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FROMGIT: kasan, page_alloc: merge kasan_alloc_pages into post_alloc_hook

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Currently, the code responsible for initializing and poisoning memory in
post_alloc_hook() is scattered across two locations: kasan_alloc_pages()
hook for HW_TAGS KASAN and post_alloc_hook() itself.  This is confusing.

This and a few following patches combine the code from these two
locations.  Along the way, these patches do a step-by-step restructure the
many performed checks to make them easier to follow.

Replace the only caller of kasan_alloc_pages() with its implementation.

As kasan_has_integrated_init() is only true when CONFIG_KASAN_HW_TAGS is
enabled, moving the code does no functional changes.

Also move init and init_tags variables definitions out of
kasan_has_integrated_init() clause in post_alloc_hook(), as they have the
same values regardless of what the if condition evaluates to.

This patch is not useful by itself but makes the simplifications in the
following patches easier to follow.

Link: https://lkml.kernel.org/r/5ac7e0b30f5cbb177ec363ddd7878a3141289592.1643047180.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Acked-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
(cherry picked from commit 2a10554bf7e83f0613511f6781afe03cebab5a6c
 git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git akpm)
Bug: 217222520
Change-Id: Iafd536232d6f9996887f9e7e47b22f6d65e6c28a
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
This commit is contained in:
Andrey Konovalov
2022-01-27 16:25:48 +11:00
parent eedf930064
commit 00ab827157
4 changed files with 16 additions and 37 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
include/linux/kasan.h
View File

@@ -94,8 +94,6 @@ static inline bool kasan_hw_tags_enabled(void)
return kasan_enabled();
}
void kasan_alloc_pages(struct page *page, unsigned int order, gfp_t flags);
#else /* CONFIG_KASAN_HW_TAGS */
static inline bool kasan_enabled(void)
@@ -108,13 +106,6 @@ static inline bool kasan_hw_tags_enabled(void)
return false;
}
static __always_inline void kasan_alloc_pages(struct page *page,
unsigned int order, gfp_t flags)
{
/* Only available for integrated init. */
BUILD_BUG();
}
#endif /* CONFIG_KASAN_HW_TAGS */
static inline bool kasan_has_integrated_init(void)

2
mm/kasan/common.c
View File

@@ -535,7 +535,7 @@ void * __must_check __kasan_kmalloc_large(const void *ptr, size_t size,
return NULL;
/*
* The object has already been unpoisoned by kasan_alloc_pages() for
* The object has already been unpoisoned by kasan_unpoison_pages() for
* alloc_pages() or by kasan_krealloc() for krealloc().
*/

22
mm/kasan/hw_tags.c
View File

@@ -192,28 +192,6 @@ void __init kasan_init_hw_tags(void)
kasan_stack_collection_enabled() ? "on" : "off");
}
void kasan_alloc_pages(struct page *page, unsigned int order, gfp_t flags)
{
/*
* This condition should match the one in post_alloc_hook() in
* page_alloc.c.
*/
bool init = !want_init_on_free() && want_init_on_alloc(flags);
bool init_tags = init && (flags & __GFP_ZEROTAGS);
if (flags & __GFP_SKIP_KASAN_POISON)
SetPageSkipKASanPoison(page);
if (init_tags) {
int i;
for (i = 0; i != 1 << order; ++i)
tag_clear_highpage(page + i);
} else {
kasan_unpoison_pages(page, order, init);
}
}
#if IS_ENABLED(CONFIG_KASAN_KUNIT_TEST)
void kasan_enable_tagging_sync(void)

20
mm/page_alloc.c
View File

@@ -2391,6 +2391,9 @@ static bool check_new_pages(struct page *page, unsigned int order)
inline void post_alloc_hook(struct page *page, unsigned int order,
gfp_t gfp_flags)
{
bool init = !want_init_on_free() && want_init_on_alloc(gfp_flags);
bool init_tags = init && (gfp_flags & __GFP_ZEROTAGS);
set_page_private(page, 0);
set_page_refcounted(page);
@@ -2406,15 +2409,22 @@ inline void post_alloc_hook(struct page *page, unsigned int order,
/*
* As memory initialization might be integrated into KASAN,
* kasan_alloc_pages and kernel_init_free_pages must be
* KASAN unpoisoning and memory initializion code must be
* kept together to avoid discrepancies in behavior.
*/
if (kasan_has_integrated_init()) {
kasan_alloc_pages(page, order, gfp_flags);
} else {
bool init = !want_init_on_free() && want_init_on_alloc(gfp_flags);
bool init_tags = init && (gfp_flags & __GFP_ZEROTAGS);
if (gfp_flags & __GFP_SKIP_KASAN_POISON)
SetPageSkipKASanPoison(page);
if (init_tags) {
int i;
for (i = 0; i != 1 << order; ++i)
tag_clear_highpage(page + i);
} else {
kasan_unpoison_pages(page, order, init);
}
} else {
kasan_unpoison_pages(page, order, init);
if (init_tags) {