From: Robin Murphy <robin.murphy@arm.com>
To: Vicente Bergas <vicencb@gmail.com>, Marc Zyngier <marc.zyngier@arm.com>
Cc: Matthias Brugger <mbrugger@suse.com>,
Heiko Stuebner <heiko@sntech.de>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
linux-rockchip@lists.infradead.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: kexec on rk3399
Date: Mon, 22 Jul 2019 18:35:01 +0100 [thread overview]
Message-ID: <8f71e7de-7eaf-58c7-6471-c8eb01e656ce@arm.com> (raw)
In-Reply-To: <d5959b93-40ce-455c-877e-c661a3f22351@gmail.com>
On 22/07/2019 18:05, Vicente Bergas wrote:
> On Monday, July 22, 2019 4:54:41 PM CEST, Marc Zyngier wrote:
>> On 22/07/2019 15:31, Vicente Bergas wrote:
>>> Hi, i have been running linux on rk3399 booted with kexec fine until 5.2
>>> From 5.2 onwards, there are memory corruption issues as reported here:
>>> http://lkml.iu.edu/hypermail/linux/kernel/1906.2/07211.html
>>> kexec has been identified as the principal reason for the issues.
>>>
>>> It turns out that kexec has never worked reliably on this platform, ...
>>
>> Not the most trusted version, but hey, why not...
>>
>>> 2.- Kexec into v5.2.2
>>> 3.- The kernel reports nothing (earlycon not enabled) and does not
>>> boot.
>>> The same kernel v5.2.2 works fine when booted without kexec.
>>
>> Can you please enable earlycon and let us know how far it goes? Your
>> previous reports hinting at runtime memory corruption, but this seems to
>> be much more radical...
>
> Details on previous email, but basically, earlycon affects reproducibility.
>
> If it is a runtime memory corruption, what are we hunting for? an issue in
> the kernel before kexec or in the kernel after kexec?
The obvious culprit would be DMA devices left running by the first
kernel scribbling over the second kernel's memory before it's had the
chance to reset them. Since boot-time memory allocation patterns tend to
be relatively repeatable for a given platform and kernel configuration,
"random" may well look a lot less random than you might expect, and it
wouldn't be unheard of for e.g. the second kernel to mostly allocate its
dentry cache from the same area the first kernel was mostly putting a
network Rx descriptor ring.
Robin.
>
>> FWIW, I was able to kexec using 5.2-rcx (for values of x around 6) on a
>> NanoPC-T4, using a mainline u-boot and firmware.
>>
>> Thanks,
>>
>> M.
>
> Regards,
> Vicenç.
>
>
> _______________________________________________
> Linux-rockchip mailing list
> Linux-rockchip@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-rockchip
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next prev parent reply other threads:[~2019-07-22 17:35 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-22 14:31 kexec on rk3399 Vicente Bergas
2019-07-22 14:46 ` Will Deacon
2019-07-22 16:08 ` Vicente Bergas
2019-07-22 14:47 ` Matthias Brugger
2019-07-22 16:56 ` Vicente Bergas
2019-07-22 14:54 ` Marc Zyngier
2019-07-22 17:05 ` Vicente Bergas
2019-07-22 17:35 ` Robin Murphy [this message]
2019-07-22 18:53 ` Vicente Bergas
2019-07-23 13:32 ` Robin Murphy
2019-08-14 12:53 ` Vicente Bergas
2019-08-14 13:06 ` Felipe Balbi
2019-08-14 13:15 ` Vicente Bergas
2019-08-15 6:00 ` Felipe Balbi
2019-08-14 13:12 ` Robin Murphy
2019-08-15 1:15 ` Vicente Bergas
2019-08-15 6:06 ` Felipe Balbi
2019-08-15 11:09 ` Robin Murphy
2019-08-17 17:41 ` [PATCH] usb: dwc3: Add shutdown to platform_driver Vicente Bergas
2019-08-27 11:45 ` Vicente Bergas
2019-08-27 11:53 ` Felipe Balbi
2019-08-27 12:16 ` Vicente Bergas
2019-09-09 15:07 ` Vicente Bergas
2019-10-23 6:31 ` Felipe Balbi
2019-10-24 12:15 ` Vicente Bergas
2019-10-25 10:25 ` Felipe Balbi
2019-10-25 10:42 ` Vicente Bergas
2019-09-19 11:36 ` Vicente Bergas
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