From: Nathan Chancellor <natechancellor@gmail.com>
To: Walter Wu <walter-zh.wu@mediatek.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>,
Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Andrey Konovalov <andreyknvl@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
kasan-dev@googlegroups.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
wsd_upstream <wsd_upstream@mediatek.com>,
linux-mediatek@lists.infradead.org,
clang-built-linux@googlegroups.com
Subject: Re: [PATCH] kasan: remove redundant config option
Date: Thu, 7 Jan 2021 14:00:45 -0700 [thread overview]
Message-ID: <20210107210045.GA1456581@ubuntu-m3-large-x86> (raw)
In-Reply-To: <20210107062152.2015-1-walter-zh.wu@mediatek.com>
On Thu, Jan 07, 2021 at 02:21:52PM +0800, Walter Wu wrote:
> CONFIG_KASAN_STACK and CONFIG_KASAN_STACK_ENABLE both enable KASAN
> stack instrumentation, but we should only need one config option,
> so that we remove CONFIG_KASAN_STACK_ENABLE. see [1].
>
> For gcc we could do no prompt and default value y, and for clang
> prompt and default value n.
>
> [1]: https://bugzilla.kernel.org/show_bug.cgi?id=210221
>
> Signed-off-by: Walter Wu <walter-zh.wu@mediatek.com>
> Suggested-by: Dmitry Vyukov <dvyukov@google.com>
> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
> Cc: Dmitry Vyukov <dvyukov@google.com>
> Cc: Andrey Konovalov <andreyknvl@google.com>
> Cc: Alexander Potapenko <glider@google.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> ---
> arch/arm64/kernel/sleep.S | 2 +-
> arch/x86/kernel/acpi/wakeup_64.S | 2 +-
> include/linux/kasan.h | 2 +-
> lib/Kconfig.kasan | 11 ++++-------
> mm/kasan/common.c | 2 +-
> mm/kasan/kasan.h | 2 +-
> mm/kasan/report_generic.c | 2 +-
> scripts/Makefile.kasan | 10 ++++++++--
> 8 files changed, 18 insertions(+), 15 deletions(-)
>
> diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S
> index 6bdef7362c0e..7c44ede122a9 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
>
> -#if defined(CONFIG_KASAN) && CONFIG_KASAN_STACK
> +#if defined(CONFIG_KASAN) && defined(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 5d3a0b8fd379..c7f412f4e07d 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
>
> -#if defined(CONFIG_KASAN) && CONFIG_KASAN_STACK
> +#if defined(CONFIG_KASAN) && defined(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 5e0655fb2a6f..35d1e9b2cbfa 100644
> --- a/include/linux/kasan.h
> +++ b/include/linux/kasan.h
> @@ -302,7 +302,7 @@ static inline void kasan_kfree_large(void *ptr, unsigned long ip) {}
>
> #endif /* CONFIG_KASAN */
>
> -#if defined(CONFIG_KASAN) && CONFIG_KASAN_STACK
> +#if defined(CONFIG_KASAN) && defined(CONFIG_KASAN_STACK)
> void kasan_unpoison_task_stack(struct task_struct *task);
> #else
> static inline void kasan_unpoison_task_stack(struct task_struct *task) {}
> diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
> index f5fa4ba126bf..59de74293454 100644
> --- a/lib/Kconfig.kasan
> +++ b/lib/Kconfig.kasan
> @@ -138,9 +138,11 @@ config KASAN_INLINE
>
> endchoice
>
> -config KASAN_STACK_ENABLE
> - bool "Enable stack instrumentation (unsafe)" if CC_IS_CLANG && !COMPILE_TEST
You are effectively undoing commits 6baec880d7a5 ("kasan: turn off
asan-stack for clang-8 and earlier") and ebb6d35a74ce ("kasan: remove
clang version check for KASAN_STACK") with this change. This change
should still remain around so that all{mod,yes}config remain mostly
clean for clang builds. This should not change anything from the user's
perspective because this option was never user selectable for GCC and
the default y keeps it on.
> +config KASAN_STACK
> + bool "Enable stack instrumentation (unsafe)"
> depends on KASAN_GENERIC || KASAN_SW_TAGS
> + default y if CC_IS_GCC
> + default n if CC_IS_CLANG
This is implied and can be removed.
> help
> The LLVM stack address sanitizer has a know problem that
> causes excessive stack usage in a lot of functions, see
> @@ -154,11 +156,6 @@ config KASAN_STACK_ENABLE
> CONFIG_COMPILE_TEST. On gcc it is assumed to always be safe
> to use and enabled by default.
