On Mon, Nov 16, 2020 at 1:16 PM Catalin Marinas <catalin.marinas@xxxxxxx> wrote: > > On Mon, Nov 16, 2020 at 12:50:00PM +0100, Marco Elver wrote: > > On Mon, 16 Nov 2020 at 11:59, Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote: > > > On Thu, Oct 29, 2020 at 8:57 PM 'Andrey Konovalov' via kasan-dev > > > <kasan-dev@xxxxxxxxxxxxxxxx> wrote: > > > > On Tue, Oct 27, 2020 at 1:44 PM Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote: > > > > > > > > > > On Thu, Oct 22, 2020 at 3:19 PM Andrey Konovalov <andreyknvl@xxxxxxxxxx> wrote: > > > > > > > > > > > > There's a config option CONFIG_KASAN_STACK that has to be enabled for > > > > > > KASAN to use stack instrumentation and perform validity checks for > > > > > > stack variables. > > > > > > > > > > > > There's no need to unpoison stack when CONFIG_KASAN_STACK is not enabled. > > > > > > Only call kasan_unpoison_task_stack[_below]() when CONFIG_KASAN_STACK is > > > > > > enabled. > > > > > > > > > > > > Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> > > > > > > Link: https://linux-review.googlesource.com/id/If8a891e9fe01ea543e00b576852685afec0887e3 > > > > > > --- > > > > > > arch/arm64/kernel/sleep.S | 2 +- > > > > > > arch/x86/kernel/acpi/wakeup_64.S | 2 +- > > > > > > include/linux/kasan.h | 10 ++++++---- > > > > > > mm/kasan/common.c | 2 ++ > > > > > > 4 files changed, 10 insertions(+), 6 deletions(-) > > > > > > > > > > > > diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S > > > > > > index ba40d57757d6..bdadfa56b40e 100644 > > > > > > --- a/arch/arm64/kernel/sleep.S > > > > > > +++ b/arch/arm64/kernel/sleep.S > > > > > > @@ -133,7 +133,7 @@ SYM_FUNC_START(_cpu_resume) > > > > > > */ > > > > > > bl cpu_do_resume > > > > > > > > > > > > -#ifdef CONFIG_KASAN > > > > > > +#if defined(CONFIG_KASAN) && CONFIG_KASAN_STACK > > > > > > mov x0, sp > > > > > > bl kasan_unpoison_task_stack_below > > > > > > #endif > > > > > > diff --git a/arch/x86/kernel/acpi/wakeup_64.S b/arch/x86/kernel/acpi/wakeup_64.S > > > > > > index c8daa92f38dc..5d3a0b8fd379 100644 > > > > > > --- a/arch/x86/kernel/acpi/wakeup_64.S > > > > > > +++ b/arch/x86/kernel/acpi/wakeup_64.S > > > > > > @@ -112,7 +112,7 @@ SYM_FUNC_START(do_suspend_lowlevel) > > > > > > movq pt_regs_r14(%rax), %r14 > > > > > > movq pt_regs_r15(%rax), %r15 > > > > > > > > > > > > -#ifdef CONFIG_KASAN > > > > > > +#if defined(CONFIG_KASAN) && CONFIG_KASAN_STACK > > > > > > /* > > > > > > * The suspend path may have poisoned some areas deeper in the stack, > > > > > > * which we now need to unpoison. > > > > > > diff --git a/include/linux/kasan.h b/include/linux/kasan.h > > > > > > index 3f3f541e5d5f..7be9fb9146ac 100644 > > > > > > --- a/include/linux/kasan.h > > > > > > +++ b/include/linux/kasan.h > > > > > > @@ -68,8 +68,6 @@ static inline void kasan_disable_current(void) {} > > > > > > > > > > > > void kasan_unpoison_memory(const void *address, size_t size); > > > > > > > > > > > > -void kasan_unpoison_task_stack(struct task_struct *task); > > > > > > - > > > > > > void kasan_alloc_pages(struct page *page, unsigned int order); > > > > > > void kasan_free_pages(struct page *page, unsigned int order); > > > > > > > > > > > > @@ -114,8 +112,6 @@ void kasan_restore_multi_shot(bool enabled); > > > > > > > > > > > > static inline void kasan_unpoison_memory(const void *address, size_t size) {} > > > > > > > > > > > > -static inline void kasan_unpoison_task_stack(struct task_struct *task) {} > > > > > > - > > > > > > static inline void kasan_alloc_pages(struct page *page, unsigned int order) {} > > > > > > static inline void kasan_free_pages(struct page *page, unsigned int order) {} > > > > > > > > > > > > @@ -167,6 +163,12 @@ static inline size_t kasan_metadata_size(struct kmem_cache *cache) { return 0; } > > > > > > > > > > > > #endif /* CONFIG_KASAN */ > > > > > > > > > > > > +#if defined(CONFIG_KASAN) && CONFIG_KASAN_STACK > > > > > > > > > > && defined(CONFIG_KASAN_STACK) for consistency > > > > > > > > CONFIG_KASAN_STACK is different from other KASAN configs. It's always > > > > defined, and its value is what controls whether stack instrumentation > > > > is enabled. > > > > > > Not sure why we did this instead of the following, but okay. > > > > > > config KASAN_STACK > > > - int > > > - default 1 if KASAN_STACK_ENABLE || CC_IS_GCC > > > - default 0 > > > + bool > > > + default y if KASAN_STACK_ENABLE || CC_IS_GCC > > > + default n > > > > I wondered the same, but then looking at scripts/Makefile.kasan I > > think it's because we directly pass it to the compiler: > > ... > > $(call cc-param,asan-stack=$(CONFIG_KASAN_STACK)) \ > > ... > > Try this instead: > > $(call cc-param,asan-stack=$(if $(CONFIG_KASAN_STACK),1,0)) \ We could have just 1 config instead of 2 as well. For gcc we could do no prompt and default value y, and for clang -- prompt and default value n. I think it should do what we need.
