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 :-) --- Subject: x86: Increase exception stack sizes From: Peter Zijlstra <peterz@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> --- 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)
