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Subject: Re: ARM Juno r1 + CONFIG_PROVE_LOCKING=y => boot failure
To:     Sudeep Holla <sudeep.holla@arm.com>
Cc:     linux-arm-kernel@lists.infradead.org,
        Liviu Dudau <liviu.dudau@arm.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>
From:   Marek Szyprowski <m.szyprowski@samsung.com>
Message-ID: <d315d99c-ef5d-eae0-86e0-a6d71355ffc1@samsung.com>
Date:   Fri, 11 Oct 2019 12:21:23 +0200
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Hi Sudeep,

On 11.10.2019 12:05, Sudeep Holla wrote:
> Hi Marek,
>
> On Fri, Oct 11, 2019 at 11:26:04AM +0200, Marek Szyprowski wrote:
>> Hi
>>
>> Recently I've got access to ARM Juno R1 board and did some tests with
>> current mainline kernel on it. I'm a bit surprised that enabling
>> CONFIG_PROVE_LOCKING causes a boot failure on this board. After enabling
>> this Kconfig option, I get no single message from the kernel, although I
>> have earlycon enabled.
>>
> I don't have Juno R1 but I tried defconfig + CONFIG_PROVE_LOCKING and
> it boots fine.
>
> So if you disable CONFIG_PROVE_LOCKING(i.e. defconfig) boots fine ?
> Are you using DTB from the mainline ?

Yes, ARM Juno r1 boots fine with pure defconfig and mainline dtb. 
However a few minutes ago I found that it boots with 
v4.14+PROVE_LOCKING, so I will bisect it and share the results.

>> I've did my test with default defconfig and current linux-next,
>> v5.4-rc1, v5.3 and v4.19. In all cases the result is the same. I'm
>> booting kernel using a precompiled uboot from Linaro release and TFTP
>> download.
>>
> OK, I use UEFI+GRUB but I don't think that should cause any issue.
>
>> Is this a known issue? Other ARM64 boards I have access to (Samsung TM2e
>> and RaspberryPi3) boots fine with the same kernel image.
>>
> Not that I am aware of. If you could send me the bootlog with defconfig
> I can take a look and see if I get any clue.
>
Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland