io_uring/futex: always remove futex entry for cancel all

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: 194bb58 ("io_uring: add support for futex wake and wait")
Fixes: 8f35019 ("io_uring: add support for vectored futex waits")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: axboe

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;
 	}