Merge branch 'io_uring-5.8' into for-5.9/io_uring

Merge in io_uring-5.8 fixes, as changes/cleanups to how we do locked
mem accounting require a fixup, and only one of the spots are noticed
by git as the other merges cleanly. The flags fix from io_uring-5.8
also causes a merge conflict, the leak fix for recvmsg, the double poll
fix, and the link failure locking fix.

* io_uring-5.8:
  io_uring: fix lockup in io_fail_links()
  io_uring: fix ->work corruption with poll_add
  io_uring: missed req_init_async() for IOSQE_ASYNC
  io_uring: always allow drain/link/hardlink/async sqe flags
  io_uring: ensure double poll additions work with both request types
  io_uring: fix recvmsg memory leak with buffer selection
  io_uring: fix not initialised work->flags
  io_uring: fix missing msg_name assignment
  io_uring: account user memory freed when exit has been queued
  io_uring: fix memleak in io_sqe_files_register()
  io_uring: fix memleak in __io_sqe_files_update()
  io_uring: export cq overflow status to userspace
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -593,6 +593,7 @@ enum {
 
 struct async_poll {
 	struct io_poll_iocb	poll;
+	struct io_poll_iocb	*double_poll;
 	struct io_wq_work	work;
 };
 
@@ -1146,6 +1147,8 @@ static void io_prep_async_work(struct io_kiocb *req)
 {
 	const struct io_op_def *def = &io_op_defs[req->opcode];
 
+	io_req_init_async(req);
+
 	if (req->flags & REQ_F_ISREG) {
 		if (def->hash_reg_file)
 			io_wq_hash_work(&req->work, file_inode(req->file));
@@ -1337,6 +1340,7 @@ static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force)
 	if (cqe) {
 		clear_bit(0, &ctx->sq_check_overflow);
 		clear_bit(0, &ctx->cq_check_overflow);
+		ctx->rings->sq_flags &= ~IORING_SQ_CQ_OVERFLOW;
 	}
 	spin_unlock_irqrestore(&ctx->completion_lock, flags);
 	io_cqring_ev_posted(ctx);
@@ -1374,6 +1378,7 @@ static void __io_cqring_fill_event(struct io_kiocb *req, long res, long cflags)
 		if (list_empty(&ctx->cq_overflow_list)) {
 			set_bit(0, &ctx->sq_check_overflow);
 			set_bit(0, &ctx->cq_check_overflow);
+			ctx->rings->sq_flags |= IORING_SQ_CQ_OVERFLOW;
 		}
 		req->flags |= REQ_F_OVERFLOW;
 		refcount_inc(&req->refs);
@@ -3912,6 +3917,7 @@ static int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	if (req->flags & REQ_F_NEED_CLEANUP)
 		return 0;
 
+	io->msg.msg.msg_name = &io->msg.addr;
 	io->msg.iov = io->msg.fast_iov;
 	ret = sendmsg_copy_msghdr(&io->msg.msg, sr->msg, sr->msg_flags,
 					&io->msg.iov);
@@ -4093,6 +4099,7 @@ static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
 
 static int io_recvmsg_copy_hdr(struct io_kiocb *req, struct io_async_ctx *io)
 {
+	io->msg.msg.msg_name = &io->msg.addr;
 	io->msg.iov = io->msg.fast_iov;
 
 #ifdef CONFIG_COMPAT
@@ -4202,10 +4209,16 @@ static int io_recvmsg(struct io_kiocb *req, bool force_nonblock,
 
 		ret = __sys_recvmsg_sock(sock, &kmsg->msg, req->sr_msg.msg,
 						kmsg->uaddr, flags);
-		if (force_nonblock && ret == -EAGAIN)
-			return io_setup_async_msg(req, kmsg);
+		if (force_nonblock && ret == -EAGAIN) {
+			ret = io_setup_async_msg(req, kmsg);
+			if (ret != -EAGAIN)
+				kfree(kbuf);
+			return ret;
+		}
 		if (ret == -ERESTARTSYS)
 			ret = -EINTR;
+		if (kbuf)
+			kfree(kbuf);
 	}
 
 	if (kmsg && kmsg->iov != kmsg->fast_iov)
@@ -4492,9 +4505,9 @@ static bool io_poll_rewait(struct io_kiocb *req, struct io_poll_iocb *poll)
 	return false;
 }
 
