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authorPeter Zijlstra <peterz@infradead.org>2015-09-28 17:57:39 +0200
committerIngo Molnar <mingo@kernel.org>2015-10-06 17:08:17 +0200
commit1dc0fffc48af94513e621f95dff730ed4f7317ec (patch)
tree602dbd67f0565830ea99196d71e7f47b17d849e3 /kernel/exit.c
parent3d8f74dd4ca1da8a1a464bbafcf679e40c2fc10f (diff)
downloadlinux-sh-1dc0fffc48af94513e621f95dff730ed4f7317ec.tar.gz
sched/core: Robustify preemption leak checks
When we warn about a preempt_count leak; reset the preempt_count to the known good value such that the problem does not ripple forward. This is most important on x86 which has a per cpu preempt_count that is not saved/restored (after this series). So if you schedule with an invalid (!2*PREEMPT_DISABLE_OFFSET) preempt_count the next task is messed up too. Enforcing this invariant limits the borkage to just the one task. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/exit.c')
-rw-r--r--kernel/exit.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index ea95ee1b5ef7..443677c8efe6 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -706,10 +706,12 @@ void do_exit(long code)
smp_mb();
raw_spin_unlock_wait(&tsk->pi_lock);
- if (unlikely(in_atomic()))
+ if (unlikely(in_atomic())) {
pr_info("note: %s[%d] exited with preempt_count %d\n",
current->comm, task_pid_nr(current),
preempt_count());
+ preempt_count_set(PREEMPT_ENABLED);
+ }
/* sync mm's RSS info before statistics gathering */
if (tsk->mm)