| From | andrey.konovalov@linux ... | Subject | [PATCH v2 08/34] kasan: only apply __GFP_ZEROTAGS when memory is zeroed | Date | Mon, 6 Dec 2021 22:43:45 +0100 |
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From: Andrey Konovalov <andreyknvl@google.com>
__GFP_ZEROTAGS should only be effective if memory is being zeroed. Currently, hardware tag-based KASAN violates this requirement.
Fix by including an initialization check along with checking for __GFP_ZEROTAGS.
Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Alexander Potapenko <glider@google.com> --- mm/kasan/hw_tags.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c index 0b8225add2e4..c643740b8599 100644 --- a/mm/kasan/hw_tags.c +++ b/mm/kasan/hw_tags.c @@ -199,11 +199,12 @@ void kasan_alloc_pages(struct page *page, unsigned int order, gfp_t flags) * 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 (flags & __GFP_ZEROTAGS) { + if (init_tags) { int i; for (i = 0; i != 1 << order; ++i) -- 2.25.1
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