Messages in this thread Patch in this message | | | Date | Wed, 16 Sep 2020 08:53:07 -0700 | From | "Paul E. McKenney" <> | Subject | sched/core: Allow try_invoke_on_locked_down_task() with irqs disabled |
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Hello, Peter!
Are you OK with your Signed-off-by on this patch?
Or is there some other approach you would prefer?
Thanx, Paul
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commit 903c5302fa2df20c4074ea1fef01b1be9b4065d7 Author: Peter Zijlstra <peterz@infradead.org> Date: Sat Aug 29 10:22:24 2020 -0700
sched/core: Allow try_invoke_on_locked_down_task() with irqs disabled 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/ Reported-by: syzbot+cb3b69ae80afd6535b0e@syzkaller.appspotmail.com Not-signed-off-by: Peter Zijlstra <peterz@infradead.org>
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 8471a0f..a814028 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2988,7 +2988,7 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) /** * 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. * @@ -3006,12 +3006,11 @@ try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) */ 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) @@ -3028,7 +3027,7 @@ 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; }
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