Merge tag 'io_uring-6.10-20240614' of git://git.kernel.dk/linux

Pull io_uring fixes from Jens Axboe:
 "Two fixes from Pavel headed to stable:

   - Ensure that the task state is correct before attempting to grab a
     mutex

   - Split cancel sequence flag into a separate variable, as it can get
     set by someone not owning the request (but holding the ctx lock)"

* tag 'io_uring-6.10-20240614' of git://git.kernel.dk/linux:
  io_uring: fix cancellation overwriting req->flags
  io_uring/rsrc: don't lock while !TASK_RUNNING

Author: torvalds

include/linux/io_uring_types.h

@@ -648,7 +648,7 @@ struct io_kiocb {
 	struct io_rsrc_node		*rsrc_node;
 
 	atomic_t			refs;
-	atomic_t			poll_refs;
+	bool				cancel_seq_set;
 	struct io_task_work		io_task_work;
 	/* for polled requests, i.e. IORING_OP_POLL_ADD and async armed poll */
 	struct hlist_node		hash_node;
@@ -657,6 +657,7 @@ struct io_kiocb {
 	/* opcode allocated if it needs to store data for async defer */
 	void				*async_data;
 	/* linked requests, IFF REQ_F_HARDLINK or REQ_F_LINK are set */
+	atomic_t			poll_refs;
 	struct io_kiocb			*link;
 	/* custom credentials, valid IFF REQ_F_CREDS is set */
 	const struct cred		*creds;

io_uring/cancel.h

@@ -27,10 +27,10 @@ bool io_cancel_req_match(struct io_kiocb *req, struct io_cancel_data *cd);
 
 static inline bool io_cancel_match_sequence(struct io_kiocb *req, int sequence)
 {
-	if ((req->flags & REQ_F_CANCEL_SEQ) && sequence == req->work.cancel_seq)
+	if (req->cancel_seq_set && sequence == req->work.cancel_seq)
 		return true;
 
-	req->flags |= REQ_F_CANCEL_SEQ;
+	req->cancel_seq_set = true;
 	req->work.cancel_seq = sequence;
 	return false;
 }

io_uring/io_uring.c

@@ -2058,6 +2058,7 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
 	req->file = NULL;
 	req->rsrc_node = NULL;
 	req->task = current;
+	req->cancel_seq_set = false;
 
 	if (unlikely(opcode >= IORING_OP_LAST)) {
 		req->opcode = 0;

io_uring/rsrc.c

@@ -249,6 +249,7 @@ __cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data,
 
 		ret = io_run_task_work_sig(ctx);
 		if (ret < 0) {
+			__set_current_state(TASK_RUNNING);
 			mutex_lock(&ctx->uring_lock);
 			if (list_empty(&ctx->rsrc_ref_list))
 				ret = 0;