diff options
| author | Xiaoguang Wang | 2020-12-14 23:49:41 +0800 |
|---|---|---|
| committer | Jens Axboe | 2020-12-22 17:14:53 -0700 |
| commit | c07e6719511e77c4b289f62bfe96423eb6ea061d (patch) | |
| tree | 1a6848f00dec676fba687d55aae5da8cab9af522 /fs | |
| parent | 9faadcc8abe4b83d0263216dc3a6321d5bbd616b (diff) | |
io_uring: hold uring_lock while completing failed polled io in io_wq_submit_work()
io_iopoll_complete() does not hold completion_lock to complete polled io,
so in io_wq_submit_work(), we can not call io_req_complete() directly, to
complete polled io, otherwise there maybe concurrent access to cqring,
defer_list, etc, which is not safe. Commit dad1b1242fd5 ("io_uring: always
let io_iopoll_complete() complete polled io") has fixed this issue, but
Pavel reported that IOPOLL apart from rw can do buf reg/unreg requests(
IORING_OP_PROVIDE_BUFFERS or IORING_OP_REMOVE_BUFFERS), so the fix is not
good.
Given that io_iopoll_complete() is always called under uring_lock, so here
for polled io, we can also get uring_lock to fix this issue.
Fixes: dad1b1242fd5 ("io_uring: always let io_iopoll_complete() complete polled io")
Cc: <stable@vger.kernel.org> # 5.5+
Signed-off-by: Xiaoguang Wang <xiaoguang.wang@linux.alibaba.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
[axboe: don't deref 'req' after completing it']
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/io_uring.c | 29 |
1 files changed, 19 insertions, 10 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index 7c0b77d49cd2..7e35283fc0b1 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -6332,19 +6332,28 @@ static struct io_wq_work *io_wq_submit_work(struct io_wq_work *work) } if (ret) { + struct io_ring_ctx *lock_ctx = NULL; + + if (req->ctx->flags & IORING_SETUP_IOPOLL) + lock_ctx = req->ctx; + /* - * io_iopoll_complete() does not hold completion_lock to complete - * polled io, so here for polled io, just mark it done and still let - * io_iopoll_complete() complete it. + * io_iopoll_complete() does not hold completion_lock to + * complete polled io, so here for polled io, we can not call + * io_req_complete() directly, otherwise there maybe concurrent + * access to cqring, defer_list, etc, which is not safe. Given + * that io_iopoll_complete() is always called under uring_lock, + * so here for polled io, we also get uring_lock to complete + * it. */ - if (req->ctx->flags & IORING_SETUP_IOPOLL) { - struct kiocb *kiocb = &req->rw.kiocb; + if (lock_ctx) + mutex_lock(&lock_ctx->uring_lock); - kiocb_done(kiocb, ret, NULL); - } else { - req_set_fail_links(req); - io_req_complete(req, ret); - } + req_set_fail_links(req); + io_req_complete(req, ret); + + if (lock_ctx) + mutex_unlock(&lock_ctx->uring_lock); } return io_steal_work(req); |