linux-kernel - Re: [PATCH v2] smb: client: Fix refcount leak for cifs_sb

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Message-ID: <CAH2r5mtNVsFcMsW+=jdw4=hc4rssca-0fWMg4uhipBbuHnQ9GQ@mail.gmail.com>
Date: Wed, 15 Oct 2025 22:12:03 -0500
From: Steve French <smfrench@...il.com>
To: Shuhao Fu <sfual@....ust.hk>
Cc: Steve French <sfrench@...ba.org>, Markus Elfring <Markus.Elfring@....de>, linux-cifs@...r.kernel.org, 
	samba-technical@...ts.samba.org, Bharath SM <bharathsm@...rosoft.com>, 
	Paulo Alcantara <pc@...guebit.org>, Ronnie Sahlberg <ronniesahlberg@...il.com>, 
	Shyam Prasad N <sprasad@...rosoft.com>, Tom Talpey <tom@...pey.com>, 
	LKML <linux-kernel@...r.kernel.org>, kernel-janitors@...r.kernel.org
Subject: Re: [PATCH v2] smb: client: Fix refcount leak for cifs_sb_tlink

updated the patch in cifs-2.6.git for-next

On Wed, Oct 15, 2025 at 9:53 PM Shuhao Fu <sfual@....ust.hk> wrote:
>
> Fix three refcount inconsistency issues related to `cifs_sb_tlink`.
>
> Comments for `cifs_sb_tlink` state that `cifs_put_tlink()` needs to be
> called after successful calls to `cifs_sb_tlink()`. Three calls fail to
> update refcount accordingly, leading to possible resource leaks.
>
> Fixes: 8ceb98437946 ("CIFS: Move rename to ops struct")
> Fixes: 2f1afe25997f ("cifs: Use smb 2 - 3 and cifsacl mount options getacl functions")
> Fixes: 366ed846df60 ("cifs: Use smb 2 - 3 and cifsacl mount options setacl function")
> Signed-off-by: Shuhao Fu <sfual@....ust.hk>
> ---
> Change in v2:
> 1. improved patch wording
> 2. nicer goto label naming
>
> Link to v1: https://lore.kernel.org/linux-cifs/aOzRF9JB9VkBKapw@osx.local/
> ---
>  fs/smb/client/inode.c   | 6 ++++--
>  fs/smb/client/smb2ops.c | 8 ++++----
>  2 files changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/fs/smb/client/inode.c b/fs/smb/client/inode.c
> index 239dd84a3..098a79b7a 100644
> --- a/fs/smb/client/inode.c
> +++ b/fs/smb/client/inode.c
> @@ -2431,8 +2431,10 @@ cifs_do_rename(const unsigned int xid, struct dentry *from_dentry,
>         tcon = tlink_tcon(tlink);
>         server = tcon->ses->server;
>
> -       if (!server->ops->rename)
> -               return -ENOSYS;
> +       if (!server->ops->rename) {
> +               rc = -ENOSYS;
> +               goto do_rename_exit;
> +       }
>
>         /* try path-based rename first */
>         rc = server->ops->rename(xid, tcon, from_dentry,
> diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c
> index 7c392cf59..00b3f769e 100644
> --- a/fs/smb/client/smb2ops.c
> +++ b/fs/smb/client/smb2ops.c
> @@ -3212,8 +3212,7 @@ get_smb2_acl_by_path(struct cifs_sb_info *cifs_sb,
>         utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
>         if (!utf16_path) {
>                 rc = -ENOMEM;
> -               free_xid(xid);
> -               return ERR_PTR(rc);
> +               goto put_tlink;
>         }
>
>         oparms = (struct cifs_open_parms) {
> @@ -3245,6 +3244,7 @@ get_smb2_acl_by_path(struct cifs_sb_info *cifs_sb,
>                 SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
>         }
>
> +put_tlink:
>         cifs_put_tlink(tlink);
>         free_xid(xid);
>
> @@ -3285,8 +3285,7 @@ set_smb2_acl(struct smb_ntsd *pnntsd, __u32 acllen,
>         utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
>         if (!utf16_path) {
>                 rc = -ENOMEM;
> -               free_xid(xid);
> -               return rc;
> +               goto put_tlink;
>         }
>
>         oparms = (struct cifs_open_parms) {
> @@ -3307,6 +3306,7 @@ set_smb2_acl(struct smb_ntsd *pnntsd, __u32 acllen,
>                 SMB2_close(xid, tcon, fid.persistent_fid, fid.volatile_fid);
>         }
>
> +put_tlink:
>         cifs_put_tlink(tlink);
>         free_xid(xid);
>         return rc;
> --
> 2.39.5 (Apple Git-154)
>
>


-- 
Thanks,

Steve