Re: [Qemu-devel] [PATCH] vhost: Fix use-after-free in vhost_log_put()

[jsli]

On 2017-06-29 05:12, Marc-André Lureau<address@hidden>wrote:
> Hi
>   
> On Fri, Jun 23, 2017 at 6:28 AM Jia-Shiun 
> Li<address@hidden(mailto:address@hidden)>wrote:
> > In commit 9e0bc24f dev->log_size was reset to zero too early before
> > syncing vhost log. It causes syncing to be skipped.
>   
> ooch, I guess I didn't realize it was also accessing dev->log_size when 
> taking dev->log in local variable.
> I wonder why the code is written this way, it looks like the function may be 
> reentered. For consistency, and perhaps for the reentering case, I would use 
> a local log_size variable too.
> Btw, how did you find this regression?
>   
>   
>   

Ok, it makes sense to prevent reentering. Willregenerate patch.
We are trying to do vhost-scsi migration, and found it to cause 
datainconsistency migrating an i/o stressed guest.

-Jia-Shiun