Commit d632c44d authored by Mike Rapoport's avatar Mike Rapoport Committed by Greg Kroah-Hartman

userfaultfd: non-cooperative: flush event_wqh at release time

commit 5a18b64e upstream.

There may still be threads waiting on event_wqh at the time the
userfault file descriptor is closed.  Flush the events wait-queue to
prevent waiting threads from hanging.

Link: http://lkml.kernel.org/r/1501398127-30419-1-git-send-email-rppt@linux.vnet.ibm.com
Fixes: 9cd75c3c ("userfaultfd: non-cooperative: add ability to report
non-PF events from uffd descriptor")
Signed-off-by: default avatarMike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 57f79327
...@@ -851,6 +851,9 @@ static int userfaultfd_release(struct inode *inode, struct file *file) ...@@ -851,6 +851,9 @@ static int userfaultfd_release(struct inode *inode, struct file *file)
__wake_up_locked_key(&ctx->fault_wqh, TASK_NORMAL, &range); __wake_up_locked_key(&ctx->fault_wqh, TASK_NORMAL, &range);
spin_unlock(&ctx->fault_pending_wqh.lock); spin_unlock(&ctx->fault_pending_wqh.lock);
/* Flush pending events that may still wait on event_wqh */
wake_up_all(&ctx->event_wqh);
wake_up_poll(&ctx->fd_wqh, POLLHUP); wake_up_poll(&ctx->fd_wqh, POLLHUP);
userfaultfd_ctx_put(ctx); userfaultfd_ctx_put(ctx);
return 0; return 0;
......
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