4.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: James Morse <james.morse@xxxxxxx>
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@xxxxxxx>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
Acked-by: Marc Zyngier <marc.zyngier@xxxxxxx>
Signed-off-by: James Morse <james.morse@xxxxxxx>
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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;