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authorPavel Begunkov <asml.silence@gmail.com>2022-11-17 21:40:15 +0300
committerJens Axboe <axboe@kernel.dk>2022-11-17 22:33:33 +0300
commit539bcb57da2f58886d7d5c17134236b0ec9cd15d (patch)
tree5ecb26a02405a4a11e15704798d203e36743e297 /io_uring
parentb98186aee22fa593bc8c6b2c5d839c2ee518bc8c (diff)
downloadlinux-539bcb57da2f58886d7d5c17134236b0ec9cd15d.tar.xz
io_uring: fix tw losing poll events
We may never try to process a poll wake and its mask if there was multiple wake ups racing for queueing up a tw. Force io_poll_check_events() to update the mask by vfs_poll(). Cc: stable@vger.kernel.org Fixes: aa43477b04025 ("io_uring: poll rework") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/00344d60f8b18907171178d7cf598de71d127b0b.1668710222.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring')
-rw-r--r--io_uring/poll.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/io_uring/poll.c b/io_uring/poll.c
index 90920abf91ff..c34019b18211 100644
--- a/io_uring/poll.c
+++ b/io_uring/poll.c
@@ -228,6 +228,13 @@ static int io_poll_check_events(struct io_kiocb *req, bool *locked)
return IOU_POLL_DONE;
if (v & IO_POLL_CANCEL_FLAG)
return -ECANCELED;
+ /*
+ * cqe.res contains only events of the first wake up
+ * and all others are be lost. Redo vfs_poll() to get
+ * up to date state.
+ */
+ if ((v & IO_POLL_REF_MASK) != 1)
+ req->cqe.res = 0;
/* the mask was stashed in __io_poll_execute */
if (!req->cqe.res) {