FAILED: patch "[PATCH] lockd: fix NULL dereference on lockowner allocation failure" failed to apply to 6.1-stable tree

FAILED: patch "[PATCH] lockd: fix NULL dereference on lockowner allocation failure" failed to apply to 6.1-stable tree

[gregkh]

The patch below does not apply to the 6.1-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-6.1.y
git checkout FETCH_HEAD
git cherry-pick -x 4c7fc129db061c7daab841c4f3c342d894832362
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026090351-duplex-next-aca8@gregkh' --subject-prefix 'PATCH 6.1.y' 'HEAD^..'

Possible dependencies:



thanks,

greg k-h

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

From 4c7fc129db061c7daab841c4f3c342d894832362 Mon Sep 17 00:00:00 2001
From: Shuangpeng Bai <shuangpeng.kernel@gmail.com>
Date: Fri, 17 Jul 2026 13:28:09 -0400
Subject: [PATCH] lockd: fix NULL dereference on lockowner allocation failure

nlmclnt_locks_init_private() installs NLM file lock operations even when
nlmclnt_find_lockowner() fails to allocate a lockowner. nlmclnt_proc()
then returns -ENOMEM, but the VFS still tears down the partially
initialized file_lock and calls locks_release_private().

That invokes nlmclnt_locks_release_private(), which dereferences
fl->fl_u.nfs_fl.owner and crashes because the owner was never installed.

Clear fl_ops before attempting to initialize the NLM private state, and
install the NLM lock operations only after a lockowner has been allocated
successfully.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Shuangpeng Bai <shuangpeng.kernel@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

diff --git a/fs/lockd/clntproc.c b/fs/lockd/clntproc.c
index f06faf577cea..f8018bfe9c64 100644
--- a/fs/lockd/clntproc.c
+++ b/fs/lockd/clntproc.c
@@ -487,9 +487,12 @@ static const struct file_lock_operations nlmclnt_lock_ops = {
 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
 {
 	fl->fl_u.nfs_fl.state = 0;
+	fl->fl_ops = NULL;
 	fl->fl_u.nfs_fl.owner = nlmclnt_find_lockowner(host,
 						       fl->c.flc_owner);
 	INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
+	if (!fl->fl_u.nfs_fl.owner)
+		return;
 	fl->fl_ops = &nlmclnt_lock_ops;
 }
 

[PATCH 6.1.y 1/2] filelock: split common fields into struct file_lock_core

[Sasha Levin]

From: Jeff Layton <jlayton@kernel.org>

[ Upstream commit a69ce85ec9af6bdc0b3511959a7dc1a324e5e16a ]

In a future patch, we're going to split file leases into their own
structure. Since a lot of the underlying machinery uses the same fields
move those into a new file_lock_core, and embed that inside struct
file_lock.

For now, add some macros to ensure that we can continue to build while
the conversion is in progress.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://lore.kernel.org/r/20240131-flsplit-v3-17-c6129007ee8d@kernel.org
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Christian Brauner <brauner@kernel.org>

[6.1 dependency adaptation]
The stable tree still defines struct file_lock in include/linux/fs.h and
has neither the separate filelock.h header nor the later locking helpers.
Define file_lock_core in the existing header, retaining the stable tree's
unsigned fl_pid type. Embed the core in an anonymous union with matching
legacy fields so existing users and trace-event field names continue to
work without global field-name macros or a tree-wide conversion.

Use c.flc_owner in nlmclnt_locks_init_private(), with upstream formatting,
to prepare the exact context required by 4c7fc129db061 ("lockd: fix NULL
dereference on lockowner allocation failure"). Leave that fix itself to
the target commit. Drop the unused macro-enabling includes, conversions
of absent helpers, and unrelated whitespace changes. No functions are
added.

[ sashal: Reduced backport -- upstream a69ce85ec9af6 touches 24 file(s), this
  backport carries 2. Not backported here:
  fs/9p/vfs_file.c
  fs/afs/internal.h
  fs/ceph/locks.c
  fs/dlm/plock.c
  fs/fuse/file.c
  fs/gfs2/file.c
  fs/locks.c
  fs/nfsd/netns.h
  ... and 15 more
  This note is generated from the file lists only; see the resolution record
  for the reasoning. ]

Stable-dep-of: 4c7fc129db06 ("lockd: fix NULL dereference on lockowner allocation failure")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/lockd/clntproc.c |  3 ++-
 include/linux/fs.h  | 56 ++++++++++++++++++++++++++++++++-------------
 2 files changed, 42 insertions(+), 17 deletions(-)

diff --git a/fs/lockd/clntproc.c b/fs/lockd/clntproc.c
index 99fffc9cb9585..32790a57351a5 100644
--- a/fs/lockd/clntproc.c
+++ b/fs/lockd/clntproc.c
@@ -479,7 +479,8 @@ static const struct file_lock_operations nlmclnt_lock_ops = {
 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
 {
 	fl->fl_u.nfs_fl.state = 0;
-	fl->fl_u.nfs_fl.owner = nlmclnt_find_lockowner(host, fl->fl_owner);
+	fl->fl_u.nfs_fl.owner = nlmclnt_find_lockowner(host,
+						       fl->c.flc_owner);
 	INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
 	fl->fl_ops = &nlmclnt_lock_ops;
 }
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 264381ae06e26..40086076e6051 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1075,6 +1075,25 @@ bool opens_in_grace(struct net *);
 /* that will die - we need it for nfs_lock_info */
 #include <linux/nfs_fs_i.h>
 
