diff options
| author | Catalin Marinas <[email protected]> | 2022-05-17 10:35:32 +0100 |
|---|---|---|
| committer | Will Deacon <[email protected]> | 2022-05-17 14:29:51 +0100 |
| commit | 1d0cb4c8864addc362bae98e8ffa5500c87e1227 (patch) | |
| tree | a86bef28c0094d659065a86755b5b14fe433fa24 | |
| parent | eb3d8ea3e1f03f4b0b72d8f5ed9eb7c3165862e8 (diff) | |
arm64: mte: Ensure the cleared tags are visible before setting the PTE
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 <[email protected]>
Fixes: 34bfeea4a9e9 ("arm64: mte: Clear the tags when a page is mapped in user-space with PROT_MTE")
Cc: <[email protected]> # 5.10.x
Reported-by: Vladimir Murzin <[email protected]>
Cc: Will Deacon <[email protected]>
Reviewed-by: Steven Price <[email protected]>
Tested-by: Vladimir Murzin <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Will Deacon <[email protected]>
| -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 78b3e0f8e997..d502703e8373 100644 --- a/arch/arm64/kernel/mte.c +++ b/arch/arm64/kernel/mte.c @@ -76,6 +76,9 @@ void mte_sync_tags(pte_t old_pte, pte_t pte) mte_sync_page_tags(page, old_pte, check_swap, pte_is_tagged); } + + /* ensure the tags are visible before the PTE is set */ + smp_wmb(); } int memcmp_pages(struct page *page1, struct page *page2) |