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From: "Michael S. Tsirkin" <mst@redhat.com>
To: syzbot <syzbot+3140b17cb44a7b174008@syzkaller.appspotmail.com>
Cc: kvm@vger.kernel.org, netdev@vger.kernel.org,
	syzkaller-bugs@googlegroups.com, linux-kernel@vger.kernel.org,
	virtualization@lists.linux-foundation.org
Subject: Re: [syzbot] kernel BUG in vhost_get_vq_desc
Date: Fri, 18 Feb 2022 06:37:26 -0500	[thread overview]
Message-ID: <20220218063352-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <0000000000003b07b305d840b30f@google.com>

On Thu, Feb 17, 2022 at 05:21:20PM -0800, syzbot wrote:
> syzbot has found a reproducer for the following issue on:
> 
> HEAD commit:    f71077a4d84b Merge tag 'mmc-v5.17-rc1-2' of git://git.kern..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=104c04ca700000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=a78b064590b9f912
> dashboard link: https://syzkaller.appspot.com/bug?extid=3140b17cb44a7b174008
> compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1362e232700000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11373a6c700000
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+3140b17cb44a7b174008@syzkaller.appspotmail.com
> 
> ------------[ cut here ]------------
> kernel BUG at drivers/vhost/vhost.c:2335!
> invalid opcode: 0000 [#1] PREEMPT SMP KASAN
> CPU: 1 PID: 3597 Comm: vhost-3596 Not tainted 5.17.0-rc4-syzkaller-00054-gf71077a4d84b #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> RIP: 0010:vhost_get_vq_desc+0x1d43/0x22c0 drivers/vhost/vhost.c:2335
> Code: 00 00 00 48 c7 c6 20 2c 9d 8a 48 c7 c7 98 a6 8e 8d 48 89 ca 48 c1 e1 04 48 01 d9 e8 b7 59 28 fd e9 74 ff ff ff e8 5d c8 a1 fa <0f> 0b e8 56 c8 a1 fa 48 8b 54 24 18 48 b8 00 00 00 00 00 fc ff df
> RSP: 0018:ffffc90001d1fb88 EFLAGS: 00010293
> RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000
> RDX: ffff8880234b0000 RSI: ffffffff86d715c3 RDI: 0000000000000003
> RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
> R10: ffffffff86d706bc R11: 0000000000000000 R12: ffff888072c24d68
> R13: 0000000000000000 R14: dffffc0000000000 R15: ffff888072c24bb0
> FS:  0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000000000002 CR3: 000000007902c000 CR4: 00000000003506e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  <TASK>
>  vhost_vsock_handle_tx_kick+0x277/0xa20 drivers/vhost/vsock.c:522
>  vhost_worker+0x23d/0x3d0 drivers/vhost/vhost.c:372
>  kthread+0x2e9/0x3a0 kernel/kthread.c:377
>  ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

I don't see how this can trigger normally so I'm assuming
another case of use after free.

>  </TASK>
> Modules linked in:
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:vhost_get_vq_desc+0x1d43/0x22c0 drivers/vhost/vhost.c:2335
> Code: 00 00 00 48 c7 c6 20 2c 9d 8a 48 c7 c7 98 a6 8e 8d 48 89 ca 48 c1 e1 04 48 01 d9 e8 b7 59 28 fd e9 74 ff ff ff e8 5d c8 a1 fa <0f> 0b e8 56 c8 a1 fa 48 8b 54 24 18 48 b8 00 00 00 00 00 fc ff df
> RSP: 0018:ffffc90001d1fb88 EFLAGS: 00010293
> RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000
> RDX: ffff8880234b0000 RSI: ffffffff86d715c3 RDI: 0000000000000003
> RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
> R10: ffffffff86d706bc R11: 0000000000000000 R12: ffff888072c24d68
> R13: 0000000000000000 R14: dffffc0000000000 R15: ffff888072c24bb0
> FS:  0000000000000000(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000000000002 CR3: 000000007902c000 CR4: 00000000003506e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

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       reply	other threads:[~2022-02-18 11:37 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <00000000000070ac6505d7d9f7a8@google.com>
     [not found] ` <0000000000003b07b305d840b30f@google.com>
2022-02-18 11:37   ` Michael S. Tsirkin [this message]
2022-03-02  8:29     ` [syzbot] kernel BUG in vhost_get_vq_desc Lee Jones
2022-03-02  9:18       ` Stefano Garzarella
2022-03-02  9:23         ` Stefano Garzarella

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