+ kasan-optimize-large-kmalloc-poisoning.patch added to -mm tree

* + kasan-optimize-large-kmalloc-poisoning.patch added to -mm tree
@ 2021-02-01 22:46 akpm
  0 siblings, 0 replies; 2+ messages in thread
From: akpm @ 2021-02-01 22:46 UTC (permalink / raw)
  To: andreyknvl, aryabinin, Branislav.Rankov, catalin.marinas,
	dvyukov, elver, eugenis, glider, kevin.brodsky, mm-commits, pcc,
	vincenzo.frascino, will.deacon


The patch titled
     Subject: kasan: optimize large kmalloc poisoning
has been added to the -mm tree.  Its filename is
     kasan-optimize-large-kmalloc-poisoning.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/kasan-optimize-large-kmalloc-poisoning.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/kasan-optimize-large-kmalloc-poisoning.patch

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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next and is updated
there every 3-4 working days

------------------------------------------------------
From: Andrey Konovalov <andreyknvl@google.com>
Subject: kasan: optimize large kmalloc poisoning

Similarly to kasan_kmalloc(), kasan_kmalloc_large() doesn't need to
unpoison the object as it as already unpoisoned by alloc_pages() (or by
ksize() for krealloc()).

This patch changes kasan_kmalloc_large() to only poison the redzone.

Link: https://lkml.kernel.org/r/8fdbf86842f4eaf2458ecd23d0844058dbc2c7a2.1612208222.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Marco Elver <elver@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/kasan/common.c |   20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

--- a/mm/kasan/common.c~kasan-optimize-large-kmalloc-poisoning
+++ a/mm/kasan/common.c
@@ -494,7 +494,6 @@ EXPORT_SYMBOL(__kasan_kmalloc);
 void * __must_check __kasan_kmalloc_large(const void *ptr, size_t size,
 						gfp_t flags)
 {
-	struct page *page;
 	unsigned long redzone_start;
 	unsigned long redzone_end;
 
@@ -504,12 +503,23 @@ void * __must_check __kasan_kmalloc_larg
 	if (unlikely(ptr == NULL))
 		return NULL;
 
-	page = virt_to_page(ptr);
+	/*
+	 * The object has already been unpoisoned by kasan_alloc_pages() for
+	 * alloc_pages() or by ksize() for krealloc().
+	 */
+
+	/*
+	 * The redzone has byte-level precision for the generic mode.
+	 * Partially poison the last object granule to cover the unaligned
+	 * part of the redzone.
+	 */
+	if (IS_ENABLED(CONFIG_KASAN_GENERIC))
+		kasan_poison_last_granule(ptr, size);
+
+	/* Poison the aligned part of the redzone. */
 	redzone_start = round_up((unsigned long)(ptr + size),
 				KASAN_GRANULE_SIZE);
-	redzone_end = (unsigned long)ptr + page_size(page);
-
-	kasan_unpoison(ptr, size);
+	redzone_end = (unsigned long)ptr + page_size(virt_to_page(ptr));
 	kasan_poison((void *)redzone_start, redzone_end - redzone_start,
 		     KASAN_PAGE_REDZONE);
 
_

Patches currently in -mm which might be from andreyknvl@google.com are

kasan-prefix-global-functions-with-kasan_.patch
kasan-clarify-hw_tags-impact-on-tbi.patch
kasan-clean-up-comments-in-tests.patch
kasan-add-macros-to-simplify-checking-test-constraints.patch
kasan-add-match-all-tag-tests.patch
kasan-arm64-allow-using-kunit-tests-with-hw_tags-mode.patch
kasan-rename-config_test_kasan_module.patch
kasan-add-compiler-barriers-to-kunit_expect_kasan_fail.patch
kasan-adapt-kmalloc_uaf2-test-to-hw_tags-mode.patch
kasan-fix-memory-corruption-in-kasan_bitops_tags-test.patch
kasan-move-_ret_ip_-to-inline-wrappers.patch
kasan-fix-bug-detection-via-ksize-for-hw_tags-mode.patch
kasan-add-proper-page-allocator-tests.patch
kasan-add-a-test-for-kmem_cache_alloc-free_bulk.patch
kasan-dont-run-tests-when-kasan-is-not-enabled.patch
kasan-mm-dont-save-alloc-stacks-twice.patch
kasan-mm-optimize-kmalloc-poisoning.patch
kasan-optimize-large-kmalloc-poisoning.patch
kasan-clean-up-setting-free-info-in-kasan_slab_free.patch
kasan-unify-large-kfree-checks.patch
kasan-rework-krealloc-tests.patch
kasan-mm-remove-krealloc-side-effect.patch
kasan-mm-optimize-krealloc-poisoning.patch
kasan-ensure-poisoning-size-alignment.patch
arm64-kasan-simplify-and-inline-mte-functions.patch
kasan-always-inline-hw_tags-helper-functions.patch
arm64-kasan-export-mte-symbols-for-kasan-tests.patch


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