FAILED: patch "[PATCH] smb: client: fix WSL reparse point uid/gid override" failed to apply to 6.6-stable tree

PATCH New [email protected] 2 participants 4 messages Sep 16 – Sep 17

Subsystems (4)

Stable branch VFS SMB client (CIFS) Kernel SMB3 server (ksmbd)

lore

Share & tools

lore

[email protected]

author maintainer

2026-09-16 16:52 UTC #0 lore raw

The patch below does not apply to the 6.6-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 <[email protected]>.

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-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x cd2b2b57921d4caa7875e83198bb2aa71254328b
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026091653-repaying-rockslide-b109@gregkh' --subject-prefix 'PATCH 6.6.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

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

From cd2b2b57921d4caa7875e83198bb2aa71254328b Mon Sep 17 00:00:00 2001
From: Paulo Alcantara <[email protected]>
Date: Sun, 6 Sep 2026 14:40:23 -0300
Subject: [PATCH] smb: client: fix WSL reparse point uid/gid override

wsl_to_fattr() unconditionally overwrites cf_uid/cf_gid with values from WSL extended attributes ($LXUID/$LXGID), ignoring the forceuid and forcegid mount options.

Fix this by initializing cf_uid/cf_gid to the mount defaults and gating the $LXUID/$LXGID EA parsing on forceuid/forcegid.

Closes https://sashiko.dev/#/patchset/20260906190803.667489-1-pc%40manguebit.org

Reviewed-by Namjae Jeon <[email protected]>

Signed-off-by Paulo Alcantara <[email protected]>

Cc Ronnie Sahlberg <[email protected]>

Cc Shyam Prasad N <[email protected]>

Cc Tom Talpey <[email protected]>

Cc Bharath SM <[email protected]>

Cc [email protected]

fs/smb/client/reparse.c +11 -5

index 5cc5b0410d48..178da801e775 100644
@@ -1137,10 +1137,14 @@ static bool wsl_to_fattr(struct cifs_open_info_data *data,
 			 struct cifs_sb_info *cifs_sb,
 			 u32 tag, struct cifs_fattr *fattr)
 {
+	unsigned int sbflags = cifs_sb_flags(cifs_sb);
 	struct smb2_file_full_ea_info *ea;
 	bool have_xattr_dev = false;
 	u32 next = 0;
 
+	fattr->cf_uid = cifs_sb->ctx->linux_uid;
+	fattr->cf_gid = cifs_sb->ctx->linux_gid;
+
 	switch (tag) {
 	case IO_REPARSE_TAG_LX_SYMLINK:
 		fattr->cf_mode |= S_IFLNK;

@@ -1177,11 +1181,13 @@ static bool wsl_to_fattr(struct cifs_open_info_data *data,
 		nlen = ea->ea_name_length;
 		v = (void *)((u8 *)ea->ea_data + ea->ea_name_length + 1);
 
-		if (!strncmp(name, SMB2_WSL_XATTR_UID, nlen))
-			fattr->cf_uid = wsl_make_kuid(cifs_sb, v);
-		else if (!strncmp(name, SMB2_WSL_XATTR_GID, nlen))
-			fattr->cf_gid = wsl_make_kgid(cifs_sb, v);
-		else if (!strncmp(name, SMB2_WSL_XATTR_MODE, nlen)) {
+		if (!strncmp(name, SMB2_WSL_XATTR_UID, nlen)) {
+			if (!(sbflags & CIFS_MOUNT_OVERR_UID))
+				fattr->cf_uid = wsl_make_kuid(cifs_sb, v);
+		} else if (!strncmp(name, SMB2_WSL_XATTR_GID, nlen)) {
+			if (!(sbflags & CIFS_MOUNT_OVERR_GID))
+				fattr->cf_gid = wsl_make_kgid(cifs_sb, v);
+		} else if (!strncmp(name, SMB2_WSL_XATTR_MODE, nlen)) {
 			/* File type in reparse point tag and in xattr mode must match. */
 			if (S_DT(fattr->cf_mode) != S_DT(le32_to_cpu(*(__le32 *)v)))
 				return false;

Sasha Levin

maintainer

2026-09-17 14:02 UTC #1 lore raw

PATCH 1/3 cifs: Scripted clean up fs/smb/client/fscache.h

From: David Howells <[email protected]>

[ Upstream commit bc3de356aae666de5d8b5131545be87cf7754431 ]

Remove externs, correct argument names and reformat declarations.

