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From: "Michael S. Tsirkin" <mst@redhat.com>
To: Cornelia Huck <cohuck@redhat.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>,
	eperezma@redhat.com,
	"virtualization@lists.linux-foundation.org" 
	<virtualization@lists.linux-foundation.org>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	Linux Next Mailing List <linux-next@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	kvm list <kvm@vger.kernel.org>, Halil Pasic <pasic@linux.ibm.com>
Subject: Re: vhost changes (batched) in linux-next after 12/13 trigger random crashes in KVM guests after reboot
Date: Fri, 7 Feb 2020 05:07:50 -0500	[thread overview]
Message-ID: <20200207050731-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20200207095353.08bc91e4.cohuck@redhat.com>

On Fri, Feb 07, 2020 at 09:53:53AM +0100, Cornelia Huck wrote:
> On Fri, 7 Feb 2020 09:13:14 +0100
> Christian Borntraeger <borntraeger@de.ibm.com> wrote:
> 
> > On 07.02.20 08:58, Michael S. Tsirkin wrote:
> > > On Fri, Feb 07, 2020 at 08:47:14AM +0100, Christian Borntraeger wrote:  
> > >> Also adding Cornelia.
> > >>
> > >>
> > >> On 06.02.20 23:17, Michael S. Tsirkin wrote:  
> > >>> On Thu, Feb 06, 2020 at 04:12:21PM +0100, Christian Borntraeger wrote:  
> > >>>>
> > >>>>
> > >>>> On 06.02.20 15:22, eperezma@redhat.com wrote:  
> > >>>>> Hi Christian.
> > >>>>>
> > >>>>> Could you try this patch on top of ("38ced0208491 vhost: use batched version by default")?
> > >>>>>
> > >>>>> It will not solve your first random crash but it should help with the lost of network connectivity.
> > >>>>>
> > >>>>> Please let me know how does it goes.  
> > >>>>
> > >>>>
> > >>>> 38ced0208491 + this seem to be ok.
> > >>>>
> > >>>> Not sure if you can make out anything of this (and the previous git bisect log)  
> > >>>
> > >>> Yes it does - that this is just bad split-up of patches, and there's
> > >>> still a real bug that caused worse crashes :)
> > >>>
> > >>> So I just pushed batch-v4.
> > >>> I expect that will fail, and bisect to give us
> > >>>     vhost: batching fetches
> > >>> Can you try that please?
> > >>>  
> > >>
> > >> yes.
> > >>
> > >> eccb852f1fe6bede630e2e4f1a121a81e34354ab is the first bad commit
> > >> commit eccb852f1fe6bede630e2e4f1a121a81e34354ab
> > >> Author: Michael S. Tsirkin <mst@redhat.com>
> > >> Date:   Mon Oct 7 06:11:18 2019 -0400
> > >>
> > >>     vhost: batching fetches
> > >>     
> > >>     With this patch applied, new and old code perform identically.
> > >>     
> > >>     Lots of extra optimizations are now possible, e.g.
> > >>     we can fetch multiple heads with copy_from/to_user now.
> > >>     We can get rid of maintaining the log array.  Etc etc.
> > >>     
> > >>     Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > >>
> > >>  drivers/vhost/test.c  |  2 +-
> > >>  drivers/vhost/vhost.c | 39 ++++++++++++++++++++++++++++++++++-----
> > >>  drivers/vhost/vhost.h |  4 +++-
> > >>  3 files changed, 38 insertions(+), 7 deletions(-)
> > >>  
> > > 
> > > 
> > > And the symptom is still the same - random crashes
> > > after a bit of traffic, right?  
> > 
> > random guest crashes after a reboot of the guests. As if vhost would still
> > write into now stale buffers.
> > 
> 
> I'm late to the party; but where is that commit located? Or has it been
> dropped again already?

my vhost tree. Tag batch-v4.


  reply	other threads:[~2020-02-07 10:08 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-18 14:43 vhost changes (batched) in linux-next after 12/13 trigger random crashes in KVM guests after reboot Christian Borntraeger
2019-12-18 15:10 ` Michael S. Tsirkin
2019-12-18 15:59   ` Christian Borntraeger
2020-01-06 10:50     ` Michael S. Tsirkin
2020-01-07  8:59       ` Christian Borntraeger
2020-01-07  9:39         ` Michael S. Tsirkin
2020-01-07 11:34           ` Christian Borntraeger
2020-01-07 11:47             ` Michael S. Tsirkin
2020-01-07 11:55             ` Michael S. Tsirkin
2020-01-07 12:16               ` Christian Borntraeger
2020-01-20  6:27                 ` Michael S. Tsirkin
2020-01-22 19:32                   ` Christian Borntraeger
2020-02-06 14:22                     ` eperezma
2020-02-06 15:12                       ` Christian Borntraeger
2020-02-06 22:17                         ` Michael S. Tsirkin
2020-02-07  7:47                           ` Christian Borntraeger
2020-02-07  7:58                             ` Michael S. Tsirkin
2020-02-07  8:13                               ` Christian Borntraeger
2020-02-07  8:53                                 ` Cornelia Huck
2020-02-07 10:07                                   ` Michael S. Tsirkin [this message]
     [not found]                                 ` <CAJaqyWfngzP4d01B6+Sqt8FXN6jX7kGegjx8ie4no_1Er3igQA@mail.gmail.com>
2020-02-10 10:09                                   ` Christian Borntraeger
2020-02-10 11:01                                   ` Christian Borntraeger
2020-02-11  9:33                                     ` Eugenio Pérez
2020-02-11  9:56                                       ` Christian Borntraeger
2020-02-11 10:07                                         ` Christian Borntraeger
2020-02-11 13:04                                     ` Eugenio Pérez
2020-02-11 13:13                                       ` Christian Borntraeger
2020-02-12 16:34                                         ` Eugenio Pérez
2020-02-13  9:30                                           ` Christian Borntraeger
2020-02-13 10:47                                             ` Eugenio Pérez
2020-02-13 13:09                                               ` Christian Borntraeger
2020-02-13 16:29                                                 ` Eugenio Pérez
2020-02-13 16:32                                                   ` Christian Borntraeger
2020-02-14  7:06                                                     ` Eugenio Pérez
2020-02-14  7:33                                                       ` Christian Borntraeger
2020-02-14  7:40                                                         ` Eugenio Perez Martin
2020-02-14  7:43                                                           ` Christian Borntraeger
2020-02-14  7:47                                                             ` Christian Borntraeger
2020-02-14 12:17                                                               ` Eugenio Pérez
2020-02-14 12:22                                                                 ` Christian Borntraeger
2020-02-14 12:26                                                                   ` Eugenio Pérez
2020-02-14 12:34                                                                     ` Christian Borntraeger
2020-03-27 11:08                                                                       ` Eugenio Pérez
2020-03-27 15:46                                                                         ` Christian Borntraeger
2020-02-11 13:57                                       ` Michael S. Tsirkin
2020-03-27  8:03                                         ` Eugenio Perez Martin
2020-02-06 22:07                       ` Michael S. Tsirkin

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