-static void io_poll_remove_double(struct io_kiocb *req)
+static void io_poll_remove_double(struct io_kiocb *req, void *data)
 {
-	struct io_poll_iocb *poll = (struct io_poll_iocb *) req->io;
+	struct io_poll_iocb *poll = data;
 
 	lockdep_assert_held(&req->ctx->completion_lock);
 
@@ -4514,7 +4527,7 @@ static void io_poll_complete(struct io_kiocb *req, __poll_t mask, int error)
 {
 	struct io_ring_ctx *ctx = req->ctx;
 
-	io_poll_remove_double(req);
+	io_poll_remove_double(req, req->io);
 	req->poll.done = true;
 	io_cqring_fill_event(req, error ? error : mangle_poll(mask));
 	io_commit_cqring(ctx);
@@ -4552,21 +4565,21 @@ static int io_poll_double_wake(struct wait_queue_entry *wait, unsigned mode,
 			       int sync, void *key)
 {
 	struct io_kiocb *req = wait->private;
-	struct io_poll_iocb *poll = (struct io_poll_iocb *) req->io;
+	struct io_poll_iocb *poll = req->apoll->double_poll;
 	__poll_t mask = key_to_poll(key);
 
 	/* for instances that support it check for an event match first: */
 	if (mask && !(mask & poll->events))
 		return 0;
 
-	if (req->poll.head) {
+	if (poll && poll->head) {
 		bool done;
 
-		spin_lock(&req->poll.head->lock);
-		done = list_empty(&req->poll.wait.entry);
+		spin_lock(&poll->head->lock);
+		done = list_empty(&poll->wait.entry);
 		if (!done)
-			list_del_init(&req->poll.wait.entry);
-		spin_unlock(&req->poll.head->lock);
+			list_del_init(&poll->wait.entry);
+		spin_unlock(&poll->head->lock);
 		if (!done)
 			__io_async_wake(req, poll, mask, io_poll_task_func);
 	}
@@ -4586,7 +4599,8 @@ static void io_init_poll_iocb(struct io_poll_iocb *poll, __poll_t events,
 }
 
 static void __io_queue_proc(struct io_poll_iocb *poll, struct io_poll_table *pt,
-			    struct wait_queue_head *head)
+			    struct wait_queue_head *head,
+			    struct io_poll_iocb **poll_ptr)
 {
 	struct io_kiocb *req = pt->req;
 
@@ -4597,7 +4611,7 @@ static void __io_queue_proc(struct io_poll_iocb *poll, struct io_poll_table *pt,
 	 */
 	if (unlikely(poll->head)) {
 		/* already have a 2nd entry, fail a third attempt */
-		if (req->io) {
+		if (*poll_ptr) {
 			pt->error = -EINVAL;
 			return;
 		}
@@ -4609,7 +4623,7 @@ static void __io_queue_proc(struct io_poll_iocb *poll, struct io_poll_table *pt,
 		io_init_poll_iocb(poll, req->poll.events, io_poll_double_wake);
 		refcount_inc(&req->refs);
 		poll->wait.private = req;
-		req->io = (void *) poll;
+		*poll_ptr = poll;
 	}
 
 	pt->error = 0;
@@ -4625,8 +4639,9 @@ static void io_async_queue_proc(struct file *file, struct wait_queue_head *head,
 			       struct poll_table_struct *p)
 {
 	struct io_poll_table *pt = container_of(p, struct io_poll_table, pt);
+	struct async_poll *apoll = pt->req->apoll;
 
-	__io_queue_proc(&pt->req->apoll->poll, pt, head);
+	__io_queue_proc(&apoll->poll, pt, head, &apoll->double_poll);
 }
 
 static void io_async_task_func(struct callback_head *cb)
@@ -4646,6 +4661,7 @@ static void io_async_task_func(struct callback_head *cb)
 	if (hash_hashed(&req->hash_node))
 		hash_del(&req->hash_node);
 
+	io_poll_remove_double(req, apoll->double_poll);
 	spin_unlock_irq(&ctx->completion_lock);
 
 	/* restore ->work in case we need to retry again */
@@ -4657,6 +4673,7 @@ static void io_async_task_func(struct callback_head *cb)
 	else
 		__io_req_task_cancel(req, -ECANCELED);
 
