Re: [PATCH 4.19 209/211] fuse: fix deadlock with aio poll and fuse_iqueue::waitq.lock

On Thu, Oct 03, 2019 at 05:54:35PM +0200, Greg Kroah-Hartman wrote:

static void queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req) {

• spin_lock(&fiq->waitq.lock);

• spin_lock(&fiq->lock); if (test_bit(FR_FINISHED, &req->flags)) {

• spin_unlock(&fiq->waitq.lock);
  

• spin_unlock(&fiq->lock);
  

  return; } if (list_empty(&req->intr_entry)) { list_add_tail(&req->intr_entry, &fiq->interrupts); wake_up_locked(&fiq->waitq); }

• spin_unlock(&fiq->waitq.lock);

• spin_unlock(&fiq->lock); kill_fasync(&fiq->fasync, SIGIO, POLL_IN);

}

This isn't backported correctly. wake_up_locked() needs to be changed to wake_up().

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index c0d59a86ada2e..6d39143cfa094 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -434,7 +434,7 @@ static void queue_interrupt(struct fuse_iqueue *fiq, struct fuse_req *req) } if (list_empty(&req->intr_entry)) { list_add_tail(&req->intr_entry, &fiq->interrupts); - wake_up_locked(&fiq->waitq); + wake_up(&fiq->waitq); } spin_unlock(&fiq->lock); kill_fasync(&fiq->fasync, SIGIO, POLL_IN);