This is a note to let you know that I've just added the patch titled

sched/core: Add switch_mm_irqs_off() and use it in the scheduler

to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: sched-core-add-switch_mm_irqs_off-and-use-it-in-the-scheduler.patch and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From f98db6013c557c216da5038d9c52045be55cd039 Mon Sep 17 00:00:00 2001

From: Andy Lutomirski luto@kernel.org Date: Tue, 26 Apr 2016 09:39:06 -0700 Subject: sched/core: Add switch_mm_irqs_off() and use it in the scheduler

From: Andy Lutomirski luto@kernel.org

commit f98db6013c557c216da5038d9c52045be55cd039 upstream.

By default, this is the same thing as switch_mm().

x86 will override it as an optimization.

Signed-off-by: Andy Lutomirski luto@kernel.org Reviewed-by: Borislav Petkov bp@suse.de Cc: Borislav Petkov bp@alien8.de Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Link: http://lkml.kernel.org/r/df401df47bdd6be3e389c6f1e3f5310d70e81b2c.1461688545... Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- include/linux/mmu_context.h | 7 +++++++ kernel/sched/core.c | 6 +++--- 2 files changed, 10 insertions(+), 3 deletions(-)

--- a/include/linux/mmu_context.h +++ b/include/linux/mmu_context.h @@ -1,9 +1,16 @@ #ifndef _LINUX_MMU_CONTEXT_H #define _LINUX_MMU_CONTEXT_H

+#include <asm/mmu_context.h> + struct mm_struct;

void use_mm(struct mm_struct *mm); void unuse_mm(struct mm_struct *mm);

+/* Architectures that care about IRQ state in switch_mm can override this. */ +#ifndef switch_mm_irqs_off +# define switch_mm_irqs_off switch_mm +#endif + #endif --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -32,7 +32,7 @@ #include <linux/init.h> #include <linux/uaccess.h> #include <linux/highmem.h> -#include <asm/mmu_context.h> +#include <linux/mmu_context.h> #include <linux/interrupt.h> #include <linux/capability.h> #include <linux/completion.h> @@ -2708,7 +2708,7 @@ context_switch(struct rq *rq, struct tas atomic_inc(&oldmm->mm_count); enter_lazy_tlb(oldmm, next); } else - switch_mm(oldmm, mm, next); + switch_mm_irqs_off(oldmm, mm, next);

if (!prev->mm) { prev->active_mm = NULL; @@ -5206,7 +5206,7 @@ void idle_task_exit(void) BUG_ON(cpu_online(smp_processor_id()));

if (mm != &init_mm) { - switch_mm(mm, &init_mm, current); + switch_mm_irqs_off(mm, &init_mm, current); finish_arch_post_lock_switch(); } mmdrop(mm);

Patches currently in stable-queue which might be from luto@kernel.org are

queue-4.4/x86-mm-sched-core-uninline-switch_mm.patch queue-4.4/x86-mm-add-a-noinvpcid-boot-option-to-turn-off-invpcid.patch queue-4.4/x86-irq-do-not-substract-irq_tlb_count-from-irq_call_count.patch queue-4.4/x86-mm-if-invpcid-is-available-use-it-to-flush-global-mappings.patch queue-4.4/x86-mm-add-invpcid-helpers.patch queue-4.4/sched-core-add-switch_mm_irqs_off-and-use-it-in-the-scheduler.patch queue-4.4/arm-hide-finish_arch_post_lock_switch-from-modules.patch queue-4.4/x86-mm-sched-core-turn-off-irqs-in-switch_mm.patch queue-4.4/mm-mmu_context-sched-core-fix-mmu_context.h-assumption.patch queue-4.4/x86-mm-build-arch-x86-mm-tlb.c-even-on-smp.patch queue-4.4/sched-core-idle_task_exit-shouldn-t-use-switch_mm_irqs_off.patch