Re: [PATCH] ipv4/mptcp: fix divide error
From: Jiang Biao
Date: Wed Aug 25 2021 - 23:22:39 EST
On Thu, 26 Aug 2021 at 01:56, Mat Martineau
> On Tue, 24 Aug 2021, Jiang Biao wrote:
> > Hi,
> > On Tue, 24 Aug 2021 at 15:36, Matthieu Baerts
> > <matthieu.baerts@xxxxxxxxxxxx> wrote:
> >> Hi Jiang,
> >> On 24/08/2021 09:19, Jiang Biao wrote:
> >> (...)
> >>> There is a fix divide error reported,
> >>> divide error: 0000 [#1] PREEMPT SMP KASAN
> >>> RIP: 0010:tcp_tso_autosize build/../net/ipv4/tcp_output.c:1975 [inline]
> >>> RIP: 0010:tcp_tso_segs+0x14f/0x250 build/../net/ipv4/tcp_output.c:1992
> >> Thank you for this patch and validating MPTCP on your side!
> >> This issue is actively tracked on our Github project  and a patch is
> >> already in our tree  but still under validation.
> >>> It's introduced by non-initialized info->mss_now in __mptcp_push_pending.
> >>> Fix it by adding protection in mptcp_push_release.
> >> Indeed, you are right, info->mss_now can be set to 0 in some cases but
> >> that's not normal.
> >> Instead of adding a protection here, we preferred fixing the root cause,
> >> see . Do not hesitate to have a look at the other patch and comment
> >> there if you don't agree with this version.
> >> Except if  is difficult to backport, I think we don't need your extra
> >> protection. WDYT?
> > Agreed, fixing the root cause is much better.
> > Thanks for the reply.
> Hi Jiang -
> Could you try cherry-picking this commit to see if it eliminates the error
> in your system?
ok, I'll try and give you feedback.