E. McKenney
parent 1b04fa9900
commit 1b7af29554
1 changed files with 4 additions and 5 deletions
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9
kernel/sched/core.c
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@ -2989,7 +2989,7 @@ out:
/**
* try_invoke_on_locked_down_task - Invoke a function on task in fixed state
* @p: Process for which the function is to be invoked.
* @p: Process for which the function is to be invoked, can be @current.
* @func: Function to invoke.
* @arg: Argument to function.
*
@ -3007,12 +3007,11 @@ out:
*/
bool try_invoke_on_locked_down_task(struct task_struct *p, bool (*func)(struct task_struct *t, void *arg), void *arg)
{
bool ret = false;
struct rq_flags rf;
bool ret = false;
struct rq *rq;
lockdep_assert_irqs_enabled();
raw_spin_lock_irq(&p->pi_lock);
raw_spin_lock_irqsave(&p->pi_lock, rf.flags);
if (p->on_rq) {
rq = __task_rq_lock(p, &rf);
if (task_rq(p) == rq)
@ -3029,7 +3028,7 @@ bool try_invoke_on_locked_down_task(struct task_struct *p, bool (*func)(struct t
ret = func(p, arg);
}
}
raw_spin_unlock_irq(&p->pi_lock);
raw_spin_unlock_irqrestore(&p->pi_lock, rf.flags);
return ret;
}