+	kfree(apoll->double_poll);
 	kfree(apoll);
 }
 
@@ -4728,7 +4745,6 @@ static bool io_arm_poll_handler(struct io_kiocb *req)
 	struct async_poll *apoll;
 	struct io_poll_table ipt;
 	__poll_t mask, ret;
-	bool had_io;
 
 	if (!req->file || !file_can_poll(req->file))
 		return false;
@@ -4740,11 +4756,11 @@ static bool io_arm_poll_handler(struct io_kiocb *req)
 	apoll = kmalloc(sizeof(*apoll), GFP_ATOMIC);
 	if (unlikely(!apoll))
 		return false;
+	apoll->double_poll = NULL;
 
 	req->flags |= REQ_F_POLLED;
 	if (req->flags & REQ_F_WORK_INITIALIZED)
 		memcpy(&apoll->work, &req->work, sizeof(req->work));
-	had_io = req->io != NULL;
 
 	io_get_req_task(req);
 	req->apoll = apoll;
@@ -4762,13 +4778,11 @@ static bool io_arm_poll_handler(struct io_kiocb *req)
 	ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask,
 					io_async_wake);
 	if (ret) {
-		ipt.error = 0;
-		/* only remove double add if we did it here */
-		if (!had_io)
-			io_poll_remove_double(req);
+		io_poll_remove_double(req, apoll->double_poll);
 		spin_unlock_irq(&ctx->completion_lock);
 		if (req->flags & REQ_F_WORK_INITIALIZED)
 			memcpy(&req->work, &apoll->work, sizeof(req->work));
+		kfree(apoll->double_poll);
 		kfree(apoll);
 		return false;
 	}
@@ -4799,11 +4813,13 @@ static bool io_poll_remove_one(struct io_kiocb *req)
 	bool do_complete;
 
 	if (req->opcode == IORING_OP_POLL_ADD) {
-		io_poll_remove_double(req);
+		io_poll_remove_double(req, req->io);
 		do_complete = __io_poll_remove_one(req, &req->poll);
 	} else {
 		struct async_poll *apoll = req->apoll;
 
+		io_poll_remove_double(req, apoll->double_poll);
+
 		/* non-poll requests have submit ref still */
 		do_complete = __io_poll_remove_one(req, &apoll->poll);
 		if (do_complete) {
@@ -4816,6 +4832,7 @@ static bool io_poll_remove_one(struct io_kiocb *req)
 			if (req->flags & REQ_F_WORK_INITIALIZED)
 				memcpy(&req->work, &apoll->work,
 				       sizeof(req->work));
+			kfree(apoll->double_poll);
 			kfree(apoll);
 		}
 	}
@@ -4915,7 +4932,7 @@ static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head,
 {
 	struct io_poll_table *pt = container_of(p, struct io_poll_table, pt);
 
-	__io_queue_proc(&pt->req->poll, pt, head);
+	__io_queue_proc(&pt->req->poll, pt, head, (struct io_poll_iocb **) &pt->req->io);
 }
 
 static int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
@@ -4948,6 +4965,10 @@ static int io_poll_add(struct io_kiocb *req)
 	struct io_poll_table ipt;
 	__poll_t mask;
 
+	/* ->work is in union with hash_node and others */
+	io_req_work_drop_env(req);
+	req->flags &= ~REQ_F_WORK_INITIALIZED;
+
 	INIT_HLIST_NODE(&req->hash_node);
 	INIT_LIST_HEAD(&req->list);
 	ipt.pt._qproc = io_poll_queue_proc;
@@ -5027,7 +5048,9 @@ static int io_timeout_remove_prep(struct io_kiocb *req,
 {
 	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
 		return -EINVAL;
-	if (sqe->flags || sqe->ioprio || sqe->buf_index || sqe->len)
+	if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
+		return -EINVAL;
+	if (sqe->ioprio || sqe->buf_index || sqe->len)
 		return -EINVAL;
 
 	req->timeout.addr = READ_ONCE(sqe->addr);
@@ -5203,8 +5226,9 @@ static int io_async_cancel_prep(struct io_kiocb *req,
 {
 	if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
 		return -EINVAL;
-	if (sqe->flags || sqe->ioprio || sqe->off || sqe->len ||
-	    sqe->cancel_flags)
+	if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
+		return -EINVAL;
+	if (sqe->ioprio || sqe->off || sqe->len || sqe->cancel_flags)
 		return -EINVAL;
 
 	req->cancel.addr = READ_ONCE(sqe->addr);
@@ -5222,7 +5246,9 @@ static int io_async_cancel(struct io_kiocb *req)
 static int io_files_update_prep(struct io_kiocb *req,
 				const struct io_uring_sqe *sqe)
 {
-	if (sqe->flags || sqe->ioprio || sqe->rw_flags)
+	if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
+		return -EINVAL;
+	if (sqe->ioprio || sqe->rw_flags)
 		return -EINVAL;
 
 	req->files_update.offset = READ_ONCE(sqe->off);
@@ -5996,6 +6022,7 @@ static void io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 		 * Never try inline submit of IOSQE_ASYNC is set, go straight
 		 * to async execution.
 		 */
+		io_req_init_async(req);
 		req->work.flags |= IO_WQ_WORK_CONCURRENT;
 		io_queue_async_work(req);
 	} else {
@@ -6372,9 +6399,9 @@ static int io_sq_thread(void *data)
 			}
 
