Merge tag 'io_uring-6.1-2022-11-18' of git://git.kernel.dk/linux

Pull io_uring fixes from Jens Axboe:
 "This is mostly fixing issues around the poll rework, but also two
  tweaks for the multishot handling for accept and receive.

  All stable material"

* tag 'io_uring-6.1-2022-11-18' of git://git.kernel.dk/linux:
  io_uring: disallow self-propelled ring polling
  io_uring: fix multishot recv request leaks
  io_uring: fix multishot accept request leaks
  io_uring: fix tw losing poll events
  io_uring: update res mask in io_poll_check_events

5 files changed, 27 insertions, 17 deletions

diff --git a/include/linux/io_uring.h b/include/linux/io_uring.h
index 43bc8a2edccf..0ded9e271523 100644
--- a/include/linux/io_uring.h
+++ b/include/linux/io_uring.h
@@ -16,6 +16,9 @@ enum io_uring_cmd_flags {
 	IO_URING_F_SQE128		= 4,
 	IO_URING_F_CQE32		= 8,
 	IO_URING_F_IOPOLL		= 16,
+
+	/* the request is executed from poll, it should not be freed */
+	IO_URING_F_MULTISHOT		= 32,
 };
 
 struct io_uring_cmd {
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 4a1e482747cc..8840cf3e20f2 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -1768,7 +1768,7 @@ int io_poll_issue(struct io_kiocb *req, bool *locked)
 	io_tw_lock(req->ctx, locked);
 	if (unlikely(req->task->flags & PF_EXITING))
 		return -EFAULT;
-	return io_issue_sqe(req, IO_URING_F_NONBLOCK);
+	return io_issue_sqe(req, IO_URING_F_NONBLOCK|IO_URING_F_MULTISHOT);
 }
 
 struct io_wq_work *io_wq_free_work(struct io_wq_work *work)
diff --git a/io_uring/io_uring.h b/io_uring/io_uring.h
index e99a79f2df9b..cef5ff924e63 100644
--- a/io_uring/io_uring.h
+++ b/io_uring/io_uring.h
@@ -17,8 +17,8 @@ enum {
 	IOU_ISSUE_SKIP_COMPLETE	= -EIOCBQUEUED,
 
 	/*
-	 * Intended only when both REQ_F_POLLED and REQ_F_APOLL_MULTISHOT
-	 * are set to indicate to the poll runner that multishot should be
+	 * Intended only when both IO_URING_F_MULTISHOT is passed
+	 * to indicate to the poll runner that multishot should be
 	 * removed and the result is set on req->cqe.res.
 	 */
 	IOU_STOP_MULTISHOT	= -ECANCELED,
diff --git a/io_uring/net.c b/io_uring/net.c
index 15dea91625e2..ab83da7e80f0 100644
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -67,8 +67,6 @@ struct io_sr_msg {
 	struct io_kiocb 		*notif;
 };
 
-#define IO_APOLL_MULTI_POLLED (REQ_F_APOLL_MULTISHOT | REQ_F_POLLED)
-
 int io_shutdown_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 {
 	struct io_shutdown *shutdown = io_kiocb_to_cmd(req, struct io_shutdown);
@@ -591,7 +589,8 @@ static inline void io_recv_prep_retry(struct io_kiocb *req)
  * again (for multishot).
  */
 static inline bool io_recv_finish(struct io_kiocb *req, int *ret,
-				  unsigned int cflags, bool mshot_finished)
+				  unsigned int cflags, bool mshot_finished,
+				  unsigned issue_flags)
 {
 	if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
 		io_req_set_res(req, *ret, cflags);
@@ -614,7 +613,7 @@ static inline bool io_recv_finish(struct io_kiocb *req, int *ret,
 
 	io_req_set_res(req, *ret, cflags);
 
