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authorOleg Nesterov <oleg@redhat.com>2012-03-14 19:55:38 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2012-03-20 14:16:50 -0700
commit5f8aadd8b9966d71a77bba52b9d499cc2f38269f (patch)
tree229735d79edf0c4cc82ac00ba1abaee63040ff6e
parented378a52dabf77b406b447fd3238f83ea24b71fa (diff)
downloadop-kernel-dev-5f8aadd8b9966d71a77bba52b9d499cc2f38269f.zip
op-kernel-dev-5f8aadd8b9966d71a77bba52b9d499cc2f38269f.tar.gz
CLONE_PARENT shouldn't allow to set ->exit_signal
The child must not control its ->exit_signal, it is the parent who decides which signal the child should use for notification. This means that CLONE_PARENT should not use "clone_flags & CSIGNAL", the forking task is the sibling of the new process and their parent doesn't control exit_signal in this case. This patch uses ->exit_signal of the forking process, but perhaps we should simply use SIGCHLD. We read group_leader->exit_signal lockless, this can race with the ORIGINAL_SIGNAL -> SIGCHLD transition, but this is fine. Potentially this change allows to kill self_exec_id/parent_exec_id. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--kernel/fork.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/kernel/fork.c b/kernel/fork.c
index 26a7a67..c4f38a8 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1340,7 +1340,13 @@ static struct task_struct *copy_process(unsigned long clone_flags,
clear_all_latency_tracing(p);
/* ok, now we should be set up.. */
- p->exit_signal = (clone_flags & CLONE_THREAD) ? -1 : (clone_flags & CSIGNAL);
+ if (clone_flags & CLONE_THREAD)
+ p->exit_signal = -1;
+ else if (clone_flags & CLONE_PARENT)
+ p->exit_signal = current->group_leader->exit_signal;
+ else
+ p->exit_signal = (clone_flags & CSIGNAL);
+
p->pdeath_signal = 0;
p->exit_state = 0;
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