Re: BUG: Mount ignores mount options

From: Tetsuo Handa
Date: Fri Aug 10 2018 - 11:13:31 EST

On 2018/08/10 23:05, Eric W. Biederman wrote:
> There is a serious problem with mount options today that fsopen does not
> address. The problem is that mount options are ignored for block based
> filesystems, and any other type of filesystem that follows the same
> pattern.
> The script below demonstrates this bug. Showing this bug can cause the
> ext4 "acl" "quota" and "user_xattr" options to be silently ignored.
> fsopen has my nack until it addresses this issue.
> I don't know if we can fix this in the context of sys_mount. But we if
> we are redoing the option parsing of how we mount filesystems this needs
> to be fixed before we start worrying about bug compatibility.
> Hopefully this report is simple and clear enough that we can at least
> agree on the problem.
> Eric

This might be related to a problem that syzbot is failing to reproduce a problem.!msg/syzkaller-bugs/R03vI7RCVco/0PijCTrcCgAJ

syzbot found a reproducer, and the reproducer was working until next-20180803.
But the reproducer is failing to reproduce this problem in next-20180806 despite
there is no mm related change between next-20180803 and next-20180806.

Therefore, I suspect that the reproducer is no longer working as intended. And
there was parser change (David Howells' patch) between next-20180803 and next-20180806.

I'm waiting for response from David Howells...