| From: Andy Lutomirski <luto@kernel.org> |
| Date: Fri, 9 Jun 2017 11:49:15 -0700 |
| Subject: sched/core: Idle_task_exit() shouldn't use switch_mm_irqs_off() |
| |
| commit 252d2a4117bc181b287eeddf848863788da733ae upstream. |
| |
| idle_task_exit() can be called with IRQs on x86 on and therefore |
| should use switch_mm(), not switch_mm_irqs_off(). |
| |
| This doesn't seem to cause any problems right now, but it will |
| confuse my upcoming TLB flush changes. Nonetheless, I think it |
| should be backported because it's trivial. There won't be any |
| meaningful performance impact because idle_task_exit() is only |
| used when offlining a CPU. |
| |
| Signed-off-by: Andy Lutomirski <luto@kernel.org> |
| Cc: Borislav Petkov <bp@suse.de> |
| Cc: Linus Torvalds <torvalds@linux-foundation.org> |
| Cc: Peter Zijlstra <peterz@infradead.org> |
| Cc: Thomas Gleixner <tglx@linutronix.de> |
| Cc: stable@vger.kernel.org |
| Fixes: f98db6013c55 ("sched/core: Add switch_mm_irqs_off() and use it in the scheduler") |
| Link: http://lkml.kernel.org/r/ca3d1a9fa93a0b49f5a8ff729eda3640fb6abdf9.1497034141.git.luto@kernel.org |
| Signed-off-by: Ingo Molnar <mingo@kernel.org> |
| Signed-off-by: Hugh Dickins <hughd@google.com> |
| Signed-off-by: Ben Hutchings <ben@decadent.org.uk> |
| --- |
| kernel/sched.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| diff --git a/kernel/sched.c b/kernel/sched.c |
| index 2d7b0f92b2ac..f0f941f3634a 100644 |
| --- a/kernel/sched.c |
| +++ b/kernel/sched.c |
| @@ -6553,7 +6553,7 @@ void idle_task_exit(void) |
| BUG_ON(cpu_online(smp_processor_id())); |
| |
| if (mm != &init_mm) |
| - switch_mm_irqs_off(mm, &init_mm, current); |
| + switch_mm(mm, &init_mm, current); |
| mmdrop(mm); |
| } |
| |
| |
