Messages in this thread Patch in this message | | | Date | Wed, 27 Nov 2013 06:10:30 -0800 | From | tip-bot for Oleg Nesterov <> | Subject | [tip:sched/core] sched: Check TASK_DEAD rather than EXIT_DEAD in schedule_debug() |
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Commit-ID: 192301e70af3f6803c6354a464ebfa742da738ae Gitweb: http://git.kernel.org/tip/192301e70af3f6803c6354a464ebfa742da738ae Author: Oleg Nesterov <oleg@redhat.com> AuthorDate: Wed, 13 Nov 2013 16:45:38 +0100 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Wed, 27 Nov 2013 13:50:53 +0100
sched: Check TASK_DEAD rather than EXIT_DEAD in schedule_debug()
schedule_debug() ignores in_atomic() if prev->exit_state != 0. This is not what we want, ->exit_state is set by exit_notify() but we should complain until the task does the last schedule() in TASK_DEAD.
See also 7407251a0e2e "PF_DEAD cleanup", I think this ancient commit explains why schedule() had to rely on ->exit_state, until that commit exit_notify() disabled preemption and set PF_DEAD which was used to detect the exiting task.
Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: David Laight <David.Laight@ACULAB.COM> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Tejun Heo <tj@kernel.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20131113154538.GB15810@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> --- kernel/sched/core.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 687985b..19db8f3 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2414,10 +2414,10 @@ static inline void schedule_debug(struct task_struct *prev) { /* * Test if we are atomic. Since do_exit() needs to call into - * schedule() atomically, we ignore that path for now. - * Otherwise, whine if we are scheduling when we should not be. + * schedule() atomically, we ignore that path. Otherwise whine + * if we are scheduling when we should not. */ - if (unlikely(in_atomic_preempt_off() && !prev->exit_state)) + if (unlikely(in_atomic_preempt_off() && prev->state != TASK_DEAD)) __schedule_bug(prev); rcu_sleep_check();
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