[PATCH] fix de_thread() vs do_coredump() deadlock
de_thread() sends SIGKILL to all sub-threads and waits them to die in 'D' state. It is possible that one of the threads already dequeued coredump signal. When de_thread() unlocks ->sighand->lock that thread can enter do_coredump()->coredump_wait() and cause a deadlock. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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16
fs/exec.c
16
fs/exec.c
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@ -1460,11 +1460,21 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs)
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current->fsuid = 0; /* Dump root private */
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}
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mm->dumpable = 0;
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init_completion(&mm->core_done);
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retval = -EAGAIN;
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spin_lock_irq(¤t->sighand->siglock);
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current->signal->flags = SIGNAL_GROUP_EXIT;
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current->signal->group_exit_code = exit_code;
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if (!(current->signal->flags & SIGNAL_GROUP_EXIT)) {
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current->signal->flags = SIGNAL_GROUP_EXIT;
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current->signal->group_exit_code = exit_code;
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retval = 0;
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}
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spin_unlock_irq(¤t->sighand->siglock);
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if (retval) {
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up_write(&mm->mmap_sem);
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goto fail;
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}
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init_completion(&mm->core_done);
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coredump_wait(mm);
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/*
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