linux-kernel - Re: [PATCH] fs/super: fix memory leak of s_fs_info on setup_bdev

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Message-ID: <20251114-raubt-benoten-bf2d8f2317b2@brauner>
Date: Fri, 14 Nov 2025 12:55:30 +0100
From: Christian Brauner <brauner@...nel.org>
To: Mehdi Ben Hadj Khelifa <mehdi.benhadjkhelifa@...il.com>
Cc: syzbot+ad45f827c88778ff7df6@...kaller.appspotmail.com, 
	frank.li@...o.com, glaubitz@...sik.fu-berlin.de, linux-fsdevel@...r.kernel.org, 
	linux-kernel@...r.kernel.org, slava@...eyko.com, syzkaller-bugs@...glegroups.com
Subject: Re: [PATCH] fs/super: fix memory leak of s_fs_info on
 setup_bdev_super failure

On Fri, Nov 14, 2025 at 06:12:12AM +0100, Mehdi Ben Hadj Khelifa wrote:
> #syz test
> 
> diff --git a/fs/super.c b/fs/super.c
> index 5bab94fb7e03..a99e5281b057 100644
> --- a/fs/super.c
> +++ b/fs/super.c
> @@ -1690,6 +1690,11 @@ int get_tree_bdev_flags(struct fs_context *fc,
>  		if (!error)
>  			error = fill_super(s, fc);
>  		if (error) {
> +			/*
> +			 * return back sb_info ownership to fc to be freed by put_fs_context()
> +			 */
> +			fc->s_fs_info = s->s_fs_info;
> +			s->s_fs_info = NULL;
>  			deactivate_locked_super(s);
>  			return error;
>  		}
> -- 
> 2.51.2
> 

No, either free it in hfs_fill_super() when it fails or add a wrapper
around kill_block_super() for hfs and free it after ->kill_sb() has run.