From: "Ard Biesheuvel" <ard.biesheuvel@arm.com>
To: jejb@linux.ibm.com, devel@edk2.groups.io
Cc: Bret Barkelew <brbarkel@microsoft.com>,
"Liming Gao (Byosoft address)" <gaoliming@byosoft.com.cn>,
Laszlo Ersek <lersek@redhat.com>
Subject: Re: [PATCH] MdeModulePkg: Fix runtime panic in ValidateSetVariable()
Date: Wed, 25 Nov 2020 22:05:50 +0100 [thread overview]
Message-ID: <1b9adc6f-37e3-0a9b-29cc-2c97e8a9e0f5@arm.com> (raw)
In-Reply-To: <414b7574bf8249de0cecd16fb422c711feb76e1a.camel@linux.ibm.com>
On 11/25/20 9:13 PM, James Bottomley wrote:
> The current variable policy is allocated by AllocatePool(), which is
> boot time only. This means that if you do any variable setting in the
> runtime, the policy has been freed. Ordinarily this isn't detected
> because freed memory is still there, but when you boot the Linux
> kernel, it's been remapped so the actual memory no longer exists in
> the memory map causing a page fault.
>
> Fix this by making it AllocateRuntimePool(). For SMM drivers, the
> platform DSC is responsible for resolving the MemoryAllocationLib
> class to the SmmMemoryAllocationLib instance. In the
> SmmMemoryAllocationLib instance, AllocatePool() and
> AllocateRuntimePool() are implemented identically. Therefore this
> change is a no-op when the RegisterVariablePolicy() function is built
> into an SMM driver. The fix affects runtime DXE drivers only.
>
> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3092
> Signed-off-by: James Bottomley <jejb@linux.ibm.com>
Thanks James
Acked-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
> ---
> MdeModulePkg/Library/VariablePolicyLib/VariablePolicyLib.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/MdeModulePkg/Library/VariablePolicyLib/VariablePolicyLib.c b/MdeModulePkg/Library/VariablePolicyLib/VariablePolicyLib.c
> index 5029ddb96adb..12944ac7ea81 100644
> --- a/MdeModulePkg/Library/VariablePolicyLib/VariablePolicyLib.c
> +++ b/MdeModulePkg/Library/VariablePolicyLib/VariablePolicyLib.c
> @@ -411,7 +411,7 @@ RegisterVariablePolicy (
> }
>
> // Reallocate and copy the table.
> - NewTable = AllocatePool( NewSize );
> + NewTable = AllocateRuntimePool( NewSize );
> if (NewTable == NULL) {
> return EFI_OUT_OF_RESOURCES;
> }
>
BTW I wouldn't mind if the whitespace gets fixed up here at merge time.
next prev parent reply other threads:[~2020-11-25 21:06 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-25 20:13 [PATCH] MdeModulePkg: Fix runtime panic in ValidateSetVariable() James Bottomley
2020-11-25 21:00 ` Laszlo Ersek
2020-11-26 1:23 ` 回复: " gaoliming
[not found] ` <164AEA4706B9EEF6.8857@groups.io>
2020-11-27 0:58 ` 回复: [edk2-devel] " gaoliming
2020-11-25 21:05 ` Ard Biesheuvel [this message]
2020-11-25 21:17 ` Laszlo Ersek
2020-12-01 21:12 ` [EXTERNAL] Re: [edk2-devel] " Bret Barkelew
2020-12-03 10:39 ` Laszlo Ersek
2020-12-03 11:25 ` Ard Biesheuvel
2020-12-03 23:33 ` Laszlo Ersek
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