The patch below does not apply to the 5.10-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-5.10.y git checkout FETCH_HEAD git cherry-pick -x 3184b6a5a24ec9ee74087b2a550476f386df7dc2 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025120144-dismiss-quilt-863b@gregkh' --subject-prefix 'PATCH 5.10.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

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

From 3184b6a5a24ec9ee74087b2a550476f386df7dc2 Mon Sep 17 00:00:00 2001 From: Paulo Alcantara pc@manguebit.org Date: Mon, 24 Nov 2025 17:00:36 -0300 Subject: [PATCH] smb: client: fix memory leak in cifs_construct_tcon()

When having a multiuser mount with domain= specified and using cifscreds, cifs_set_cifscreds() will end up setting @ctx->domainname, so it needs to be freed before leaving cifs_construct_tcon().

This fixes the following memory leak reported by kmemleak:

mount.cifs //srv/share /mnt -o domain=ZELDA,multiuser,... su - testuser cifscreds add -d ZELDA -u testuser ... ls /mnt/1 ... umount /mnt echo scan > /sys/kernel/debug/kmemleak cat /sys/kernel/debug/kmemleak unreferenced object 0xffff8881203c3f08 (size 8): comm "ls", pid 5060, jiffies 4307222943 hex dump (first 8 bytes): 5a 45 4c 44 41 00 cc cc ZELDA... backtrace (crc d109a8cf): __kmalloc_node_track_caller_noprof+0x572/0x710 kstrdup+0x3a/0x70 cifs_sb_tlink+0x1209/0x1770 [cifs] cifs_get_fattr+0xe1/0xf50 [cifs] cifs_get_inode_info+0xb5/0x240 [cifs] cifs_revalidate_dentry_attr+0x2d1/0x470 [cifs] cifs_getattr+0x28e/0x450 [cifs] vfs_getattr_nosec+0x126/0x180 vfs_statx+0xf6/0x220 do_statx+0xab/0x110 __x64_sys_statx+0xd5/0x130 do_syscall_64+0xbb/0x380 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Fixes: f2aee329a68f ("cifs: set domainName when a domain-key is used in multiuser") Signed-off-by: Paulo Alcantara (Red Hat) pc@manguebit.org Reviewed-by: David Howells dhowells@redhat.com Cc: Jay Shin jaeshin@redhat.com Cc: stable@vger.kernel.org Cc: linux-cifs@vger.kernel.org Signed-off-by: Steve French stfrench@microsoft.com

diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c index 55cb4b0cbd48..2f94d93b95e9 100644 --- a/fs/smb/client/connect.c +++ b/fs/smb/client/connect.c @@ -4451,6 +4451,7 @@ cifs_construct_tcon(struct cifs_sb_info *cifs_sb, kuid_t fsuid)

out: kfree(ctx->username); + kfree(ctx->domainname); kfree_sensitive(ctx->password); kfree(origin_fullpath); kfree(ctx);