Re: [syzbot] [mm?] [exfat?] [f2fs?] memory leak in __kfree_rcu_sheaf

David Timber
2026-05-03T07:41:14Z

On 5/3/26 16:27, syzbot wrote:
> Hello,
>
> syzbot has tested the proposed patch and the reproducer did not trigger any issue:
>
> Reported-by: syzbot+cae7809e9dc1459e4e63@syzkaller.appspotmail.com
> Tested-by: syzbot+cae7809e9dc1459e4e63@syzkaller.appspotmail.com
>
> Tested on:
>
> commit: 66edb901 Merge tag 'v7.1-p3' of git://git.kernel.org/p..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=11fb7082580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=9645c21cfd1d3e8f
> dashboard link: https://syzkaller.appspot.com/bug?extid=cae7809e9dc1459e4e63
> compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
> patch: https://syzkaller.appspot.com/x/patch.diff?x=17f2f326580000
>
> Note: testing is done by a robot and is best-effort only.

The error message might be misleading.

1. the report is done after f2fs attempted to mount the corrupt image,
not before
2. f2fs exhibits undefined behaviour, evident from the fs attempting to
do I/O out of blockdev bounds

This might have been cause by f2fs corrupting memory in which case the
leak report is invalid.

Davo