Re: [PATCH] earlyprintk=efi,keep fix

From: Andrew Morton
Date: Wed Apr 30 2014 - 15:52:17 EST


On Wed, 30 Apr 2014 10:13:03 +0800 Dave Young <dyoung@xxxxxxxxxx> wrote:

>
> earlyprintk=efi,keep will cause kernel hangs while freeing initmem like below:
> [ 2.826089] VFS: Mounted root (ext4 filesystem) readonly on device 254:2.
> [ 2.846592] devtmpfs: mounted
> [ 2.856974] Freeing unused kernel memory: 880K (ffffffff817d4000 - ffffffff818b0000)
>
> It is caused by efi earlyprintk use __init function which will be freed later.
> Such as early_efi_write is marked as __init, also it will use early_ioremap
> which is init function as well.
>
> To fix this issue, I added one early initcall efi_ioremap_fb which will map the whole
> efi fb for later use. OTOH, adding a wrapper function efi_ioremap which will call
> early_ioremap before ioremap is available.
>
> With this patch applied efi boot ok with earlyprintk=efi,keep console=efi
>

CONFIG_DEBUG_SECTION_MISMATCH should have detected this, but
CONFIG_DEBUG_SECTION_MISMATCH doesn't seem to work any more.
scripts/Makefile.modpost appears to be trying to pass -S to modpost if
CONFIG_DEBUG_SECTION_MISMATCH, but I'm not seeing any warnings. The
CONFIG_DEBUG_SECTION_MISMATCH Kconfig help is not useful. What did we
do?

Shudder. I'll assume Matt will handle this patch?
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