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authorMark Rutland <mark.rutland@arm.com>2016-03-09 23:08:18 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2016-03-10 00:43:42 +0100
commite1b77c92981a522223bd1ac118fdcade6b7ad086 (patch)
tree7f726e17665a8dcb0b4c24a6d73a559a37db2148 /kernel
parentkasan: add functions to clear stack poison (diff)
downloadlinux-e1b77c92981a522223bd1ac118fdcade6b7ad086.tar.xz
linux-e1b77c92981a522223bd1ac118fdcade6b7ad086.zip
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. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Alexander Potapenko <glider@google.com> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched/core.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 9503d590e5ef..41f6b2215aa8 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -26,6 +26,7 @@
* Thomas Gleixner, Mike Kravetz
*/
+#include <linux/kasan.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/nmi.h>
@@ -5096,6 +5097,8 @@ 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,