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

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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>

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This commit is contained in:

Oleg Nesterov 2009-04-02 16:58:17 -07:00 • committed by Linus Torvalds

parent b1442b055c

commit 7f5d3652d4

1 changed files with 17 additions and 5 deletions

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kernel/exit.c

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