Signed-off-by David Howells <[email protected]>

cc Steve French <[email protected]>

cc Paulo Alcantara <[email protected]>

cc Enzo Matsumiya <[email protected]>

cc [email protected]

Acked-by Enzo Matsumiya <[email protected]>

Signed-off-by Steve French <[email protected]>

Stable-dep-of: cd2b2b57921d ("smb: client: fix WSL reparse point uid/gid override")

Signed-off-by Sasha Levin <[email protected]>

---
 fs/smb/client/fscache.h | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

fs/smb/client/fscache.h +5 -5

index 1f2ea9f5cc9a8..4c2e269a268ed 100644
@@ -38,12 +38,12 @@ struct cifs_fscache_inode_coherency_data {
 /*
  * fscache.c
  */
-extern int cifs_fscache_get_super_cookie(struct cifs_tcon *);
-extern void cifs_fscache_release_super_cookie(struct cifs_tcon *);
+int cifs_fscache_get_super_cookie(struct cifs_tcon *tcon);
+void cifs_fscache_release_super_cookie(struct cifs_tcon *tcon);
 
-extern void cifs_fscache_get_inode_cookie(struct inode *inode);
-extern void cifs_fscache_release_inode_cookie(struct inode *);
-extern void cifs_fscache_unuse_inode_cookie(struct inode *inode, bool update);
+void cifs_fscache_get_inode_cookie(struct inode *inode);
+void cifs_fscache_release_inode_cookie(struct inode *inode);
+void cifs_fscache_unuse_inode_cookie(struct inode *inode, bool update);
 
 static inline
 void cifs_fscache_fill_coherency(struct inode *inode,

Signature · 1 line

2.53.0

Sasha Levin

maintainer

2026-09-17 14:02 UTC #2 lore raw

PATCH 2/3 smb: client: use atomic_t for mnt_cifs_flags

From: Paulo Alcantara <[email protected]>

[ Upstream commit 4fc3a433c13944ee5766ec5b9bf6f1eb4d29b880 ]

Use atomic_t for cifs_sb_info::mnt_cifs_flags as it's currently accessed locklessly and may be changed concurrently in mount/remount and reconnect paths.

Signed-off-by Paulo Alcantara (Red Hat) <[email protected]>

Reviewed-by David Howells <[email protected]>

Cc [email protected]

Signed-off-by Steve French <[email protected]>

[ Stable dependency adaptation for cd2b2b57921d:
The 6.6 WSL parser already matches the target's preimage. Keep only the cifs_sb_flags interface needed by that fix and its WSL uid/gid callers. Implement the accessor as a READ_ONCE macro over the existing unsigned mount flags, without adding functions. Drop the atomic_t conversion, generic CIFS_SB accessors and unrelated client-wide refactoring, which depend on newer SMB code absent from this tree. This is preparation for the WSL ownership fix, not a backport of the full flag-writer race fix. ]

[ sashal: Reduced backport -- upstream 4fc3a433c1394 touches 27 file(s), this
backport carries 2. Not backported here:
fs/smb/client/cached_dir.c
fs/smb/client/cifsacl.c
fs/smb/client/cifsfs.c
fs/smb/client/cifs_fs_sb.h
fs/smb/client/cifs_ioctl.h
fs/smb/client/cifs_unicode.c
fs/smb/client/cifs_unicode.h
fs/smb/client/connect.c
... and 17 more
This note is generated from the file lists only; see the resolution record for the reasoning. ]

Stable-dep-of: cd2b2b57921d ("smb: client: fix WSL reparse point uid/gid override")

Signed-off-by Sasha Levin <[email protected]>

---
 fs/smb/client/cifsglob.h | 3 +++
 fs/smb/client/reparse.h  | 4 ++--
 2 files changed, 5 insertions(+), 2 deletions(-)

fs/smb/client/cifsglob.h +3 -0

index a4e0618c58efc..61ebd6d8eb41e 100644
@@ -1603,6 +1603,9 @@ CIFS_FILE_SB(struct file *file)
 	return CIFS_SB(file_inode(file)->i_sb);
 }
 
+/* Read mount flags once for paths that need a consistent snapshot. */
+#define cifs_sb_flags(cifs_sb) READ_ONCE((cifs_sb)->mnt_cifs_flags)
+
 static inline char CIFS_DIR_SEP(const struct cifs_sb_info *cifs_sb)
 {
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_POSIX_PATHS)

fs/smb/client/reparse.h +2 -2

index ff05b0e75c928..c15e4541cca06 100644
@@ -32,7 +32,7 @@ static inline kuid_t wsl_make_kuid(struct cifs_sb_info *cifs_sb,
 {
 	u32 uid = le32_to_cpu(*(__le32 *)ptr);
 
