Re: [edk2-devel] AArch64 with HeapGuard: page allocations wrongly aligned

["Oliver Smith-Denny" <osde@linux.microsoft.com>]

On 1/22/2024 5:53 PM, Oliver Smith-Denny wrote:> I was able to repro 
your bug (by just turning on page guards on
> ArmVirtQemu, allocating runtime mem and freeing it). I think you
> are the first person to free runtime mem on ARM64 with page guards
> enabled (and to care when it failed :).
> 
> The heap guard code is not written with ARM64 in mind (nor is much of
> the codebase, of course). Specifically in this case the heap guard code
> only wishes to preserve 4 KB alignment, it knows nothing of ARM64's
> runtime page granularity required.
> 
> Let me take a look at this, I'm working on a solution here, but I want
> to test this out further. I'll try to send a patch later this week or
> next.

Ok, got sidetracked, but got back to this. Rebecca, can you create a
bugzilla for this and try this patch:

https://github.com/tianocore/edk2/pull/5339.

I want to get some feedback on it and your testing before I send out a
patch for it. However, it did fix my repro case where I was failing to
free runtime memory with page guard enabled, so I believe it should fix
your case.

I need to fix some minor things like patch check, etc. I also did my
testing on a slightly old version of master, so may need a minor touch
up.

Thanks,
Oliver


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