FAILED: patch "[PATCH] smb3: missing lock when picking channel" failed to apply to 4.19-stable tree

FAILED: patch "[PATCH] smb3: missing lock when picking channel" failed to apply to 4.19-stable tree

[gregkh]

The patch below does not apply to the 4.19-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@vger.kernel.org>.

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-4.19.y
git checkout FETCH_HEAD
git cherry-pick -x 8094a600245e9b28eb36a13036f202ad67c1f887
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2024042917-regulate-exquisite-3f14@gregkh' --subject-prefix 'PATCH 4.19.y' HEAD^..

Possible dependencies:

8094a600245e ("smb3: missing lock when picking channel")
38c8a9a52082 ("smb: move client and server files to common directory fs/smb")
ea90708d3cf3 ("cifs: use the least loaded channel for sending requests")
abdb1742a312 ("cifs: get rid of mount options string parsing")
9fd29a5bae6e ("cifs: use fs_context for automounts")
5dd8ce24667a ("cifs: missing directory in MAINTAINERS file")
332019e23a51 ("Merge tag '5.20-rc-smb3-client-fixes-part2' of git://git.samba.org/sfrench/cifs-2.6")

thanks,

greg k-h

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

From 8094a600245e9b28eb36a13036f202ad67c1f887 Mon Sep 17 00:00:00 2001
From: Steve French <stfrench@microsoft.com>
Date: Thu, 25 Apr 2024 11:30:16 -0500
Subject: [PATCH] smb3: missing lock when picking channel

Coverity spotted a place where we should have been holding the
channel lock when accessing the ses channel index.

Addresses-Coverity: 1582039 ("Data race condition (MISSING_LOCK)")
Cc: stable@vger.kernel.org
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/smb/client/transport.c b/fs/smb/client/transport.c
index 994d70193432..e1a79e031b28 100644
--- a/fs/smb/client/transport.c
+++ b/fs/smb/client/transport.c
@@ -1057,9 +1057,11 @@ struct TCP_Server_Info *cifs_pick_channel(struct cifs_ses *ses)
 		index = (uint)atomic_inc_return(&ses->chan_seq);
 		index %= ses->chan_count;
 	}
+
+	server = ses->chans[index].server;
 	spin_unlock(&ses->chan_lock);
 
-	return ses->chans[index].server;
+	return server;
 }
 
 int