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Oleg Nesterov authored
Pointed out by Roland. The bug was recently introduced by me in "forget_original_parent: split out the un-ptrace part", commit 39c626ae. Since that patch we have a window after exit_ptrace() drops tasklist and before forget_original_parent() takes it again. In this window the child can do ptrace(PTRACE_TRACEME) and nobody can untrace this child after that. Change ptrace_traceme() to not attach to the exiting ->real_parent. We don't report the error in this case, we pretend we attach right before ->real_parent calls exit_ptrace() which should untrace us anyway. Signed-off-by:
Oleg Nesterov <oleg@redhat.com> Acked-by:
Roland McGrath <roland@redhat.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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