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| author | Hao Xu <haoxu@linux.alibaba.com> | 2021-09-22 13:12:36 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2021-09-24 19:24:34 +0300 |
| commit | bd99c71bd14072ce2920f6d0c2fe43df072c653c (patch) | |
| tree | 2bfb3a10247a77a18deeb83f4f2387c9e76da197 | |
| parent | 87c1696655787895689618c8b63c5efe66b8f2ab (diff) | |
| download | linux-bd99c71bd14072ce2920f6d0c2fe43df072c653c.tar.xz | |
io_uring: fix race between poll completion and cancel_hash insertion
If poll arming and poll completion runs in parallel, there maybe races.
For instance, run io_poll_add in iowq and io_poll_task_func in original
context, then:
iowq original context
io_poll_add
vfs_poll
(interruption happens
tw queued to original
context) io_poll_task_func
generate cqe
del from cancel_hash[]
if !poll.done
insert to cancel_hash[]
The entry left in cancel_hash[], similar case for fast poll.
Fix it by set poll.done = true when del from cancel_hash[].
Fixes: 5082620fb2ca ("io_uring: terminate multishot poll for CQ ring overflow")
Signed-off-by: Hao Xu <haoxu@linux.alibaba.com>
Link: https://lore.kernel.org/r/20210922101238.7177-2-haoxu@linux.alibaba.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | fs/io_uring.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index e372d5b9f6dc..43530aae6180 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -5337,10 +5337,8 @@ static bool __io_poll_complete(struct io_kiocb *req, __poll_t mask) } if (req->poll.events & EPOLLONESHOT) flags = 0; - if (!io_cqring_fill_event(ctx, req->user_data, error, flags)) { - req->poll.done = true; + if (!io_cqring_fill_event(ctx, req->user_data, error, flags)) flags = 0; - } if (flags & IORING_CQE_F_MORE) ctx->cq_extra++; @@ -5371,6 +5369,7 @@ static void io_poll_task_func(struct io_kiocb *req, bool *locked) if (done) { io_poll_remove_double(req); hash_del(&req->hash_node); + req->poll.done = true; } else { req->result = 0; add_wait_queue(req->poll.head, &req->poll.wait); @@ -5508,6 +5507,7 @@ static void io_async_task_func(struct io_kiocb *req, bool *locked) hash_del(&req->hash_node); io_poll_remove_double(req); + apoll->poll.done = true; spin_unlock(&ctx->completion_lock); if (!READ_ONCE(apoll->poll.canceled)) |