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From: Naresh Kamboju <naresh.kamboju@linaro.org>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Kuniyuki Iwashima <kuniyu@amazon.com>,
	Jakub Kicinski <kuba@kernel.org>,
	Anders Roxell <anders.roxell@linaro.org>,
	Dan Carpenter <dan.carpenter@linaro.org>,
	"David S . Miller" <davem@davemloft.net>,
	linux-kernel@vger.kernel.org, lkft-triage@lists.linaro.org,
	Xin Long <lucien.xin@gmail.com>,
	Martin KaFai Lau <martin.lau@linux.dev>,
	Netdev <netdev@vger.kernel.org>,
	stable@vger.kernel.org, willemdebruijn.kernel@gmail.com
Subject: Re: selftests: net: udpgso_bench.sh: RIP: 0010:lookup_reuseport
Date: Sat, 27 May 2023 23:32:23 +0530	[thread overview]
Message-ID: <CA+G9fYtzjP_EOjDFZYwTMjv5f3AK2pA_E6mk_mU5FQcZgo_qXQ@mail.gmail.com> (raw)
In-Reply-To: <f0194cbe-eb5b-40ee-8723-1927ebddefc1@app.fastmail.com>

Hi Arnd,

On Sat, 27 May 2023 at 15:03, Arnd Bergmann <arnd@arndb.de> wrote:
>
> On Sat, May 27, 2023, at 05:49, Kuniyuki Iwashima wrote:
> > From: Jakub Kicinski <kuba@kernel.org>
> > Date: Fri, 26 May 2023 20:16:07 -0700
> >> On Wed, 24 May 2023 13:24:15 +0530 Naresh Kamboju wrote:
> >> > While running selftests: net: udpgso_bench.sh on qemu-x86_64 the following
> >> > kernel crash noticed on stable rc 6.3.4-rc2 kernel.
> >>
> >> Can you repro this or it's just a one-off?
> >>
> >> Adding some experts to CC.
> >
> > FWIW, I couldn't reproduce it on my x86_64 QEMU setup & 6.4.0-rc3
> > at least 5 times, so maybe one-off ?
>
> This looks like one of several spurious reports that lkft has produced
> recently, where an 'int3' trap instruction is executed in a function
> that is live-patched, but at a point where the int3 is not expected.
>
> Anders managed to get a reproducer for one of these on his manchine
> yesterday, and has narrowed it down to failing on qemu-7.2.2 but
> not failing on qemu-8.0.

This is an added advantage to tests on multiple qemu versions
and comparing the difference in test results.
Thanks, Anders.

>
> The current theory right now is that this is a qemu bug when
> dealing with self-modifying x86 code that has been fixed in
> qemu-8.0 already, and my suggestion would be to ignore all bugs
> found by lkft that involve an 'int3' trap, and instead change
> the lkft setup to use either qemu-8.0 or run the test systems
> in kvm (which would also be much faster and save resources).

 I will send out an update to ignore the 'int3' trap email reports.

>
> Someone still needs to get to the bottom of this bug to see
> if it's in qemu or in the kernel livepatching code, but I'm
> sure it has nothing to do with the ipv6 stack.

Thank you Arnd.

- Naresh

>       Arnd

  reply	other threads:[~2023-05-27 18:03 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-24  7:54 selftests: net: udpgso_bench.sh: RIP: 0010:lookup_reuseport Naresh Kamboju
2023-05-27  3:16 ` Jakub Kicinski
2023-05-27  3:49   ` Kuniyuki Iwashima
2023-05-27  9:33     ` Arnd Bergmann
2023-05-27 18:02       ` Naresh Kamboju [this message]
2023-05-27 18:39         ` Arnd Bergmann

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