diff options
| author | Jens Axboe <axboe@kernel.dk> | 2025-12-01 13:25:22 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2025-12-04 07:18:01 -0700 |
| commit | 84230ad2d2afbf0c44c32967e525c0ad92e26b4e (patch) | |
| tree | c7b2d88c30940c10ad0a51dcc3999769075e2e3e /io_uring | |
| parent | 559e608c46553c107dbba19dae0854af7b219400 (diff) | |
io_uring/poll: correctly handle io_poll_add() return value on update
When the core of io_uring was updated to handle completions
consistently and with fixed return codes, the POLL_REMOVE opcode
with updates got slightly broken. If a POLL_ADD is pending and
then POLL_REMOVE is used to update the events of that request, if that
update causes the POLL_ADD to now trigger, then that completion is lost
and a CQE is never posted.
Additionally, ensure that if an update does cause an existing POLL_ADD
to complete, that the completion value isn't always overwritten with
-ECANCELED. For that case, whatever io_poll_add() set the value to
should just be retained.
Cc: stable@vger.kernel.org
Fixes: 97b388d70b53 ("io_uring: handle completions in the core")
Reported-by: syzbot+641eec6b7af1f62f2b99@syzkaller.appspotmail.com
Tested-by: syzbot+641eec6b7af1f62f2b99@syzkaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring')
| -rw-r--r-- | io_uring/poll.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/io_uring/poll.c b/io_uring/poll.c index 8aa4e3a31e73..3f1d716dcfab 100644 --- a/io_uring/poll.c +++ b/io_uring/poll.c @@ -937,12 +937,17 @@ int io_poll_remove(struct io_kiocb *req, unsigned int issue_flags) ret2 = io_poll_add(preq, issue_flags & ~IO_URING_F_UNLOCKED); /* successfully updated, don't complete poll request */ - if (!ret2 || ret2 == -EIOCBQUEUED) + if (ret2 == IOU_ISSUE_SKIP_COMPLETE) goto out; + /* request completed as part of the update, complete it */ + else if (ret2 == IOU_COMPLETE) + goto complete; } - req_set_fail(preq); io_req_set_res(preq, -ECANCELED, 0); +complete: + if (preq->cqe.res < 0) + req_set_fail(preq); preq->io_task_work.func = io_req_task_complete; io_req_task_work_add(preq); out: |