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authorOleg Nesterov <oleg@tv-sign.ru>2005-10-30 15:02:54 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2005-10-30 17:37:25 -0800
commit1291cf4163d21f1b4999d697cbf68d38e7151c28 (patch)
tree0e1c3e3970216c769f91f6077b0e23d47d6fd333
parentf7232056bff5fe2d3bfeab35252a66ebaeb5bbde (diff)
[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>
-rw-r--r--fs/exec.c16
1 files changed, 13 insertions, 3 deletions
diff --git a/fs/exec.c b/fs/exec.c
index 6d9521636aa..10d493fea7c 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -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);
/*