diff options
author | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-07-27 11:49:37 +0200 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-07-27 11:49:37 +0200 |
commit | 65a9bde6ed484880987a6d88de6e372eca52059f (patch) | |
tree | a192e1a8a54d334f457413f9c16041ffdf11533d /kernel/sched/core.c | |
parent | 860e73b49cd933c708e3e1e1e07cdea81b6acd1c (diff) | |
parent | 92ed301919932f777713b9172e525674157e983d (diff) | |
download | linux-65a9bde6ed484880987a6d88de6e372eca52059f.tar.bz2 |
Merge 5.8-rc7 into char-misc-next
This should resolve the merge/build issues reported when trying to
create linux-next.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel/sched/core.c')
-rw-r--r-- | kernel/sched/core.c | 25 |
1 files changed, 15 insertions, 10 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index e15543cb8481..2142c6767682 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -4119,9 +4119,6 @@ static void __sched notrace __schedule(bool preempt) local_irq_disable(); rcu_note_context_switch(preempt); - /* See deactivate_task() below. */ - prev_state = prev->state; - /* * Make sure that signal_pending_state()->signal_pending() below * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE) @@ -4145,11 +4142,16 @@ static void __sched notrace __schedule(bool preempt) update_rq_clock(rq); switch_count = &prev->nivcsw; + /* - * We must re-load prev->state in case ttwu_remote() changed it - * before we acquired rq->lock. + * We must load prev->state once (task_struct::state is volatile), such + * that: + * + * - we form a control dependency vs deactivate_task() below. + * - ptrace_{,un}freeze_traced() can change ->state underneath us. */ - if (!preempt && prev_state && prev_state == prev->state) { + prev_state = prev->state; + if (!preempt && prev_state) { if (signal_pending_state(prev_state, prev)) { prev->state = TASK_RUNNING; } else { @@ -4163,10 +4165,12 @@ static void __sched notrace __schedule(bool preempt) /* * __schedule() ttwu() - * prev_state = prev->state; if (READ_ONCE(p->on_rq) && ...) - * LOCK rq->lock goto out; - * smp_mb__after_spinlock(); smp_acquire__after_ctrl_dep(); - * p->on_rq = 0; p->state = TASK_WAKING; + * prev_state = prev->state; if (p->on_rq && ...) + * if (prev_state) goto out; + * p->on_rq = 0; smp_acquire__after_ctrl_dep(); + * p->state = TASK_WAKING + * + * Where __schedule() and ttwu() have matching control dependencies. * * After this, schedule() must not care about p->state any more. */ @@ -4481,6 +4485,7 @@ asmlinkage __visible void __sched preempt_schedule_irq(void) int default_wake_function(wait_queue_entry_t *curr, unsigned mode, int wake_flags, void *key) { + WARN_ON_ONCE(IS_ENABLED(CONFIG_SCHED_DEBUG) && wake_flags & ~WF_SYNC); return try_to_wake_up(curr->private, mode, wake_flags); } EXPORT_SYMBOL(default_wake_function); |