Re: [PATCH] x86, efi: retry ExitBootServices() on failure

From: Matt Fleming
Date: Tue Jun 11 2013 - 03:22:30 EST

On Tue, 11 Jun, at 07:52:38AM, Matt Fleming wrote:
> From: Zach Bobroff <zacharyb@xxxxxxx>
> ExitBootServices is absolutely supposed to return a failure if any
> ExitBootServices event handler changes the memory map. Basically the
> get_map loop should run again if ExitBootServices returns an error the
> first time. I would say it would be fair that if ExitBootServices gives
> an error the second time then Linux would be fine in returning control
> back to BIOS.
> The second change is the following line:
> again:
> size += sizeof(*mem_map) * 2;
> Originally you were incrementing it by the size of one memory map entry.
> The issue here is all related to the low_alloc routine you are using.
> In this routine you are making allocations to get the memory map itself.
> Doing this allocation or allocations can affect the memory map by more
> than one record.
> [ mfleming - changelog, code style ]
> Signed-off-by: Zach Bobroff <zacharyb@xxxxxxx>
> Cc: <stable@xxxxxxxxxxxxxxx>
> Signed-off-by: Matt Fleming <matt.fleming@xxxxxxxxx>
> ---
> arch/x86/boot/compressed/eboot.c | 20 +++++++++++++++++---
> 1 file changed, 17 insertions(+), 3 deletions(-)

I've queued this patch up for v3.11 in my 'next' branch.

Matt Fleming, Intel Open Source Technology Center
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