[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>
This commit is contained in:
Oleg Nesterov 2005-10-30 15:02:54 -08:00 committed by Linus Torvalds
parent f7232056bf
commit 1291cf4163

View File

@ -1460,11 +1460,21 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs)
current->fsuid = 0; /* Dump root private */
}
mm->dumpable = 0;
init_completion(&mm->core_done);
retval = -EAGAIN;
spin_lock_irq(&current->sighand->siglock);
current->signal->flags = SIGNAL_GROUP_EXIT;
current->signal->group_exit_code = exit_code;
if (!(current->signal->flags & SIGNAL_GROUP_EXIT)) {
current->signal->flags = SIGNAL_GROUP_EXIT;
current->signal->group_exit_code = exit_code;
retval = 0;
}
spin_unlock_irq(&current->sighand->siglock);
if (retval) {
up_write(&mm->mmap_sem);
goto fail;
}
init_completion(&mm->core_done);
coredump_wait(mm);
/*