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]>

0 files changed, 0 insertions, 0 deletions