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| author | Catalin Marinas <catalin.marinas@arm.com> | 2022-05-17 12:35:32 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-05-25 10:17:56 +0300 |
| commit | 6013ef5f51e0861a904b74a694e621bb451fe7ae (patch) | |
| tree | 08588ab7d371cba98b2636a3796d4f129439262c | |
| parent | a817f78ed69bba10d724587dab84a164dac05900 (diff) | |
| download | linux-6013ef5f51e0861a904b74a694e621bb451fe7ae.tar.xz | |
arm64: mte: Ensure the cleared tags are visible before setting the PTE
commit 1d0cb4c8864addc362bae98e8ffa5500c87e1227 upstream.
As an optimisation, only pages mapped with PROT_MTE in user space have
the MTE tags zeroed. This is done lazily at the set_pte_at() time via
mte_sync_tags(). However, this function is missing a barrier and another
CPU may see the PTE updated before the zeroed tags are visible. Add an
smp_wmb() barrier if the mapping is Normal Tagged.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Fixes: 34bfeea4a9e9 ("arm64: mte: Clear the tags when a page is mapped in user-space with PROT_MTE")
Cc: <stable@vger.kernel.org> # 5.10.x
Reported-by: Vladimir Murzin <vladimir.murzin@arm.com>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Steven Price <steven.price@arm.com>
Tested-by: Vladimir Murzin <vladimir.murzin@arm.com>
Link: https://lore.kernel.org/r/20220517093532.127095-1-catalin.marinas@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/arm64/kernel/mte.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c index 7a66a7d9c1ff..4a069f85bd91 100644 --- a/arch/arm64/kernel/mte.c +++ b/arch/arm64/kernel/mte.c @@ -45,6 +45,9 @@ void mte_sync_tags(pte_t *ptep, pte_t pte) if (!test_and_set_bit(PG_mte_tagged, &page->flags)) mte_sync_page_tags(page, ptep, check_swap); } + + /* ensure the tags are visible before the PTE is set */ + smp_wmb(); } int memcmp_pages(struct page *page1, struct page *page2) |