Re: [PATCH] fuse: fix race conditions on fi->nlookup

[Bernd Schubert]

On 8/10/24 05:42, yangyun wrote:
> Lock on fi->nlookup is missed in fuse_fill_super_submount(). Add lock
> on it to prevent race conditions.
> 
> Fixes: 1866d779d5d2 ("fuse: Allow fuse_fill_super_common() for submounts")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: yangyun <yangyun50@xxxxxxxxxx>
> ---
>  fs/fuse/inode.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
> index 99e44ea7d875..2e220f245ceb 100644
> --- a/fs/fuse/inode.c
> +++ b/fs/fuse/inode.c
> @@ -1593,7 +1593,9 @@ static int fuse_fill_super_submount(struct super_block *sb,
>  	 * that, though, so undo it here.
>  	 */
>  	fi = get_fuse_inode(root);
> +	spin_lock(&fi->lock);
>  	fi->nlookup--;
> +	spin_unlock(&fi->lock);
>  
>  	sb->s_d_op = &fuse_dentry_operations;
>  	sb->s_root = d_make_root(root);

LGTM


Reviewed-by: Bernd Schubert <bschubert@xxxxxxx>