4.4-stable review patch. If anyone has any objections, please let me know.
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From: Andy Lutomirski luto@kernel.org
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... Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- kernel/sched/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5206,7 +5206,7 @@ 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); finish_arch_post_lock_switch(); } mmdrop(mm);