 			/* Tell userspace we may need a wakeup call */
+			spin_lock_irq(&ctx->completion_lock);
 			ctx->rings->sq_flags |= IORING_SQ_NEED_WAKEUP;
-			/* make sure to read SQ tail after writing flags */
-			smp_mb();
+			spin_unlock_irq(&ctx->completion_lock);
 
 			to_submit = io_sqring_entries(ctx);
 			if (!to_submit || ret == -EBUSY) {
@@ -6391,13 +6418,17 @@ static int io_sq_thread(void *data)
 				schedule();
 				finish_wait(&ctx->sqo_wait, &wait);
 
+				spin_lock_irq(&ctx->completion_lock);
 				ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP;
+				spin_unlock_irq(&ctx->completion_lock);
 				ret = 0;
 				continue;
 			}
 			finish_wait(&ctx->sqo_wait, &wait);
 
+			spin_lock_irq(&ctx->completion_lock);
 			ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP;
+			spin_unlock_irq(&ctx->completion_lock);
 		}
 
 		mutex_lock(&ctx->uring_lock);
@@ -6982,6 +7013,7 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
 		for (i = 0; i < nr_tables; i++)
 			kfree(ctx->file_data->table[i].files);
 
+		percpu_ref_exit(&ctx->file_data->refs);
 		kfree(ctx->file_data->table);
 		kfree(ctx->file_data);
 		ctx->file_data = NULL;
@@ -7134,9 +7166,11 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx,
 			}
 			table->files[index] = file;
 			err = io_sqe_file_register(ctx, file, i);
-			if (err)
+			if (err) {
+				fput(file);
 				break;
 			}
+		}
 		nr_args--;
 		done++;
 		up->offset++;
@@ -7665,8 +7699,6 @@ static void io_ring_ctx_free(struct io_ring_ctx *ctx)
 	io_mem_free(ctx->sq_sqes);
 
 	percpu_ref_exit(&ctx->refs);
-	io_unaccount_mem(ctx, ring_pages(ctx->sq_entries, ctx->cq_entries),
-			 ACCT_LOCKED);
 	free_uid(ctx->user);
 	put_cred(ctx->creds);
 	kfree(ctx->cancel_hash);
@@ -7748,6 +7780,15 @@ static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
 		io_cqring_overflow_flush(ctx, true);
 	io_iopoll_try_reap_events(ctx);
 	idr_for_each(&ctx->personality_idr, io_remove_personalities, ctx);
+
+	/*
+	 * Do this upfront, so we won't have a grace period where the ring
+	 * is closed but resources aren't reaped yet. This can cause
+	 * spurious failure in setting up a new ring.
+	 */
+	io_unaccount_mem(ctx, ring_pages(ctx->sq_entries, ctx->cq_entries),
+			 ACCT_LOCKED);
+
 	INIT_WORK(&ctx->exit_work, io_ring_exit_work);
 	queue_work(system_wq, &ctx->exit_work);
 }
@@ -7807,6 +7848,7 @@ static void io_uring_cancel_files(struct io_ring_ctx *ctx,
 			if (list_empty(&ctx->cq_overflow_list)) {
 				clear_bit(0, &ctx->sq_check_overflow);
 				clear_bit(0, &ctx->cq_check_overflow);
+				ctx->rings->sq_flags &= ~IORING_SQ_CQ_OVERFLOW;
 			}
 			spin_unlock_irq(&ctx->completion_lock);
 

include/uapi/linux/io_uring.h

@@ -198,6 +198,7 @@ struct io_sqring_offsets {
  * sq_ring->flags
  */
 #define IORING_SQ_NEED_WAKEUP	(1U << 0) /* needs io_uring_enter wakeup */
+#define IORING_SQ_CQ_OVERFLOW	(1U << 1) /* CQ ring is overflown */
 
 struct io_cqring_offsets {
 	__u32 head;