[PATCH 6.0 259/314] io_uring: fix multishot recv request leaks

[Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>]

From: Pavel Begunkov <asml.silence@xxxxxxxxx>

commit 100d6b17c06ee4c2b42fdddf0fe4ab77c86eb77e upstream.

Having REQ_F_POLLED set doesn't guarantee that the request is
executed as a multishot from the polling path. Fortunately for us, if
the code thinks it's multishot issue when it's not, it can only ask to
skip completion so leaking the request. Use issue_flags to mark
multipoll issues.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 1300ebb20286b ("io_uring: multishot recv")
Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
Link: https://lore.kernel.org/r/37762040ba9c52b81b92a2f5ebfd4ee484088951.1668710222.git.asml.silence@xxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 io_uring/net.c |   16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -66,8 +66,6 @@ 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);
@@ -558,7 +556,8 @@ static inline void io_recv_prep_retry(st
  * 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);
@@ -581,7 +580,7 @@ static inline bool io_recv_finish(struct
 
 	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;
@@ -740,8 +739,7 @@ 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;
 			}
@@ -770,7 +768,7 @@ 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) {
@@ -836,7 +834,7 @@ 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;
 			}
@@ -869,7 +867,7 @@ 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;