kasan: remove kasan_unpoison_stack_above_sp_to() (c0e16ab3) · Commits · 戴 / test

kasan_unpoison_stack_above_sp_to() is defined in kasan code but never used. The function was introduced as part of the commit: commit ("kprobes: Unpoison stack in jprobe_return() for KASAN") ... where it was necessary because x86's jprobe_return() would leave stale shadow on the stack, and was an oddity in that regard. Since then, jprobes were removed entirely, and as of commit: commit ("kprobes/x86: Remove jprobe implementation") ... there have been no callers of this function. Remove the declaration and the implementation. Signed-off-by:

Vincenzo Frascino <vincenzo.frascino@arm.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Reviewed-by:

Mark Rutland <mark.rutland@arm.com> Reviewed-by:

Andrey Konovalov <andreyknvl@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Link: http://lkml.kernel.org/r/20200706143505.23299-1-vincenzo.frascino@arm.com Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

include/linux/kasan.h

+0 −2

Original line number	Diff line number	Diff line
		@@ -38,7 +38,6 @@ extern void kasan_disable_current(void);
		void kasan_unpoison_shadow(const void *address, size_t size);

		void kasan_unpoison_task_stack(struct task_struct *task);
		void kasan_unpoison_stack_above_sp_to(const void *watermark);

		void kasan_alloc_pages(struct page *page, unsigned int order);
		void kasan_free_pages(struct page *page, unsigned int order);
		@@ -101,7 +100,6 @@ void kasan_restore_multi_shot(bool enabled);
		static inline void kasan_unpoison_shadow(const void *address, size_t size) {}

		static inline void kasan_unpoison_task_stack(struct task_struct *task) {}
		static inline void kasan_unpoison_stack_above_sp_to(const void *watermark) {}

		static inline void kasan_enable_current(void) {}
		static inline void kasan_disable_current(void) {}

mm/kasan/common.c

+0 −15

Original line number	Diff line number	Diff line
		@@ -180,21 +180,6 @@ asmlinkage void kasan_unpoison_task_stack_below(const void *watermark)
		kasan_unpoison_shadow(base, watermark - base);
		}

		/*
		* Clear all poison for the region between the current SP and a provided
		* watermark value, as is sometimes required prior to hand-crafted asm function
		* returns in the middle of functions.
		*/
		void kasan_unpoison_stack_above_sp_to(const void *watermark)
		{
		const void *sp = __builtin_frame_address(0);
		size_t size = watermark - sp;

		if (WARN_ON(sp > watermark))
		return;
		kasan_unpoison_shadow(sp, size);
		}

		void kasan_alloc_pages(struct page *page, unsigned int order)
		{
		u8 tag;

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