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. > > > +void kasan_unpoison_task_stack(struct task_struct *task); > > +#else > > +static inline void kasan_unpoison_task_stack(struct task_struct *task) {} > > +#endif > > + > > #ifdef CONFIG_KASAN_GENERIC > > > > void kasan_cache_shrink(struct kmem_cache *cache); > > diff --git a/mm/kasan/common.c b/mm/kasan/common.c > > index a880e5a547ed..a3e67d49b893 100644 > > --- a/mm/kasan/common.c > > +++ b/mm/kasan/common.c > > @@ -58,6 +58,7 @@ void kasan_disable_current(void) > > } > > #endif /* CONFIG_KASAN_GENERIC || CONFIG_KASAN_SW_TAGS */ > > > > +#if CONFIG_KASAN_STACK > > #ifdef CONFIG_ is the form used toughout the kernel code > > > static void __kasan_unpoison_stack(struct task_struct *task, const void *sp) > > { > > void *base = task_stack_page(task); > > @@ -84,6 +85,7 @@ asmlinkage void kasan_unpoison_task_stack_below(const void *watermark) > > > > kasan_unpoison_memory(base, watermark - base); > > } > > +#endif /* CONFIG_KASAN_STACK */ > > > > void kasan_alloc_pages(struct page *page, unsigned int order) > > { > > -- > > 2.29.0.rc1.297.gfa9743e501-goog > >
