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authorOleg Nesterov <oleg@redhat.com>2012-03-19 17:03:41 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2012-03-20 14:16:50 -0700
commitb6e238dceed36891cc633167afe7151f1f3d83c5 (patch)
treeeef4928c1a0cb1b56eb20f8d0ee592709d533f10 /kernel/signal.c
parente636825346b36a07ccfc8e30946d52855e21f681 (diff)
downloadlwn-b6e238dceed36891cc633167afe7151f1f3d83c5.tar.gz
lwn-b6e238dceed36891cc633167afe7151f1f3d83c5.zip
exit_signal: fix the "parent has changed security domain" logic
exit_notify() changes ->exit_signal if the parent already did exec. This doesn't really work, we are not going to send the signal now if there is another live thread or the exiting task is traced. The parent can exec before the last dies or the tracer detaches. Move this check into do_notify_parent() which actually sends the signal. The user-visible change is that we do not change ->exit_signal, and thus the exiting task is still "clone children" for do_wait()->eligible_child(__WCLONE). Hopefully this is fine, the current logic is racy anyway. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/signal.c')
-rw-r--r--kernel/signal.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/kernel/signal.c b/kernel/signal.c
index 8511e39813c7..e76001ccf5cd 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1652,6 +1652,15 @@ bool do_notify_parent(struct task_struct *tsk, int sig)
BUG_ON(!tsk->ptrace &&
(tsk->group_leader != tsk || !thread_group_empty(tsk)));
+ if (sig != SIGCHLD) {
+ /*
+ * This is only possible if parent == real_parent.
+ * Check if it has changed security domain.
+ */
+ if (tsk->parent_exec_id != tsk->parent->self_exec_id)
+ sig = SIGCHLD;
+ }
+
info.si_signo = sig;
info.si_errno = 0;
/*