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 > +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 >
