diff options
| author | Oleg Nesterov <oleg@tv-sign.ru> | 2008-02-08 04:19:00 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2008-02-08 09:22:26 -0800 |
| commit | 6405f7f4675884b671bee66678e1c2859bdb0e56 (patch) | |
| tree | 31f0e42b011de36976f5a50b86aee7132f6b82b4 | |
| parent | c0c0b649d67aa775aa9851de61aade17504be70c (diff) | |
ptrace_stop: fix the race with ptrace detach+attach
If the tracer went away (may_ptrace_stop() failed), ptrace_stop() drops
tasklist and then changes the ->state from TASK_TRACED to TASK_RUNNING.
This can fool another tracer which attaches to us in between. Change the
->state under tasklist_lock to ensure that ptrace_check_attach() can't wrongly
succeed. Also, remove the unnecessary mb().
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | kernel/signal.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/kernel/signal.c b/kernel/signal.c index 6d6d1ab39e7..678bffa437c 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -1638,11 +1638,11 @@ static void ptrace_stop(int exit_code, int nostop_code, siginfo_t *info) } else { /* * By the time we got the lock, our tracer went away. - * Don't stop here. + * Don't drop the lock yet, another tracer may come. */ - read_unlock(&tasklist_lock); - set_current_state(TASK_RUNNING); + __set_current_state(TASK_RUNNING); current->exit_code = nostop_code; + read_unlock(&tasklist_lock); } /* |