Re: [PATCH]x86_64 debug_stack nested patch

["bibo,mao" <bibo_mao@linux.intel.com>]

ok, EXCEPTION_STACK_ORDER + 1 is better for me.
in_exception_stack() function is to judge which IST stack by parameter 
stack value, if DEBUG_STKSZ value is set as 8K. The original function 
can not judge whether it is within DEBUG_STACK space.

Thanks
bibo,mao

Jan Beulich wrote:
> Would you mind explaining why you
> - needed to replace the handling of the DEBUG_STKSZ > EXCEPTION_STKSZ in in_exception_stack()?
> - used a hard coded 1 instead of (EXCEPTION_STACK_ORDER + 1) for defining DEBUG_STACK_ORDER?
> 
> Thanks, Jan
> 
>>>> "bibo,mao" <bibo.mao@intel.com> 10.05.06 08:45 >>>
> hi,
> In x86_64 platform, INT1 and INT3 trap stack is IST stack called 
> DEBUG_STACK, when INT1/INT3 trap happens, system will switch to 
> DEBUG_STACK by hardware. Current DEBUG_STACK size is 4K, when int1/int3 
> trap happens, kernel will minus current DEBUG_STACK IST value by 4k. But 
> if int3/int1 trap is nested, it will destroy other vector's IST stack.
> This patch modifies this, it sets DEBUG_STACK size as 8K and allows two 
> level of nested int1/int3 trap.
> Kprobe DEBUG_STACK may be nested, because kprobe hanlder may be probed 
> by other kprobes. This patch is against 2.6.17-rc3.
> 
> Signed-Off-By: bibo, mao <bibo.mao@intel.com>
> 
> Thanks
> bibo,mao
> -
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