2020-10-22 20:11:46

by Andrey Konovalov

Subject: [PATCH RFC v2 04/21] kasan: unpoison stack only with CONFIG_KASAN_STACK

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 <[email protected]>
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
+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
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

2020-10-28 07:37:12

by Dmitry Vyukov

Subject: Re: [PATCH RFC v2 04/21] kasan: unpoison stack only with CONFIG_KASAN_STACK

On Thu, Oct 22, 2020 at 3:19 PM Andrey Konovalov <[email protected]> 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 <[email protected]>
> 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
>

2020-10-28 07:37:20

by Dmitry Vyukov

Subject: Re: [PATCH RFC v2 04/21] kasan: unpoison stack only with CONFIG_KASAN_STACK

On Tue, Oct 27, 2020 at 1:44 PM Dmitry Vyukov <[email protected]> wrote:
>
> On Thu, Oct 22, 2020 at 3:19 PM Andrey Konovalov <[email protected]> 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 <[email protected]>
> > 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

And similarly here

> > 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

and here

> > /*
> > * 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
> >

2020-10-29 20:00:48

by Andrey Konovalov

Subject: Re: [PATCH RFC v2 04/21] kasan: unpoison stack only with CONFIG_KASAN_STACK

On Tue, Oct 27, 2020 at 1:44 PM Dmitry Vyukov <[email protected]> wrote:
>
> On Thu, Oct 22, 2020 at 3:19 PM Andrey Konovalov <[email protected]> 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 <[email protected]>
> > 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
> >

2020-11-16 11:53:03

by Marco Elver

Subject: Re: [PATCH RFC v2 04/21] kasan: unpoison stack only with CONFIG_KASAN_STACK

On Mon, 16 Nov 2020 at 11:59, Dmitry Vyukov <[email protected]> wrote:
>
> On Thu, Oct 29, 2020 at 8:57 PM 'Andrey Konovalov' via kasan-dev
> <[email protected]> wrote:
> >
> > On Tue, Oct 27, 2020 at 1:44 PM Dmitry Vyukov <[email protected]> wrote:
> > >
> > > On Thu, Oct 22, 2020 at 3:19 PM Andrey Konovalov <[email protected]> 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 <[email protected]>
> > > > 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)) \
...

2020-11-16 12:22:37

by Dmitry Vyukov

Subject: Re: [PATCH RFC v2 04/21] kasan: unpoison stack only with CONFIG_KASAN_STACK

On Mon, Nov 16, 2020 at 1:16 PM Catalin Marinas <[email protected]> wrote:
>
> On Mon, Nov 16, 2020 at 12:50:00PM +0100, Marco Elver wrote:
> > On Mon, 16 Nov 2020 at 11:59, Dmitry Vyukov <[email protected]> wrote:
> > > On Thu, Oct 29, 2020 at 8:57 PM 'Andrey Konovalov' via kasan-dev
> > > <[email protected]> wrote:
> > > > On Tue, Oct 27, 2020 at 1:44 PM Dmitry Vyukov <[email protected]> wrote:
> > > > >
> > > > > On Thu, Oct 22, 2020 at 3:19 PM Andrey Konovalov <[email protected]> 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 <[email protected]>
> > > > > > 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.

2020-11-16 13:54:12

by Andrey Konovalov

Subject: Re: [PATCH RFC v2 04/21] kasan: unpoison stack only with CONFIG_KASAN_STACK

On Mon, Nov 16, 2020 at 1:42 PM Vincenzo Frascino
<[email protected]> wrote:
>
> >>>>
> >>>> 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.
> >
>
> I agree with Catalin's proposal since it should simplify things.
>
> Nit: 'default n' is the default hence I do not think it should be required
> explicitly.

Fixing this sounds like a good idea, but perhaps not as a part of this
series, to not overinflate it even further.

I've filed a bug for this: https://bugzilla.kernel.org/show_bug.cgi?id=210221

2020-11-16 14:50:29

by Vincenzo Frascino

Subject: Re: [PATCH RFC v2 04/21] kasan: unpoison stack only with CONFIG_KASAN_STACK

On 11/16/20 1:50 PM, Andrey Konovalov wrote:
> Fixing this sounds like a good idea, but perhaps not as a part of this
> series, to not overinflate it even further.
>
> I've filed a bug for this: https://bugzilla.kernel.org/show_bug.cgi?id=210221

Fine by me.

--
Regards,
Vincenzo

2020-11-16 20:10:53

by Vincenzo Frascino

Subject: Re: [PATCH RFC v2 04/21] kasan: unpoison stack only with CONFIG_KASAN_STACK

On 11/16/20 12:19 PM, Dmitry Vyukov wrote:
> On Mon, Nov 16, 2020 at 1:16 PM Catalin Marinas <[email protected]> wrote:
>>
>> On Mon, Nov 16, 2020 at 12:50:00PM +0100, Marco Elver wrote:
>>> On Mon, 16 Nov 2020 at 11:59, Dmitry Vyukov <[email protected]> wrote:
>>>> On Thu, Oct 29, 2020 at 8:57 PM 'Andrey Konovalov' via kasan-dev
>>>> <[email protected]> wrote:
>>>>> On Tue, Oct 27, 2020 at 1:44 PM Dmitry Vyukov <[email protected]> wrote:
>>>>>>
>>>>>> On Thu, Oct 22, 2020 at 3:19 PM Andrey Konovalov <[email protected]> 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 <[email protected]>
>>>>>>> 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.
>

I agree with Catalin's proposal since it should simplify things.

Nit: 'default n' is the default hence I do not think it should be required
explicitly.

--
Regards,
Vincenzo

2020-11-17 01:48:31

by Dmitry Vyukov

Subject: Re: [PATCH RFC v2 04/21] kasan: unpoison stack only with CONFIG_KASAN_STACK

On Thu, Oct 29, 2020 at 8:57 PM 'Andrey Konovalov' via kasan-dev
<[email protected]> wrote:
>
> On Tue, Oct 27, 2020 at 1:44 PM Dmitry Vyukov <[email protected]> wrote:
> >
> > On Thu, Oct 22, 2020 at 3:19 PM Andrey Konovalov <[email protected]> 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 <[email protected]>
> > > 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

2020-11-17 01:50:32

by Catalin Marinas

Subject: Re: [PATCH RFC v2 04/21] kasan: unpoison stack only with CONFIG_KASAN_STACK

On Mon, Nov 16, 2020 at 12:50:00PM +0100, Marco Elver wrote:
> On Mon, 16 Nov 2020 at 11:59, Dmitry Vyukov <[email protected]> wrote:
> > On Thu, Oct 29, 2020 at 8:57 PM 'Andrey Konovalov' via kasan-dev
> > <[email protected]> wrote:
> > > On Tue, Oct 27, 2020 at 1:44 PM Dmitry Vyukov <[email protected]> wrote:
> > > >
> > > > On Thu, Oct 22, 2020 at 3:19 PM Andrey Konovalov <[email protected]> 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 <[email protected]>
> > > > > 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)) \

--
Catalin