+struct file_lock_core {
+	struct file_lock *flc_blocker;	/* The lock that is blocking us */
+	struct list_head flc_list;	/* link into file_lock_context */
+	struct hlist_node flc_link;	/* node in global lists */
+	struct list_head flc_blocked_requests;	/* list of requests with
+						 * ->fl_blocker pointing here
+						 */
+	struct list_head flc_blocked_member;	/* node in
+						 * ->fl_blocker->fl_blocked_requests
+						 */
+	fl_owner_t flc_owner;
+	unsigned int flc_flags;
+	unsigned char flc_type;
+	unsigned int flc_pid;
+	int flc_link_cpu;		/* what cpu's list is this on? */
+	wait_queue_head_t flc_wait;
+	struct file *flc_file;
+};
+
 /*
  * struct file_lock represents a generic "file lock". It's used to represent
  * POSIX byte range locks, BSD (flock) locks, and leases. It's important to
@@ -1093,22 +1112,27 @@ bool opens_in_grace(struct net *);
  * Obviously, the last two criteria only matter for POSIX locks.
  */
 struct file_lock {
-	struct file_lock *fl_blocker;	/* The lock, that is blocking us */
-	struct list_head fl_list;	/* link into file_lock_context */
-	struct hlist_node fl_link;	/* node in global lists */
-	struct list_head fl_blocked_requests;	/* list of requests with
-						 * ->fl_blocker pointing here
-						 */
-	struct list_head fl_blocked_member;	/* node in
-						 * ->fl_blocker->fl_blocked_requests
-						 */
-	fl_owner_t fl_owner;
-	unsigned int fl_flags;
-	unsigned char fl_type;
-	unsigned int fl_pid;
-	int fl_link_cpu;		/* what cpu's list is this on? */
-	wait_queue_head_t fl_wait;
-	struct file *fl_file;
+	union {
+		struct file_lock_core c;
+		/*
+		 * Legacy aliases for the common core. Keep this layout in sync
+		 * with struct file_lock_core.
+		 */
+		struct {
+			struct file_lock *fl_blocker;
+			struct list_head fl_list;
+			struct hlist_node fl_link;
+			struct list_head fl_blocked_requests;
+			struct list_head fl_blocked_member;
+			fl_owner_t fl_owner;
+			unsigned int fl_flags;
+			unsigned char fl_type;
+			unsigned int fl_pid;
+			int fl_link_cpu;
+			wait_queue_head_t fl_wait;
+			struct file *fl_file;
+		};
+	};
 	loff_t fl_start;
 	loff_t fl_end;
 
-- 
2.53.0

[PATCH 6.1.y 2/2] lockd: fix NULL dereference on lockowner allocation failure

[Sasha Levin]

From: Shuangpeng Bai <shuangpeng.kernel@gmail.com>

[ Upstream commit 4c7fc129db061c7daab841c4f3c342d894832362 ]

nlmclnt_locks_init_private() installs NLM file lock operations even when
nlmclnt_find_lockowner() fails to allocate a lockowner. nlmclnt_proc()
then returns -ENOMEM, but the VFS still tears down the partially
initialized file_lock and calls locks_release_private().

That invokes nlmclnt_locks_release_private(), which dereferences
fl->fl_u.nfs_fl.owner and crashes because the owner was never installed.

Clear fl_ops before attempting to initialize the NLM private state, and
install the NLM lock operations only after a lockowner has been allocated
successfully.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Signed-off-by: Shuangpeng Bai <shuangpeng.kernel@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/lockd/clntproc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/lockd/clntproc.c b/fs/lockd/clntproc.c
index 32790a57351a5..bae25519771d1 100644
--- a/fs/lockd/clntproc.c
+++ b/fs/lockd/clntproc.c
@@ -479,9 +479,12 @@ static const struct file_lock_operations nlmclnt_lock_ops = {
 static void nlmclnt_locks_init_private(struct file_lock *fl, struct nlm_host *host)
 {
 	fl->fl_u.nfs_fl.state = 0;
+	fl->fl_ops = NULL;
 	fl->fl_u.nfs_fl.owner = nlmclnt_find_lockowner(host,
 						       fl->c.flc_owner);
 	INIT_LIST_HEAD(&fl->fl_u.nfs_fl.list);
+	if (!fl->fl_u.nfs_fl.owner)
+		return;
 	fl->fl_ops = &nlmclnt_lock_ops;
 }
 
-- 
2.53.0