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From:   Dmitry Vyukov <dvyukov@google.com>
Date:   Mon, 8 Feb 2021 15:28:30 +0100
Message-ID: <CACT4Y+Y4rfBqsoF4DDPYoyrZYFzGNO+hNKcu1QkFNcec2VY8xQ@mail.gmail.com>
Subject: Re: linux-next boot error: kernel panic: VFS: Unable to mount root fs
 on unknown-block(0,0)
To:     syzbot <syzbot+b22ad1a79afb8da726c5@syzkaller.appspotmail.com>
Cc:     Jens Axboe <axboe@kernel.dk>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Hannes Reinecke <hare@suse.de>, Jan Kara <jack@suse.cz>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux-Next Mailing List <linux-next@vger.kernel.org>,
        Stephen Rothwell <sfr@canb.auug.org.au>,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
        Tejun Heo <tj@kernel.org>
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On Mon, Feb 8, 2021 at 2:39 PM syzbot
<syzbot+b22ad1a79afb8da726c5@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    8d374d0d Add linux-next specific files for 20210208
> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=13de8a40d00000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=ced6adcf6aff98d6
> dashboard link: https://syzkaller.appspot.com/bug?extid=b22ad1a79afb8da726c5
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+b22ad1a79afb8da726c5@syzkaller.appspotmail.com
>
> netconsole: network logging started
> gtp: GTP module loaded (pdp ctx size 104 bytes)
> rdma_rxe: loaded
> cfg80211: Loading compiled-in X.509 certificates for regulatory database
> cfg80211: Loaded X.509 cert 'sforshee: 00b28ddf47aef9cea7'
> ALSA device list:
>   #0: Dummy 1
>   #1: Loopback 1
>   #2: Virtual MIDI Card 1
> md: Waiting for all devices to be available before autodetect
> md: If you don't use raid, use raid=noautodetect
> md: Autodetecting RAID arrays.
> md: autorun ...
> md: ... autorun DONE.
> VFS: Cannot open root device "sda1" or unknown-block(0,0): error -6

Has anything changed in linux-next related to block devices?... It was
supposed to boot from a standard GCE VM disk, but it does not seem to
be probed by the kernel (should be /dev/sda).

> Please append a correct "root=" boot option; here are the available partitions:
> 0100            4096 ram0
>  (driver?)
> 0101            4096 ram1
>  (driver?)
> 0102            4096 ram2
>  (driver?)
> 0103            4096 ram3
>  (driver?)
> 0104            4096 ram4
>  (driver?)
> 0105            4096 ram5
>  (driver?)
> 0106            4096 ram6
>  (driver?)
> 0107            4096 ram7
>  (driver?)
> 0108            4096 ram8
>  (driver?)
> 0109            4096 ram9
>  (driver?)
> 010a            4096 ram10
>  (driver?)
> 010b            4096 ram11
>  (driver?)
> 010c            4096 ram12
>  (driver?)
> 010d            4096 ram13
>  (driver?)
> 010e            4096 ram14
>  (driver?)
> 010f            4096 ram15
>  (driver?)
> 1f00             128 mtdblock0
>  (driver?)
> Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
> CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.11.0-rc6-next-20210208-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> Call Trace:
>  __dump_stack lib/dump_stack.c:79 [inline]
>  dump_stack+0x107/0x163 lib/dump_stack.c:120
>  panic+0x306/0x73d kernel/panic.c:231
>  mount_block_root+0x3f8/0x4dd init/do_mounts.c:445
>  mount_root+0x1af/0x1f5 init/do_mounts.c:561
>  prepare_namespace+0x1ff/0x234 init/do_mounts.c:613
>  kernel_init_freeable+0x671/0x689 init/main.c:1550
>  kernel_init+0xd/0x1b8 init/main.c:1426
>  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296
> Kernel Offset: disabled
> Rebooting in 86400 seconds..
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@googlegroups.com.
>
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
>
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