FAILED: patch "[PATCH] io_uring/net: fix sr->len for IORING_OP_RECV with MSG_WAITALL" failed to apply to 5.15-stable tree

[<gregkh@xxxxxxxxxxxxxxxxxxx>]

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 72bd80252feeb3bef8724230ee15d9f7ab541c6e
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2024021339-flick-facsimile-65c3@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

72bd80252fee ("io_uring/net: fix sr->len for IORING_OP_RECV with MSG_WAITALL and buffers")
f9ead18c1058 ("io_uring: split network related opcodes into its own file")
e0da14def1ee ("io_uring: move statx handling to its own file")
a9c210cebe13 ("io_uring: move epoll handler to its own file")
4cf90495281b ("io_uring: add a dummy -EOPNOTSUPP prep handler")
99f15d8d6136 ("io_uring: move uring_cmd handling to its own file")
cd40cae29ef8 ("io_uring: split out open/close operations")
453b329be5ea ("io_uring: separate out file table handling code")
f4c163dd7d4b ("io_uring: split out fadvise/madvise operations")
0d5847274037 ("io_uring: split out fs related sync/fallocate functions")
531113bbd5bf ("io_uring: split out splice related operations")
11aeb71406dd ("io_uring: split out filesystem related operations")
e28683bdfc2f ("io_uring: move nop into its own file")
5e2a18d93fec ("io_uring: move xattr related opcodes to its own file")
97b388d70b53 ("io_uring: handle completions in the core")
de23077eda61 ("io_uring: set completion results upfront")
e27f928ee1cb ("io_uring: add io_uring_types.h")
4d4c9cff4f70 ("io_uring: define a request type cleanup handler")
890968dc0336 ("io_uring: unify struct io_symlink and io_hardlink")
9a3a11f977f9 ("io_uring: convert iouring_cmd to io_cmd_type")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From 72bd80252feeb3bef8724230ee15d9f7ab541c6e Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@xxxxxxxxx>
Date: Thu, 1 Feb 2024 06:42:36 -0700
Subject: [PATCH] io_uring/net: fix sr->len for IORING_OP_RECV with MSG_WAITALL
 and buffers

If we use IORING_OP_RECV with provided buffers and pass in '0' as the
length of the request, the length is retrieved from the selected buffer.
If MSG_WAITALL is also set and we get a short receive, then we may hit
the retry path which decrements sr->len and increments the buffer for
a retry. However, the length is still zero at this point, which means
that sr->len now becomes huge and import_ubuf() will cap it to
MAX_RW_COUNT and subsequently return -EFAULT for the range as a whole.

Fix this by always assigning sr->len once the buffer has been selected.

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 7ba89d2af17a ("io_uring: ensure recv and recvmsg handle MSG_WAITALL correctly")
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>

diff --git a/io_uring/net.c b/io_uring/net.c
index a12ff69e6843..43bc9a5f96f9 100644
--- a/io_uring/net.c
+++ b/io_uring/net.c
@@ -923,6 +923,7 @@ int io_recv(struct io_kiocb *req, unsigned int issue_flags)
 		if (!buf)
 			return -ENOBUFS;
 		sr->buf = buf;
+		sr->len = len;
 	}
 
 	ret = import_ubuf(ITER_DEST, sr->buf, len, &msg.msg_iter);