io_uring/futex: always remove futex entry for cancel all

[ Upstream commit 30dab608c3cb99c2a05b76289fd05551703979ae ]

We know the request is either being removed, or already in the process of
being removed through task_work, so we can delete it from our futex list
upfront. This is important for remove all conditions, as we otherwise
will find it multiple times and prevent cancelation progress.

Cc: stable@vger.kernel.org
Fixes: 194bb58c6090 ("io_uring: add support for futex wake and wait")
Fixes: 8f350194d5cf ("io_uring: add support for vectored futex waits")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/io_uring/futex.c b/io_uring/futex.c
index 3c3575303c3d0033e3d5d537aa094f5150fa244d..792a03df58deac775d9c0ce05d9a77f63df0545f 100644 (file)
--- a/io_uring/futex.c
+++ b/io_uring/futex.c
@@ -159,6 +159,7 @@ bool io_futex_remove_all(struct io_ring_ctx *ctx, struct task_struct *task,
        hlist_for_each_entry_safe(req, tmp, &ctx->futex_list, hash_node) {
                if (!io_match_task_safe(req, task, cancel_all))
                        continue;
+               hlist_del_init(&req->hash_node);
                __io_futex_cancel(ctx, req);
                found = true;
        }