[PATCH] fix zap_thread's ptrace related problems
1. The tracee can go from ptrace_stop() to do_signal_stop()
after __ptrace_unlink(p).
2. It is unsafe to __ptrace_unlink(p) while p->parent may wait
for tasklist_lock in ptrace_detach().
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/fs/exec.c b/fs/exec.c
index 055378d..0e1c950 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1403,7 +1403,7 @@
do_each_thread(g,p) {
if (mm == p->mm && p != tsk &&
p->ptrace && p->parent->mm == mm) {
- __ptrace_unlink(p);
+ __ptrace_detach(p, 0);
}
} while_each_thread(g,p);
write_unlock_irq(&tasklist_lock);