FAILED: patch "[PATCH] ksmbd: fix race condition from parallel smb2 logoff requests" 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 7ca9da7d873ee8024e9548d3366101c2b6843eab
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2023100849-celibacy-urchin-788f@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^..

Possible dependencies:

7ca9da7d873e ("ksmbd: fix race condition from parallel smb2 logoff requests")
e2b76ab8b5c9 ("ksmbd: add support for read compound")
e202a1e8634b ("ksmbd: no response from compound read")
7b7d709ef7cf ("ksmbd: add missing compound request handing in some commands")
81a94b27847f ("ksmbd: use kvzalloc instead of kvmalloc")
38c8a9a52082 ("smb: move client and server files to common directory fs/smb")
30210947a343 ("ksmbd: fix racy issue under cocurrent smb2 tree disconnect")
abcc506a9a71 ("ksmbd: fix racy issue from smb2 close and logoff with multichannel")
ea174a918939 ("ksmbd: destroy expired sessions")
f5c779b7ddbd ("ksmbd: fix racy issue from session setup and logoff")
74d7970febf7 ("ksmbd: fix racy issue from using ->d_parent and ->d_name")
34e8ccf9ce24 ("ksmbd: set NegotiateContextCount once instead of every inc")
42bc6793e452 ("Merge tag 'pull-lock_rename_child' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs into ksmbd-for-next")

thanks,

greg k-h

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

>From 7ca9da7d873ee8024e9548d3366101c2b6843eab Mon Sep 17 00:00:00 2001
From: Namjae Jeon <linkinjeon@xxxxxxxxxx>
Date: Wed, 4 Oct 2023 18:30:14 +0900
Subject: [PATCH] ksmbd: fix race condition from parallel smb2 logoff requests

If parallel smb2 logoff requests come in before closing door, running
request count becomes more than 1 even though connection status is set to
KSMBD_SESS_NEED_RECONNECT. It can't get condition true, and sleep forever.
This patch fix race condition problem by returning error if connection
status was already set to KSMBD_SESS_NEED_RECONNECT.

Reported-by: luosili <rootlab@xxxxxxxxxx>
Signed-off-by: Namjae Jeon <linkinjeon@xxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>

diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c
index b9d6e8e451ba..e774c9855f7f 100644
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -2164,17 +2164,17 @@ int smb2_session_logoff(struct ksmbd_work *work)
 
 	ksmbd_debug(SMB, "request\n");
 
-	sess_id = le64_to_cpu(req->hdr.SessionId);
-
-	rsp->StructureSize = cpu_to_le16(4);
-	err = ksmbd_iov_pin_rsp(work, rsp, sizeof(struct smb2_logoff_rsp));
-	if (err) {
-		rsp->hdr.Status = STATUS_INSUFFICIENT_RESOURCES;
+	ksmbd_conn_lock(conn);
+	if (!ksmbd_conn_good(conn)) {
+		ksmbd_conn_unlock(conn);
+		rsp->hdr.Status = STATUS_NETWORK_NAME_DELETED;
 		smb2_set_err_rsp(work);
-		return err;
+		return -ENOENT;
 	}
-
+	sess_id = le64_to_cpu(req->hdr.SessionId);
 	ksmbd_all_conn_set_status(sess_id, KSMBD_SESS_NEED_RECONNECT);
+	ksmbd_conn_unlock(conn);
+
 	ksmbd_close_session_fds(work);
 	ksmbd_conn_wait_idle(conn, sess_id);
 
@@ -2196,6 +2196,14 @@ int smb2_session_logoff(struct ksmbd_work *work)
 	ksmbd_free_user(sess->user);
 	sess->user = NULL;
 	ksmbd_all_conn_set_status(sess_id, KSMBD_SESS_NEED_NEGOTIATE);
+
+	rsp->StructureSize = cpu_to_le16(4);
+	err = ksmbd_iov_pin_rsp(work, rsp, sizeof(struct smb2_logoff_rsp));
+	if (err) {
+		rsp->hdr.Status = STATUS_INSUFFICIENT_RESOURCES;
+		smb2_set_err_rsp(work);
+		return err;
+	}
 	return 0;
 }