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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Thu, 20 Jul 2023 15:53:46 -0700
Message-ID: <CAHk-=wg7DSNsHY6tWc=WLeqDBYtXges_12fFk1c+-No+fZ0xYQ@mail.gmail.com>
Subject: Re: [syzbot] [hfs?] WARNING in hfs_write_inode
To:     Matthew Wilcox <willy@infradead.org>
Cc:     Jeffrey Walton <noloader@gmail.com>,
        John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>,
        Dmitry Vyukov <dvyukov@google.com>,
        Viacheslav Dubeyko <slava@dubeyko.com>,
        Arnd Bergmann <arnd@arndb.de>,
        syzbot <syzbot+7bb7cd3595533513a9e7@syzkaller.appspotmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        christian.brauner@ubuntu.com,
        Damien Le Moal <damien.lemoal@opensource.wdc.com>,
        Jeff Layton <jlayton@kernel.org>,
        Linux FS Devel <linux-fsdevel@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        syzkaller-bugs@googlegroups.com,
        ZhangPeng <zhangpeng362@huawei.com>,
        linux-m68k@lists.linux-m68k.org,
        debian-ports <debian-ports@lists.debian.org>
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On Thu, 20 Jul 2023 at 15:37, Matthew Wilcox <willy@infradead.org> wrote:
>
> I think you're missing the context.  There are bugs in how this filesystem
> handles intentionally-corrupted filesystems.  That's being reported as
> a critical bug because apparently some distributions automount HFS/HFS+
> filesystems presented to them on a USB key.  Nobody is being paid to fix
> these bugs.  Nobody is volunteering to fix these bugs out of the kindness
> of their heart.  What choice do we have but to remove the filesystem,
> regardless of how many happy users it has?

You're being silly.

We have tons of sane options. The obvious one is "just don't mount
untrusted media".

Now, the kernel doesn't know which media is trusted or not, since the
kernel doesn't actually see things like /etc/mtab and friends. So we
in the kernel can't do that, but distros should have a very easy time
just fixing their crazy models.

Saying that the kernel should remove a completely fine filesystem just
because some crazy use-cases that nobody cares about are broken, now
*that* just crazy.

Now, would it be good to have a maintainer for hgs? Obviously. But no,
we don't remove filesystems just because they don't have maintainers.

And no, we have not suddenly started saying "users don't matter".

          Linus