[PATCH] Support asan-fixed-shadow-offset in GCC

Andrey Ryabinin a.ryabinin@samsung.com
Tue Jul 22 10:31:00 GMT 2014


On 07/21/14 23:00, Alexey Preobrazhensky wrote:
> Hi all,
> 
> This patch adds support for non-fixed shadow in asan stack instrumentation.
> 
> It is required for Kernel AddressSanitizer, as the shadow offset is
> not known at the compile time,

To get shadow offset this patch uses function __asan_get_shadow_ptr.
Wouldn't be more effective just to read variable instead of function call?

> and the shadow may not be allocated
> during the early boot stages.
> 

It's true for now, but at some future point I want to make shadow's allocation very early,
before running any instrumented code, so check for __asan_get_shadow_ptr() == 0 will be useless.


> This option is intended to be triggered by -fsanitize=kernel-address
> option, together with enabling instrumentation with calls.
> 
> Bootstrapped&regtested on x86_64.
> 
> Codereview: https://codereview.appspot.com/118040043/
> 
> --
> Alexey
> 



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