4.15-stable review patch. If anyone has any objections, please let me know.
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From: James Morse james.morse@arm.com
Commit edf298cfce47 upstream.
this_cpu_has_cap() tests caps->desc not caps->matches, so it stops walking the list when it finds a 'silent' feature, instead of walking to the end of the list.
Prior to v4.6's 644c2ae198412 ("arm64: cpufeature: Test 'matches' pointer to find the end of the list") we always tested desc to find the end of a capability list. This was changed for dubious things like PAN_NOT_UAO. v4.7's e3661b128e53e ("arm64: Allow a capability to be checked on single CPU") added this_cpu_has_cap() using the old desc style test.
CC: Suzuki K Poulose suzuki.poulose@arm.com Reviewed-by: Suzuki K Poulose suzuki.poulose@arm.com Acked-by: Marc Zyngier marc.zyngier@arm.com Signed-off-by: James Morse james.morse@arm.com Signed-off-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Will Deacon will.deacon@arm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm64/kernel/cpufeature.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
--- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1173,9 +1173,8 @@ static bool __this_cpu_has_cap(const str if (WARN_ON(preemptible())) return false;
- for (caps = cap_array; caps->desc; caps++) + for (caps = cap_array; caps->matches; caps++) if (caps->capability == cap && - caps->matches && caps->matches(caps, SCOPE_LOCAL_CPU)) return true; return false;