FAILED: patch "[PATCH] smb: client: fix file type corruption in" failed to apply to 5.15-stable tree

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 <[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-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x 65d5dbdc089be42fc48a6f77bc6b648307f34b17
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026091645-lip-thinness-9a03@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

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

From 65d5dbdc089be42fc48a6f77bc6b648307f34b17 Mon Sep 17 00:00:00 2001
From: Paulo Alcantara <[email protected]>
Date: Sun, 6 Sep 2026 16:01:16 -0300
Subject: [PATCH] smb: client: fix file type corruption in
posix_reparse_to_fattr()

Setting the file type in cf_mode without clearing the existing S_IFMT bits first is wrong as it corrupts the file type when cf_mode already has type bits set (e.g. S_IFREG | S_IFCHR == S_IFLNK).

Use a local ftype variable to collect the new file type and apply it after validation succeeds, clearing S_IFMT and setting the new type in a single assignment. This avoids stripping cf_mode on malformed reparse points where the function returns false early.

index 8a19dee564b8..616ca2dbfac4 100644
@@ -1212,6 +1212,7 @@ static bool posix_reparse_to_fattr(struct cifs_sb_info *cifs_sb,
 				   struct cifs_open_info_data *data)
 {
 	struct reparse_nfs_data_buffer *buf = (struct reparse_nfs_data_buffer *)data->reparse.buf;
+	umode_t ftype;
 
 	if (buf == NULL)
 		return true;

@@ -1227,7 +1228,7 @@ static bool posix_reparse_to_fattr(struct cifs_sb_info *cifs_sb,
 			WARN_ON_ONCE(1);
 			return false;
 		}
-		fattr->cf_mode |= S_IFCHR;
+		ftype = S_IFCHR;
 		fattr->cf_rdev = reparse_mkdev(buf->DataBuffer);
 		break;
 	case NFS_SPECFILE_BLK:

@@ -1235,22 +1236,23 @@ static bool posix_reparse_to_fattr(struct cifs_sb_info *cifs_sb,
 			WARN_ON_ONCE(1);
 			return false;
 		}
-		fattr->cf_mode |= S_IFBLK;
+		ftype = S_IFBLK;
 		fattr->cf_rdev = reparse_mkdev(buf->DataBuffer);
 		break;
 	case NFS_SPECFILE_FIFO:
-		fattr->cf_mode |= S_IFIFO;
+		ftype = S_IFIFO;
 		break;
 	case NFS_SPECFILE_SOCK:
-		fattr->cf_mode |= S_IFSOCK;
+		ftype = S_IFSOCK;
 		break;
 	case NFS_SPECFILE_LNK:
-		fattr->cf_mode |= S_IFLNK;
+		ftype = S_IFLNK;
 		break;
 	default:
 		WARN_ON_ONCE(1);
 		return false;
 	}
+	fattr->cf_mode = (fattr->cf_mode & ~S_IFMT) | ftype;
 	return true;
 }