From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, andreyknvl@gmail.com,
linux-mm@kvack.org, mm-commits@vger.kernel.org, pcc@google.com,
peterz@infradead.org, stable@vger.kernel.org,
torvalds@linux-foundation.org
Subject: [patch 08/12] mm, kasan: use compare-exchange operation to set KASAN page tag
Date: Sat, 29 Jan 2022 13:41:14 -0800 [thread overview]
Message-ID: <20220129214114.kH5sHZ6C3%akpm@linux-foundation.org> (raw)
In-Reply-To: <20220129134026.8ccf701012f26eb2c2c269c9@linux-foundation.org>
From: Peter Collingbourne <pcc@google.com>
Subject: mm, kasan: use compare-exchange operation to set KASAN page tag
It has been reported that the tag setting operation on newly-allocated
pages can cause the page flags to be corrupted when performed concurrently
with other flag updates as a result of the use of non-atomic operations.
Fix the problem by using a compare-exchange loop to update the tag.
Link: https://lkml.kernel.org/r/20220120020148.1632253-1-pcc@google.com
Link: https://linux-review.googlesource.com/id/I456b24a2b9067d93968d43b4bb3351c0cec63101
Fixes: 2813b9c02962 ("kasan, mm, arm64: tag non slab memory allocated via pagealloc")
Signed-off-by: Peter Collingbourne <pcc@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
include/linux/mm.h | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
--- a/include/linux/mm.h~mm-use-compare-exchange-operation-to-set-kasan-page-tag
+++ a/include/linux/mm.h
@@ -1506,11 +1506,18 @@ static inline u8 page_kasan_tag(const st
static inline void page_kasan_tag_set(struct page *page, u8 tag)
{
- if (kasan_enabled()) {
- tag ^= 0xff;
- page->flags &= ~(KASAN_TAG_MASK << KASAN_TAG_PGSHIFT);
- page->flags |= (tag & KASAN_TAG_MASK) << KASAN_TAG_PGSHIFT;
- }
+ unsigned long old_flags, flags;
+
+ if (!kasan_enabled())
+ return;
+
+ tag ^= 0xff;
+ old_flags = READ_ONCE(page->flags);
+ do {
+ flags = old_flags;
+ flags &= ~(KASAN_TAG_MASK << KASAN_TAG_PGSHIFT);
+ flags |= (tag & KASAN_TAG_MASK) << KASAN_TAG_PGSHIFT;
+ } while (unlikely(!try_cmpxchg(&page->flags, &old_flags, flags)));
}
static inline void page_kasan_tag_reset(struct page *page)
_
next prev parent reply other threads:[~2022-01-29 21:41 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-29 21:40 incoming Andrew Morton
2022-01-29 21:40 ` [patch 01/12] include/linux/sysctl.h: fix register_sysctl_mount_point() return type Andrew Morton
2022-01-29 21:40 ` [patch 02/12] binfmt_misc: fix crash when load/unload module Andrew Morton
2022-01-29 21:40 ` [patch 03/12] ia64: make IA64_MCA_RECOVERY bool instead of tristate Andrew Morton
2022-01-29 21:41 ` [patch 04/12] memory-failure: fetch compound_head after pgmap_pfn_valid() Andrew Morton
2022-01-29 21:41 ` [patch 05/12] mm: page->mapping folio->mapping should have the same offset Andrew Morton
2022-01-29 21:41 ` [patch 06/12] tools/testing/scatterlist: add missing defines Andrew Morton
2022-01-29 21:41 ` [patch 07/12] kasan: test: fix compatibility with FORTIFY_SOURCE Andrew Morton
2022-01-29 21:41 ` Andrew Morton [this message]
2022-01-29 21:41 ` [patch 09/12] psi: fix "no previous prototype" warnings when CONFIG_CGROUPS=n Andrew Morton
2022-01-29 21:41 ` [patch 10/12] psi: fix "defined but not used" warnings when CONFIG_PROC_FS=n Andrew Morton
2022-01-29 21:41 ` [patch 11/12] jbd2: export jbd2_journal_[grab|put]_journal_head Andrew Morton
2022-01-29 21:41 ` [patch 12/12] ocfs2: fix a deadlock when commit trans Andrew Morton
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