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From:   Chen Yu <yu.chen.surf@gmail.com>
Date:   Tue, 10 Nov 2020 23:39:53 +0800
Message-ID: <CADjb_WSwW4jrNvLp91YHu-qimU1P1itPU_gZ5juQRWER_vGWAA@mail.gmail.com>
Subject: bootconfig length parse error in kernel
To:     Masami Hiramatsu <mhiramat@kernel.org>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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Hi Masami,
Thanks for writing bootconfig and it is useful for boot up trace event
debugging.
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?


-- 
Thanks,
Chenyu