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From: Daniel Borkmann <daniel@iogearbox.net>
To: whiteheadm@acm.org, Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Network Development <netdev@vger.kernel.org>,
	Ingo Molnar <mingo@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Alexei Starovoitov <ast@kernel.org>
Subject: Re: Allocation failure with subsequent kernel crash
Date: Mon, 20 Aug 2018 21:29:45 +0200	[thread overview]
Message-ID: <05825446-e8aa-a983-3fc6-4dc8e81cba57@iogearbox.net> (raw)
In-Reply-To: <CAP8WD_ba1k6uxSFQ00QtW0L23jzjSFw93YpEq+010zKE5sT27g@mail.gmail.com>

Hi Matthew,

On 08/20/2018 08:03 AM, tedheadster wrote:
> On Mon, Aug 20, 2018 at 1:22 AM, Alexei Starovoitov
> <alexei.starovoitov@gmail.com> wrote:
>> I don't remember vzalloc issues that was fixed in this area.
>> 4.14 kernel is quite old. Since then syzbot found few mem
>> related bugs that were fixed.
>> please try to reproduce on the latest tree.
> 
> Alexei,
>   I get this panic with two very recent kernels: 4.18.0 and 4.17.14. I
> do not think this has been fixed. I am still trying to bisect it, but
> sometimes it takes 5 hours for the panic to occur.

I've been looking into it a bit today and still am. Given you've seen
this on x86_32 and also on older kernels, I presume JIT was not involved
(/proc/sys/net/core/bpf_jit_enable is 0). Do you run any specific workload
until you trigger this (e.g. fuzzer on BPF), or any specific event that
triggers at that time after ~5hrs? Or only systemd on idle machine? Have
you managed to reproduce this also elsewhere? Bisect seems indeed painful
but would help tremendously; perhaps also dumping the BPF insns that are
loaded at that point in time.

Thanks a lot,
Daniel

> - Matthew Whitehead
> 


  reply	other threads:[~2018-08-20 19:29 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-17 17:17 Allocation failure with subsequent kernel crash tedheadster
2018-08-20  5:22 ` Alexei Starovoitov
2018-08-20  6:03   ` tedheadster
2018-08-20 19:29     ` Daniel Borkmann [this message]
2018-09-05 14:39       ` tedheadster

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