>
> -config KASAN_STACK
> - int
> - default 1 if KASAN_STACK_ENABLE || CC_IS_GCC
> - default 0
> -
> config KASAN_SW_TAGS_IDENTIFY
> bool "Enable memory corruption identification"
> depends on KASAN_SW_TAGS
> diff --git a/mm/kasan/common.c b/mm/kasan/common.c
> index 38ba2aecd8f4..02ec7f81dc16 100644
> --- a/mm/kasan/common.c
> +++ b/mm/kasan/common.c
> @@ -63,7 +63,7 @@ void __kasan_unpoison_range(const void *address, size_t size)
> unpoison_range(address, size);
> }
>
> -#if CONFIG_KASAN_STACK
> +#if defined(CONFIG_KASAN_STACK)
Isn't '#ifdef CONFIG_...' preferred for CONFIG symbols?
> /* Unpoison the entire stack for a task. */
> void kasan_unpoison_task_stack(struct task_struct *task)
> {
> diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
> index cc4d9e1d49b1..bdfdb1cff653 100644
> --- a/mm/kasan/kasan.h
> +++ b/mm/kasan/kasan.h
> @@ -224,7 +224,7 @@ void *find_first_bad_addr(void *addr, size_t size);
> const char *get_bug_type(struct kasan_access_info *info);
> void metadata_fetch_row(char *buffer, void *row);
>
> -#if defined(CONFIG_KASAN_GENERIC) && CONFIG_KASAN_STACK
> +#if defined(CONFIG_KASAN_GENERIC) && defined(CONFIG_KASAN_STACK)
> void print_address_stack_frame(const void *addr);
> #else
> static inline void print_address_stack_frame(const void *addr) { }
> diff --git a/mm/kasan/report_generic.c b/mm/kasan/report_generic.c
> index 8a9c889872da..137a1dba1978 100644
> --- a/mm/kasan/report_generic.c
> +++ b/mm/kasan/report_generic.c
> @@ -128,7 +128,7 @@ void metadata_fetch_row(char *buffer, void *row)
> memcpy(buffer, kasan_mem_to_shadow(row), META_BYTES_PER_ROW);
> }
>
> -#if CONFIG_KASAN_STACK
> +#if defined(CONFIG_KASAN_STACK)
> static bool __must_check tokenize_frame_descr(const char **frame_descr,
> char *token, size_t max_tok_len,
> unsigned long *value)
> diff --git a/scripts/Makefile.kasan b/scripts/Makefile.kasan
> index 1e000cc2e7b4..abf231d209b1 100644
> --- a/scripts/Makefile.kasan
> +++ b/scripts/Makefile.kasan
> @@ -2,6 +2,12 @@
> CFLAGS_KASAN_NOSANITIZE := -fno-builtin
> KASAN_SHADOW_OFFSET ?= $(CONFIG_KASAN_SHADOW_OFFSET)
>
> +ifdef CONFIG_KASAN_STACK
> + stack_enable := 1
> +else
> + stack_enable := 0
> +endif
> +
> ifdef CONFIG_KASAN_GENERIC
>
> ifdef CONFIG_KASAN_INLINE
> @@ -27,7 +33,7 @@ else
> CFLAGS_KASAN := $(CFLAGS_KASAN_SHADOW) \
> $(call cc-param,asan-globals=1) \
> $(call cc-param,asan-instrumentation-with-call-threshold=$(call_threshold)) \
> - $(call cc-param,asan-stack=$(CONFIG_KASAN_STACK)) \
> + $(call cc-param,asan-stack=$(stack_enable)) \
> $(call cc-param,asan-instrument-allocas=1)
> endif
>
> @@ -42,7 +48,7 @@ else
> endif
>
> CFLAGS_KASAN := -fsanitize=kernel-hwaddress \
> - -mllvm -hwasan-instrument-stack=$(CONFIG_KASAN_STACK) \
> + -mllvm -hwasan-instrument-stack=$(stack_enable) \
> -mllvm -hwasan-use-short-granules=0 \
> $(instrumentation_flags)
>
> --
> 2.18.0
>
next prev parent reply other threads:[~2021-01-07 21:00 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-07 6:21 [PATCH] kasan: remove redundant config option Walter Wu
2021-01-07 21:00 ` Nathan Chancellor [this message]
2021-01-08 1:38 ` Walter Wu
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