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authorJens Axboe2022-03-21 19:03:24 -0600
committerJens Axboe2022-03-21 19:03:24 -0600
commit61bc84c4008812d784c398cfb54118c1ba396dfc (patch)
tree7f96500cac4217995f120dbc129f2ea2145a87bb /fs/io_uring.c
parent649bb75d19c93f5459f450191953dff4825fda3e (diff)
io_uring: remove poll entry from list when canceling all
When the ring is exiting, as part of the shutdown, poll requests are removed. But io_poll_remove_all() does not remove entries when finding them, and since completions are done out-of-band, we can find and remove the same entry multiple times. We do guard the poll execution by poll ownership, but that does not exclude us from reissuing a new one once the previous removal ownership goes away. This can race with poll execution as well, where we then end up seeing req->apoll be NULL because a previous task_work requeue finished the request. Remove the poll entry when we find it and get ownership of it. This prevents multiple invocations from finding it. Fixes: aa43477b0402 ("io_uring: poll rework") Reported-by: Dylan Yudaken <dylany@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs/io_uring.c')
-rw-r--r--fs/io_uring.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 48f4540d7dd5..53bd71363a44 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -6275,6 +6275,7 @@ static __cold bool io_poll_remove_all(struct io_ring_ctx *ctx,
list = &ctx->cancel_hash[i];
hlist_for_each_entry_safe(req, tmp, list, hash_node) {
if (io_match_task_safe(req, tsk, cancel_all)) {
+ hlist_del_init(&req->hash_node);
io_poll_cancel_req(req);
found = true;
}