From: Catalin Marinas <catalin.marinas@arm.com> To: Andrey Ryabinin <ryabinin.a.a@gmail.com>, Andrey Konovalov <andreyknvl@gmail.com> Cc: Will Deacon <will@kernel.org>, Vincenzo Frascino <vincenzo.frascino@arm.com>, Peter Collingbourne <pcc@google.com>, kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH 1/3] mm: kasan: Ensure the tags are visible before the tag in page->flags Date: Tue, 17 May 2022 19:09:43 +0100 [thread overview] Message-ID: <20220517180945.756303-2-catalin.marinas@arm.com> (raw) In-Reply-To: <20220517180945.756303-1-catalin.marinas@arm.com> __kasan_unpoison_pages() colours the memory with a random tag and stores it in page->flags in order to re-create the tagged pointer via page_to_virt() later. When the tag from the page->flags is read, ensure that the in-memory tags are already visible by re-ordering the page_kasan_tag_set() after kasan_unpoison(). The former already has barriers in place through try_cmpxchg(). On the reader side, the order is ensured by the address dependency between page->flags and the memory access. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> --- mm/kasan/common.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/kasan/common.c b/mm/kasan/common.c index d9079ec11f31..f6b8dc4f354b 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -108,9 +108,10 @@ void __kasan_unpoison_pages(struct page *page, unsigned int order, bool init) return; tag = kasan_random_tag(); + kasan_unpoison(set_tag(page_address(page), tag), + PAGE_SIZE << order, init); for (i = 0; i < (1 << order); i++) page_kasan_tag_set(page + i, tag); - kasan_unpoison(page_address(page), PAGE_SIZE << order, init); } void __kasan_poison_pages(struct page *page, unsigned int order, bool init)
WARNING: multiple messages have this Message-ID (diff)
From: Catalin Marinas <catalin.marinas@arm.com> To: Andrey Ryabinin <ryabinin.a.a@gmail.com>, Andrey Konovalov <andreyknvl@gmail.com> Cc: Will Deacon <will@kernel.org>, Vincenzo Frascino <vincenzo.frascino@arm.com>, Peter Collingbourne <pcc@google.com>, kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH 1/3] mm: kasan: Ensure the tags are visible before the tag in page->flags Date: Tue, 17 May 2022 19:09:43 +0100 [thread overview] Message-ID: <20220517180945.756303-2-catalin.marinas@arm.com> (raw) In-Reply-To: <20220517180945.756303-1-catalin.marinas@arm.com> __kasan_unpoison_pages() colours the memory with a random tag and stores it in page->flags in order to re-create the tagged pointer via page_to_virt() later. When the tag from the page->flags is read, ensure that the in-memory tags are already visible by re-ordering the page_kasan_tag_set() after kasan_unpoison(). The former already has barriers in place through try_cmpxchg(). On the reader side, the order is ensured by the address dependency between page->flags and the memory access. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> --- mm/kasan/common.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/kasan/common.c b/mm/kasan/common.c index d9079ec11f31..f6b8dc4f354b 100644 --- a/mm/kasan/common.c +++ b/mm/kasan/common.c @@ -108,9 +108,10 @@ void __kasan_unpoison_pages(struct page *page, unsigned int order, bool init) return; tag = kasan_random_tag(); + kasan_unpoison(set_tag(page_address(page), tag), + PAGE_SIZE << order, init); for (i = 0; i < (1 << order); i++) page_kasan_tag_set(page + i, tag); - kasan_unpoison(page_address(page), PAGE_SIZE << order, init); } void __kasan_poison_pages(struct page *page, unsigned int order, bool init) _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2022-05-17 18:09 UTC|newest] Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-05-17 18:09 [PATCH 0/3] kasan: Fix ordering between MTE tag colouring and page->flags Catalin Marinas 2022-05-17 18:09 ` Catalin Marinas 2022-05-17 18:09 ` Catalin Marinas [this message] 2022-05-17 18:09 ` [PATCH 1/3] mm: kasan: Ensure the tags are visible before the tag in page->flags Catalin Marinas 2022-05-21 22:14 ` Andrey Konovalov 2022-05-21 22:14 ` Andrey Konovalov 2022-05-17 18:09 ` [PATCH 2/3] mm: kasan: Reset the tag on pages intended for user Catalin Marinas 2022-05-17 18:09 ` Catalin Marinas 2022-05-21 22:15 ` Andrey Konovalov 2022-05-21 22:15 ` Andrey Konovalov 2022-05-17 18:09 ` [PATCH 3/3] arm64: kasan: Revert "arm64: mte: reset the page tag in page->flags" Catalin Marinas 2022-05-17 18:09 ` Catalin Marinas 2022-05-21 22:16 ` Andrey Konovalov 2022-05-21 22:16 ` Andrey Konovalov 2022-05-19 21:45 ` [PATCH 0/3] kasan: Fix ordering between MTE tag colouring and page->flags Andrey Konovalov 2022-05-19 21:45 ` Andrey Konovalov 2022-05-20 13:01 ` Catalin Marinas 2022-05-20 13:01 ` Catalin Marinas 2022-05-21 22:20 ` Andrey Konovalov 2022-05-21 22:20 ` Andrey Konovalov 2022-05-25 15:45 ` Catalin Marinas 2022-05-25 15:45 ` Catalin Marinas 2022-05-25 17:41 ` Andrey Konovalov 2022-05-25 17:41 ` Andrey Konovalov 2022-05-26 12:24 ` Catalin Marinas 2022-05-26 12:24 ` Catalin Marinas 2022-05-31 17:16 ` Andrey Konovalov 2022-05-31 17:16 ` Andrey Konovalov 2022-06-09 18:32 ` Catalin Marinas 2022-06-09 18:32 ` Catalin Marinas 2022-06-09 18:40 ` Andrey Konovalov 2022-06-09 18:40 ` Andrey Konovalov
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