-	if (req->flags & REQ_F_POLLED)
+	if (issue_flags & IO_URING_F_MULTISHOT)
 		*ret = IOU_STOP_MULTISHOT;
 	else
 		*ret = IOU_OK;
@@ -773,8 +772,7 @@ retry_multishot:
 	if (ret < min_ret) {
 		if (ret == -EAGAIN && force_nonblock) {
 			ret = io_setup_async_msg(req, kmsg, issue_flags);
-			if (ret == -EAGAIN && (req->flags & IO_APOLL_MULTI_POLLED) ==
-					       IO_APOLL_MULTI_POLLED) {
+			if (ret == -EAGAIN && (issue_flags & IO_URING_F_MULTISHOT)) {
 				io_kbuf_recycle(req, issue_flags);
 				return IOU_ISSUE_SKIP_COMPLETE;
 			}
@@ -803,7 +801,7 @@ retry_multishot:
 	if (kmsg->msg.msg_inq)
 		cflags |= IORING_CQE_F_SOCK_NONEMPTY;
 
-	if (!io_recv_finish(req, &ret, cflags, mshot_finished))
+	if (!io_recv_finish(req, &ret, cflags, mshot_finished, issue_flags))
 		goto retry_multishot;
 
 	if (mshot_finished) {
@@ -869,7 +867,7 @@ retry_multishot:
 	ret = sock_recvmsg(sock, &msg, flags);
 	if (ret < min_ret) {
 		if (ret == -EAGAIN && force_nonblock) {
-			if ((req->flags & IO_APOLL_MULTI_POLLED) == IO_APOLL_MULTI_POLLED) {
+			if (issue_flags & IO_URING_F_MULTISHOT) {
 				io_kbuf_recycle(req, issue_flags);
 				return IOU_ISSUE_SKIP_COMPLETE;
 			}
@@ -902,7 +900,7 @@ out_free:
 	if (msg.msg_inq)
 		cflags |= IORING_CQE_F_SOCK_NONEMPTY;
 
-	if (!io_recv_finish(req, &ret, cflags, ret <= 0))
+	if (!io_recv_finish(req, &ret, cflags, ret <= 0, issue_flags))
 		goto retry_multishot;
 
 	return ret;
@@ -1289,8 +1287,7 @@ retry:
 			 * return EAGAIN to arm the poll infra since it
 			 * has already been done
 			 */
-			if ((req->flags & IO_APOLL_MULTI_POLLED) ==
-			    IO_APOLL_MULTI_POLLED)
+			if (issue_flags & IO_URING_F_MULTISHOT)
 				ret = IOU_ISSUE_SKIP_COMPLETE;
 			return ret;
 		}
@@ -1315,9 +1312,7 @@ retry:
 		goto retry;
 
 	io_req_set_res(req, ret, 0);
-	if (req->flags & REQ_F_POLLED)
-		return IOU_STOP_MULTISHOT;
-	return IOU_OK;
+	return (issue_flags & IO_URING_F_MULTISHOT) ? IOU_STOP_MULTISHOT : IOU_OK;
 }
 
 int io_socket_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
diff --git a/io_uring/poll.c b/io_uring/poll.c
index f500506984ec..055632e9092a 100644
--- a/io_uring/poll.c
+++ b/io_uring/poll.c
@@ -228,6 +228,13 @@ static int io_poll_check_events(struct io_kiocb *req, bool *locked)
 			return IOU_POLL_DONE;
 		if (v & IO_POLL_CANCEL_FLAG)
 			return -ECANCELED;
+		/*
+		 * cqe.res contains only events of the first wake up
+		 * and all others are be lost. Redo vfs_poll() to get
+		 * up to date state.
+		 */
+		if ((v & IO_POLL_REF_MASK) != 1)
+			req->cqe.res = 0;
 
 		/* the mask was stashed in __io_poll_execute */
 		if (!req->cqe.res) {
@@ -239,6 +246,8 @@ static int io_poll_check_events(struct io_kiocb *req, bool *locked)
 			continue;
 		if (req->apoll_events & EPOLLONESHOT)
 			return IOU_POLL_DONE;
+		if (io_is_uring_fops(req->file))
+			return IOU_POLL_DONE;
 
 		/* multishot, just fill a CQE and proceed */
 		if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
@@ -258,6 +267,9 @@ static int io_poll_check_events(struct io_kiocb *req, bool *locked)
 				return ret;
 		}
 
+		/* force the next iteration to vfs_poll() */
+		req->cqe.res = 0;
+
 		/*
 		 * Release all references, retry if someone tried to restart
 		 * task_work while we were executing it.