From 7b637745642aa7af60409f03c876f8a44cd7a360 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Wed, 9 Mar 2016 14:08:18 -0800 Subject: [PATCH] UPSTREAM: sched/kasan: remove stale KASAN poison after hotplug Functions which the compiler has instrumented for KASAN place poison on the stack shadow upon entry and remove this poision prior to returning. In the case of CPU hotplug, CPUs exit the kernel a number of levels deep in C code. Any instrumented functions on this critical path will leave portions of the stack shadow poisoned. When a CPU is subsequently brought back into the kernel via a different path, depending on stackframe, layout calls to instrumented functions may hit this stale poison, resulting in (spurious) KASAN splats to the console. To avoid this, clear any stale poison from the idle thread for a CPU prior to bringing a CPU online. Change-Id: Idd24e933ce0a93b500d17de8262afe6e43d565c8 Signed-off-by: Mark Rutland Acked-by: Catalin Marinas Reviewed-by: Andrey Ryabinin Reviewed-by: Ingo Molnar Cc: Alexander Potapenko Cc: Lorenzo Pieralisi Cc: Peter Zijlstra Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Tao Huang (cherry picked from commit e1b77c92981a522223bd1ac118fdcade6b7ad086) --- kernel/sched/core.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index fb6076ca98d2..31a636085ac8 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -26,6 +26,7 @@ * Thomas Gleixner, Mike Kravetz */ +#include #include #include #include @@ -5191,6 +5192,8 @@ void init_idle(struct task_struct *idle, int cpu) idle->state = TASK_RUNNING; idle->se.exec_start = sched_clock(); + kasan_unpoison_task_stack(idle); + #ifdef CONFIG_SMP /* * Its possible that init_idle() gets called multiple times on a task,