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| author | Catalin Marinas <catalin.marinas@arm.com> | 2016-10-27 17:46:47 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-10-27 18:43:43 -0700 |
| commit | 37df49f433bc3a11f5716fe65aaec5189c6402cb (patch) | |
| tree | 60265296d843c73e11f962bdf7560f0bb2bad43c /mm/kmemleak.c | |
| parent | 02754e0a484a50a92d44c38879f2cb2792ebc572 (diff) | |
| download | lwn-37df49f433bc3a11f5716fe65aaec5189c6402cb.tar.gz lwn-37df49f433bc3a11f5716fe65aaec5189c6402cb.zip | |
mm: kmemleak: ensure that the task stack is not freed during scanning
Commit 68f24b08ee89 ("sched/core: Free the stack early if
CONFIG_THREAD_INFO_IN_TASK") may cause the task->stack to be freed
during kmemleak_scan() execution, leading to either a NULL pointer fault
(if task->stack is NULL) or kmemleak accessing already freed memory.
This patch uses the new try_get_task_stack() API to ensure that the task
stack is not freed during kmemleak stack scanning.
Addresses https://bugzilla.kernel.org/show_bug.cgi?id=173901.
Fixes: 68f24b08ee89 ("sched/core: Free the stack early if CONFIG_THREAD_INFO_IN_TASK")
Link: http://lkml.kernel.org/r/1476266223-14325-1-git-send-email-catalin.marinas@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: CAI Qian <caiqian@redhat.com>
Tested-by: CAI Qian <caiqian@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: CAI Qian <caiqian@redhat.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/kmemleak.c')
| -rw-r--r-- | mm/kmemleak.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/mm/kmemleak.c b/mm/kmemleak.c index a5e453cf05c4..e5355a5b423f 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -1453,8 +1453,11 @@ static void kmemleak_scan(void) read_lock(&tasklist_lock); do_each_thread(g, p) { - scan_block(task_stack_page(p), task_stack_page(p) + - THREAD_SIZE, NULL); + void *stack = try_get_task_stack(p); + if (stack) { + scan_block(stack, stack + THREAD_SIZE, NULL); + put_task_stack(p); + } } while_each_thread(g, p); read_unlock(&tasklist_lock); } |