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Date:   Thu, 5 Dec 2019 12:50:33 +0100
From:   David Sterba <dsterba@suse.cz>
To:     Johannes Thumshirn <jthumshirn@suse.de>
Cc:     Dmitry Vyukov <dvyukov@google.com>,
        Johannes Thumshirn <jth@kernel.org>,
        syzbot <syzbot+5b658d997a83984507a6@syzkaller.appspotmail.com>,
        Chris Mason <clm@fb.com>, dsterba@suse.com,
        linux-btrfs@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>
Subject: Re: kernel BUG at fs/btrfs/volumes.c:LINE!
Message-ID: <20191205115033.GJ2734@suse.cz>
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On Thu, Dec 05, 2019 at 12:38:38PM +0100, Johannes Thumshirn wrote:
> On Thu, Dec 05, 2019 at 11:07:27AM +0100, Dmitry Vyukov wrote:
> > The correct syntax would be (no dash + colon):
> > 
> > #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/jth/linux.git
> > close_fs_devices
> 
> Ah ok, thanks.
> 
> Although syzbot already said it can't test because it has no reproducer.
> Anyways good to know for future reports.

According to

https://syzkaller.appspot.com/bug?id=d50670eeb21302915bde3f25871dfb7ea43db1e4

there is a way how to test it, many reports and the last one about a
week old. Is there a way to instruct syzbot to run the same tests on a
given branch?

(The reproducer is basically setting up environment with limited amount
of memory available for allocation and this hits the BUG_ON.)