linux-kernel - Re: vhost changes (batched) in linux-next after 12/13 trigger random crashes in KVM guests after reboot

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <fe6e7e90-3004-eb7a-9ed8-b53a7667959f@de.ibm.com>
Date:   Tue, 7 Jan 2020 13:16:50 +0100
From:   Christian Borntraeger <borntraeger@...ibm.com>
To:     "Michael S. Tsirkin" <mst@...hat.com>
Cc:     "virtualization@...ts.linux-foundation.org" 
        <virtualization@...ts.linux-foundation.org>,
        Stephen Rothwell <sfr@...b.auug.org.au>,
        Linux Next Mailing List <linux-next@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        kvm list <kvm@...r.kernel.org>,
        Halil Pasic <pasic@...ux.ibm.com>
Subject: Re: vhost changes (batched) in linux-next after 12/13 trigger random
 crashes in KVM guests after reboot

On 07.01.20 12:55, Michael S. Tsirkin wrote:

> 
> I pushed batched-v3 - same head but bisect should work now.
> 

With 
commit 38ced0208491103b50f1056f0d1c8f28e2e13d08 (HEAD)
Author:     Michael S. Tsirkin <mst@...hat.com>
AuthorDate: Wed Dec 11 12:19:26 2019 -0500
Commit:     Michael S. Tsirkin <mst@...hat.com>
CommitDate: Tue Jan 7 06:52:42 2020 -0500

    vhost: use batched version by default


I have exactly one successful ping and then the network inside the guest is broken (no packet
anymore).

So you could consider this commit broken (but in a different way and also without any
guest reboot necessary).


bisect log:
git bisect start
# bad: [d2f6175f52062ee51ee69754a6925608213475d2] vhost: use vhost_desc instead of vhost_log
git bisect bad d2f6175f52062ee51ee69754a6925608213475d2
# good: [d1281e3a562ec6a08f944a876481dd043ba739b9] virtio-blk: remove VIRTIO_BLK_F_SCSI support
git bisect good d1281e3a562ec6a08f944a876481dd043ba739b9
# good: [fac7c0f46996e32d996f5c46121df24a6b95ec3b] vhost: option to fetch descriptors through an independent struct
git bisect good fac7c0f46996e32d996f5c46121df24a6b95ec3b
# bad: [539eb9d738f048cd7be61f404e8f9c7d9d2ff3cc] vhost: batching fetches
git bisect bad 539eb9d738f048cd7be61f404e8f9c7d9d2ff3cc