diff options
| author | Mark Rutland <mark.rutland@arm.com> | 2016-03-09 14:08:18 -0800 |
|---|---|---|
| committer | Alex Shi <alex.shi@linaro.org> | 2016-05-25 22:16:08 +0800 |
| commit | e31e93969c75a4ffc43f88e60b42ae519e115791 (patch) | |
| tree | b26414caa89fbafc2ec267977844355615696879 | |
| parent | 207348ba0e969f552d097fe536ea078d82d32559 (diff) | |
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>
(cherry picked from commit e1b77c92981a522223bd1ac118fdcade6b7ad086)
Signed-off-by: Alex Shi <alex.shi@linaro.org>
Conflicts:
kernel/sched/core.c
| -rw-r--r-- | kernel/sched/core.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 4d870eb6086b..b6d58ab44c9d 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> @@ -4611,7 +4612,9 @@ void init_idle(struct task_struct *idle, int cpu) idle->state = TASK_RUNNING; idle->se.exec_start = sched_clock(); + kasan_unpoison_task_stack(idle); do_set_cpus_allowed(idle, cpumask_of(cpu)); + /* * We're having a chicken and egg problem, even though we are * holding rq->lock, the cpu isn't yet set to this cpu so the |