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SubjectRe: [PATCH] x86: Increase exception stack sizes
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On 2021/9/15 下午11:19, Peter Zijlstra wrote:
> On Wed, Sep 15, 2021 at 03:34:20PM +0800, 王贇 wrote:
>> Hi, Dave, Peter
>>
>> What if we just increase the stack size when ftrace enabled?
>
> I think we can do an unconditional increase. But please first test that
> guard page patch :-)

Nice~ let's focus on the guard one firstly.

Regards,
Michael Wang

>
> ---
> Subject: x86: Increase exception stack sizes
> From: Peter Zijlstra <peterz@infradead.org>
> Date: Wed Sep 15 16:19:46 CEST 2021
>
> It turns out that a single page of stack is trivial to overflow with
> all the tracing gunk enabled. Raise the exception stacks to 2 pages,
> which is still half the interrupt stacks, which are at 4 pages.
>
> Reported-by: Michael Wang <yun.wang@linux.alibaba.com>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
> arch/x86/include/asm/page_64_types.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> --- a/arch/x86/include/asm/page_64_types.h
> +++ b/arch/x86/include/asm/page_64_types.h
> @@ -15,7 +15,7 @@
> #define THREAD_SIZE_ORDER (2 + KASAN_STACK_ORDER)
> #define THREAD_SIZE (PAGE_SIZE << THREAD_SIZE_ORDER)
>
> -#define EXCEPTION_STACK_ORDER (0 + KASAN_STACK_ORDER)
> +#define EXCEPTION_STACK_ORDER (1 + KASAN_STACK_ORDER)
> #define EXCEPTION_STKSZ (PAGE_SIZE << EXCEPTION_STACK_ORDER)
>
> #define IRQ_STACK_ORDER (2 + KASAN_STACK_ORDER)
>

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