From: Andrey Konovalov <andreyknvl@google.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Dmitry Vyukov <dvyukov@google.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Alexander Potapenko <glider@google.com>,
Marco Elver <elver@google.com>,
Peter Collingbourne <pcc@google.com>,
Evgenii Stepanov <eugenis@google.com>,
Branislav Rankov <Branislav.Rankov@arm.com>,
Kevin Brodsky <kevin.brodsky@arm.com>,
Christoph Hellwig <hch@infradead.org>,
kasan-dev@googlegroups.com, linux-arm-kernel@lists.infradead.org,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Andrey Konovalov <andreyknvl@google.com>
Subject: [PATCH] kasan, mm: fix crash with HW_TAGS and DEBUG_PAGEALLOC
Date: Fri, 26 Feb 2021 02:25:37 +0100 [thread overview]
Message-ID: <1aa83e48627978de8068d5e3314185f3a0d7a849.1614302398.git.andreyknvl@google.com> (raw)
Currently, kasan_free_nondeferred_pages()->kasan_free_pages() is called
after debug_pagealloc_unmap_pages(). This causes a crash when
debug_pagealloc is enabled, as HW_TAGS KASAN can't set tags on an
unmapped page.
This patch puts kasan_free_nondeferred_pages() before
debug_pagealloc_unmap_pages().
Besides fixing the crash, this also makes the annotation order consistent
with debug_pagealloc_map_pages() preceding kasan_alloc_pages().
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
mm/page_alloc.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index c89e7b107514..54bc237fd319 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1311,10 +1311,14 @@ static __always_inline bool free_pages_prepare(struct page *page,
*/
arch_free_page(page, order);
- debug_pagealloc_unmap_pages(page, 1 << order);
-
+ /*
+ * With hardware tag-based KASAN, memory tags must be set
+ * before unmapping the page with debug_pagealloc.
+ */
kasan_free_nondeferred_pages(page, order, fpi_flags);
+ debug_pagealloc_unmap_pages(page, 1 << order);
+
return true;
}
--
2.30.1.766.gb4fecdf3b7-goog
next reply other threads:[~2021-02-26 1:26 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-26 1:25 Andrey Konovalov [this message]
2021-03-03 23:23 ` [PATCH] kasan, mm: fix crash with HW_TAGS and DEBUG_PAGEALLOC Andrew Morton
2021-03-05 15:43 ` Andrey Konovalov
2021-03-05 17:04 ` Andrey Konovalov
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