-	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_OVERR_UID)
+	if (cifs_sb_flags(cifs_sb) & CIFS_MOUNT_OVERR_UID)
 		return cifs_sb->ctx->linux_uid;
 	return make_kuid(current_user_ns(), uid);
 }

@@ -42,7 +42,7 @@ static inline kgid_t wsl_make_kgid(struct cifs_sb_info *cifs_sb,
 {
 	u32 gid = le32_to_cpu(*(__le32 *)ptr);
 
-	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_OVERR_GID)
+	if (cifs_sb_flags(cifs_sb) & CIFS_MOUNT_OVERR_GID)
 		return cifs_sb->ctx->linux_gid;
 	return make_kgid(current_user_ns(), gid);
 }

Signature · 1 line

2.53.0

Sasha Levin

maintainer

2026-09-17 14:02 UTC #3 lore raw

PATCH 3/3 smb: client: fix WSL reparse point uid/gid override

In reply to Sasha Levin

From: Paulo Alcantara <[email protected]>

[ Upstream commit cd2b2b57921d4caa7875e83198bb2aa71254328b ]

wsl_to_fattr() unconditionally overwrites cf_uid/cf_gid with values from WSL extended attributes ($LXUID/$LXGID), ignoring the forceuid and forcegid mount options.

Fix this by initializing cf_uid/cf_gid to the mount defaults and gating the $LXUID/$LXGID EA parsing on forceuid/forcegid.

Closes https://sashiko.dev/#/patchset/20260906190803.667489-1-pc%40manguebit.org

Reviewed-by Namjae Jeon <[email protected]>

Signed-off-by Paulo Alcantara <[email protected]>

Cc Ronnie Sahlberg <[email protected]>

Cc Shyam Prasad N <[email protected]>

Cc Tom Talpey <[email protected]>

Cc Bharath SM <[email protected]>

Cc [email protected]

Signed-off-by Sasha Levin <[email protected]>

---
 fs/smb/client/reparse.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

fs/smb/client/reparse.c +11 -5

index 4d45c31336df1..fd406f77053fb 100644
@@ -678,10 +678,14 @@ static bool wsl_to_fattr(struct cifs_open_info_data *data,
 			 struct cifs_sb_info *cifs_sb,
 			 u32 tag, struct cifs_fattr *fattr)
 {
+	unsigned int sbflags = cifs_sb_flags(cifs_sb);
 	struct smb2_file_full_ea_info *ea;
 	bool have_xattr_dev = false;
 	u32 next = 0;
 
+	fattr->cf_uid = cifs_sb->ctx->linux_uid;
+	fattr->cf_gid = cifs_sb->ctx->linux_gid;
+
 	switch (tag) {
 	case IO_REPARSE_TAG_LX_SYMLINK:
 		fattr->cf_mode |= S_IFLNK;

@@ -718,11 +722,13 @@ static bool wsl_to_fattr(struct cifs_open_info_data *data,
 		nlen = ea->ea_name_length;
 		v = (void *)((u8 *)ea->ea_data + ea->ea_name_length + 1);
 
-		if (!strncmp(name, SMB2_WSL_XATTR_UID, nlen))
-			fattr->cf_uid = wsl_make_kuid(cifs_sb, v);
-		else if (!strncmp(name, SMB2_WSL_XATTR_GID, nlen))
-			fattr->cf_gid = wsl_make_kgid(cifs_sb, v);
-		else if (!strncmp(name, SMB2_WSL_XATTR_MODE, nlen)) {
+		if (!strncmp(name, SMB2_WSL_XATTR_UID, nlen)) {
+			if (!(sbflags & CIFS_MOUNT_OVERR_UID))
+				fattr->cf_uid = wsl_make_kuid(cifs_sb, v);
+		} else if (!strncmp(name, SMB2_WSL_XATTR_GID, nlen)) {
+			if (!(sbflags & CIFS_MOUNT_OVERR_GID))
+				fattr->cf_gid = wsl_make_kgid(cifs_sb, v);
+		} else if (!strncmp(name, SMB2_WSL_XATTR_MODE, nlen)) {
 			/* File type in reparse point tag and in xattr mode must match. */
 			if (S_DT(fattr->cf_mode) != S_DT(le32_to_cpu(*(__le32 *)v)))
 				return false;

Signature · 1 line

2.53.0