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Subject: Re: [PATCH v15 00/10] arm64: Add kernel probes (kprobes) support
To: Catalin Marinas <catalin.marinas@arm.com>
References: <1467995754-32508-1-git-send-email-dave.long@linaro.org>
 <20160719182744.GI21256@e104818-lin.cambridge.arm.com>
Cc: Huang Shijie <shijie.huang@arm.com>, James Morse <james.morse@arm.com>,
        Marc Zyngier <marc.zyngier@arm.com>,
        Pratyush Anand <panand@redhat.com>,
        Sandeepa Prabhu <sandeepa.s.prabhu@gmail.com>,
        Will Deacon <will.deacon@arm.com>, William Cohen <wcohen@redhat.com>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        Steve Capper <steve.capper@linaro.org>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Li Bin <huawei.libin@huawei.com>, Jisheng Zhang <jszhang@marvell.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Daniel Thompson <daniel.thompson@linaro.org>,
        Vladimir Murzin <Vladimir.Murzin@arm.com>,
        Petr Mladek <pmladek@suse.com>,
        Ard Biesheuvel <ard.biesheuvel@linaro.org>,
        Jens Wiklander <jens.wiklander@linaro.org>,
        Robin Murphy <robin.murphy@arm.com>, Mark Brown <broonie@kernel.org>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Dave P Martin <Dave.Martin@arm.com>,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        yalin wang <yalin.wang2010@gmail.com>, Yang Shi <yang.shi@linaro.org>,
        Zi Shen Lim <zlim.lnx@gmail.com>,
        John Blackwood <john.blackwood@ccur.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        =?UTF-8?Q?Alex_Benn=c3=a9e?= <alex.bennee@linaro.org>,
        Adam Buchbinder <adam.buchbinder@gmail.com>,
        Christoffer Dall <christoffer.dall@linaro.org>
From: David Long <dave.long@linaro.org>
Message-ID: <578E81BE.3060100@linaro.org>
Date: Tue, 19 Jul 2016 15:38:38 -0400
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On 07/19/2016 02:27 PM, Catalin Marinas wrote:
> On Fri, Jul 08, 2016 at 12:35:44PM -0400, David Long wrote:
>> From: "David A. Long" <dave.long@linaro.org>
>>
>> This patchset is heavily based on Sandeepa Prabhu's ARM v8 kprobes patches,
>> first seen in October 2013. This version attempts to address concerns
>> raised by reviewers and also fixes problems discovered during testing.
>>
>> This patchset adds support for kernel probes(kprobes), jump probes(jprobes)
>> and return probes(kretprobes) support for ARM64.
>
> Some more errors with this patchset applied and CONFIG_NET_TCPPROBE
> enabled (it's fine with this option disabled though). I boot on a Juno
> with NFS over UDP and then try to ssh into it (hence establish the first
> TCP connection):
>
> Unable to handle kernel NULL pointer dereference at virtual address 00000003
> pgd = ffff000008ceb000
> [00000003] *pgd=00000009fff6d003, *pud=00000009fff6c003, *pmd=0000000000000000
> Internal error: Oops: 96000004 [#1] PREEMPT SMP
> Modules linked in:
> CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.7.0-rc4+ #9
> Hardware name: ARM Juno development board (r0) (DT)
> task: ffff800976901900 ti: ffff800976910000 task.ti: ffff800976910000
> PC is at enqueue_task_fair+0x818/0x1188
> LR is at enqueue_task_fair+0x8a4/0x1188
> pc : [<ffff0000080e73d8>] lr : [<ffff0000080e7464>] pstate: 600001c5
> sp : ffff80097fec3a80


[...]

I've reproduced the failure on hikey. I'm looking at it.

-dl