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Date:   Wed, 11 Nov 2020 18:37:42 +0900
From:   Masami Hiramatsu <mhiramat@kernel.org>
To:     Chen Yu <yu.chen.surf@gmail.com>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: bootconfig length parse error in kernel
Message-Id: <20201111183742.e7c90597216343d9d2ffcb4e@kernel.org>
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Hi Chen,

On Tue, 10 Nov 2020 23:39:53 +0800
Chen Yu <yu.chen.surf@gmail.com> wrote:

> Hi Masami,
> Thanks for writing bootconfig and it is useful for boot up trace event
> debugging.

Thanks for testing!

> However it was found that on 5.10-rc2 the bootconfig does not work and it shows
> "'bootconfig' found on command line, but no bootconfig found"
> And the reason for this is the kernel found the magic number to be incorrect.
> I've added some hack in kernel to dump the first 12 bytes, it shows:
> "OTCONFIG". So printed more content ahead we can find
> "#BOOTCONFIG" ahead. So it looks that there is some alignment during
> initrd load, and get_boot_config_from_initrd() might also deal with it. That is
> to say:
> data = (char *)initrd_end - BOOTCONFIG_MAGIC_LEN;
> might do some alignment?

Hrm, interesting. So initrd_end might be aligned. Could you print out the
actuall address of initrd_end? And could you tell me which platform are
you tested?

Thank you,

-- 
Masami Hiramatsu <mhiramat@kernel.org>