Given that smp_call_function_single() can deadlock when interrupts are disabled, abort the SMP call if irqs_disabled(). This scenario is currently not possible given the function's uses, but safeguard this for potential future uses.
Signed-off-by: Ionela Voinescu <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: Will Deacon <[email protected]> --- arch/arm64/kernel/topology.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c index 3a083a9a8ef2..e387188741f2 100644 --- a/arch/arm64/kernel/topology.c +++ b/arch/arm64/kernel/topology.c @@ -343,7 +343,11 @@ static void cpu_read_constcnt(void *val) static inline int counters_read_on_cpu(int cpu, smp_call_func_t func, u64 *val) { - if (!cpu_has_amu_feat(cpu)) + /* + * Abort call on counterless CPU or when interrupts are + * disabled - can lead to deadlock in smp sync call. + */ + if (!cpu_has_amu_feat(cpu) || unlikely(irqs_disabled())) return -EOPNOTSUPP; smp_call_function_single(cpu, func, val, 1); -- 2.17.1
