tree 590f845665e166694ba0f9ba0e6d2267e15d8aae
parent b1442b055c154699a6a2c436f3352f71b6beede3
author Oleg Nesterov <oleg@redhat.com> 1238716697 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1238724299 -0700

reparent_thread: fix a zombie leak if /sbin/init ignores SIGCHLD

If /sbin/init ignores SIGCHLD and we re-parent a zombie, it is leaked.
reparent_thread() does do_notify_parent() which sets ->exit_signal = -1 in
this case.  This means that nobody except us can reap it, the detached
task is not visible to do_wait().

Change reparent_thread() to return a boolean (like __pthread_detach) to
indicate that the thread is dead and must be released.  Also change
forget_original_parent() to add the child to ptrace_dead list in this
case.

The naming becomes insane, the next patch does the cleanup.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>