From: Eric Biggers <ebiggers@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: syzbot <syzbot+3031f712c7ad5dd4d926@syzkaller.appspotmail.com>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: WARNING in filldir64
Date: Mon, 7 Oct 2019 12:19:19 -0700 [thread overview]
Message-ID: <20191007191918.GD16653@gmail.com> (raw)
In-Reply-To: <CAHk-=whtA4bWH=8xY8TAejDR4XyHDux0xH7_y-0jzft0XkvMfw@mail.gmail.com>
On Mon, Oct 07, 2019 at 12:14:33PM -0700, Linus Torvalds wrote:
> On Mon, Oct 7, 2019 at 12:07 PM Eric Biggers <ebiggers@kernel.org> wrote:
> >
> > Seems this indicates a corrupt filesystem rather than a kernel bug, so using
> > WARN_ON is not appropriate. It should either use pr_warn_once(), or be silent.
>
> I was going to silence it for the actual 5.4 release, but I wanted to
> see if anybody actually triggers it.
>
> I didn't really _expect_ it to be triggered, to be honest, so it's
> interesting that it did. What is syzbot doing?
>
> If this is syzbot doing filesystem image randomization, then it falls
> under "ok, expected, ignore it, we'll silence it for 5.4"
>
> But if it's syzbot doing something else, then it would be interesting
> to hear what it's up to.
>
It got there via fat_readdir(), and in the console log there is:
syz_mount_image$vfat(&(0x7f0000000540)='vfat\x00', &(0x7f00000002c0)='./file0\x00', 0x800000000e004, 0x1, &(0x7f0000000140)=[{&(0x7f0000010000)="eb3c906d6b66732e666174000204010002000270fff8", 0x16}], 0x0, 0x0)
So it seems to have generated a corrupt filesystem image and tried to mount it.
- Eric
next prev parent reply other threads:[~2019-10-07 19:19 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-07 14:30 WARNING in filldir64 syzbot
2019-10-07 19:07 ` Eric Biggers
2019-10-07 19:14 ` Linus Torvalds
2019-10-07 19:19 ` Eric Biggers [this message]
2019-10-07 19:24 ` Linus Torvalds
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