fuse: fix race between interrupt and resend

After commit f8fce75fedf7 ("fuse: clear intr_entry in fuse_resend and
fuse_remove_pending_req") the WARN_ON(!list_empty(&req->intr_entry)) in
fuse_request_free() still triggers due to the following race:

In request_wait_answer()
  if (test_bit(FR_SENT, &req->flags)) -> returns true

In fuse_chan_resend()
  clear_bit(FR_SENT, &req->flags)

In request_wait_answer()
  queue_interrupt(req)

Fix by:

 - move clearing FR_SENT inside fpq->lock

 - move setting FR_PENDING inside fiq->lock

 - recheck FR_SENT after acquiring fiq->lock in fuse_dev_queue_interrupt()

Reported-by: zdi-disclosures@trendmicro.com
Fixes: f8fce75fedf7 ("fuse: clear intr_entry in fuse_resend and fuse_remove_pending_req")
Cc: stable@vger.kernel.org # 6.9
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

0 files changed, 0 insertions, 0 deletions