Re: [PATCH v1 1/1] QIOChannelSocket: Fix zero-copy send so socket flush works

From: Leonardo Bras Soares Passos <leobras@redhat.com>
To: Peter Xu <peterx@redhat.com>
Cc: "Daniel P. Berrangé" <berrange@redhat.com>,
	qemu-devel <qemu-devel@nongnu.org>,
	徐闯 <xuchuangxclwt@bytedance.com>,
	"Juan Quintela" <quintela@redhat.com>,
	"Dr. David Alan Gilbert" <dgilbert@redhat.com>
Subject: Re: [PATCH v1 1/1] QIOChannelSocket: Fix zero-copy send so socket flush works
Date: Wed, 8 Jun 2022 18:00:51 -0300	[thread overview]
Message-ID: <CAJ6HWG7cEP9f=hifs7rsxdG3789+kSRgDkVJXUY=n3i-U_57AQ@mail.gmail.com> (raw)
In-Reply-To: <YqEMw4NWo3POMK47@xz-m1.local>

On Wed, Jun 8, 2022 at 5:55 PM Peter Xu <peterx@redhat.com> wrote:
>
> On Wed, Jun 08, 2022 at 04:26:10PM -0400, Peter Xu wrote:
> > On Wed, Jun 08, 2022 at 03:18:09PM -0300, Leonardo Bras wrote:
> > > Somewhere between v6 and v7 the of the zero-copy-send patchset a crucial
> > > part of the flushing mechanism got missing: incrementing zero_copy_queued.
> > >
> > > Without that, the flushing interface becomes a no-op, and there is no
> > > garantee the buffer is really sent.
> > >
> > > This can go as bad as causing a corruption in RAM during migration.
> > >
> > > Fixes: 2bc58ffc2926 ("QIOChannelSocket: Implement io_writev zero copy flag & io_flush for CONFIG_LINUX")
> > > Reported-by: 徐闯 <xuchuangxclwt@bytedance.com>
> > > Signed-off-by: Leonardo Bras <leobras@redhat.com>
> >
> > Copy Dave/Juan; Leo please remember to do so in the next posts, or no one
> > will be picking this up. :)
>

Thanks for letting me know.

> My fault, it's an io channel patch.  But still good to copy relevant
> developers..

Np. Sure, I will keep in mind to add them in the next version.

Oh, BTW: I will be sending a v2 shortly.

>
> --
> Peter Xu
>