Commit 1291cf41 authored Oct 30, 2005 by Oleg Nesterov Committed by Linus Torvalds Oct 30, 2005

[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>

parent f7232056

fs/exec.c

+13 −3

Original line number	Diff line number	Diff line
		@@ -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);
		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);

		/*