diff options
| author |   Pavel Begunkov <asml.silence@gmail.com> | 2021-07-20 10:50:44 +0100 |
|---|---|---|
| committer |   Jens Axboe <axboe@kernel.dk> | 2021-07-20 07:50:42 -0600 |
| commit | 46fee9ab02cb24979bbe07631fc3ae95ae08aa3e (patch) | |
| tree | 77a311f9ff1e7b4d5e66deb1ecb42acf311fff44 /fs | |
| parent | io_uring: explicitly count entries for poll reqs (diff) | |
| download | linux-dev-46fee9ab02cb24979bbe07631fc3ae95ae08aa3e.tar.xz linux-dev-46fee9ab02cb24979bbe07631fc3ae95ae08aa3e.zip | |
io_uring: remove double poll entry on arm failure
__io_queue_proc() can enqueue both poll entries and still fail
afterwards, so the callers trying to cancel it should also try to remove
the second poll entry (if any).
For example, it may leave the request alive referencing a io_uring
context but not accessible for cancellation:
[ 282.599913][ T1620] task:iou-sqp-23145 state:D stack:28720 pid:23155 ppid: 8844 flags:0x00004004
[ 282.609927][ T1620] Call Trace:
[ 282.613711][ T1620] __schedule+0x93a/0x26f0
[ 282.634647][ T1620] schedule+0xd3/0x270
[ 282.638874][ T1620] io_uring_cancel_generic+0x54d/0x890
[ 282.660346][ T1620] io_sq_thread+0xaac/0x1250
[ 282.696394][ T1620] ret_from_fork+0x1f/0x30
Cc: stable@vger.kernel.org
Fixes: 18bceab101add ("io_uring: allow POLL_ADD with double poll_wait() users")
Reported-and-tested-by: syzbot+ac957324022b7132accf@syzkaller.appspotmail.com
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/0ec1228fc5eda4cb524eeda857da8efdc43c331c.1626774457.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/io_uring.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index 6668902cf50c..6486b54a0f62 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -5113,6 +5113,8 @@ static __poll_t __io_arm_poll_handler(struct io_kiocb *req, ipt->error = -EINVAL; spin_lock_irq(&ctx->completion_lock); + if (ipt->error) + io_poll_remove_double(req); if (likely(poll->head)) { spin_lock(&poll->head->lock); if (unlikely(list_empty(&poll->wait.entry))) { |