arm64: smp: Prevent raw_smp_processor_id() recursion
Under CONFIG_DEBUG_PREEMPT=y, this_cpu_ptr() ends up calling back into
raw_smp_processor_id(), resulting in some hilariously catastrophic
infinite recursion. In the normal case, we have:
#define this_cpu_ptr(ptr) raw_cpu_ptr(ptr)
and everything is dandy. However for CONFIG_DEBUG_PREEMPT, this_cpu_ptr()
is defined in terms of my_cpu_offset, wherein the fun begins:
#define my_cpu_offset per_cpu_offset(smp_processor_id())
...
#define smp_processor_id() debug_smp_processor_id()
...
notrace unsigned int debug_smp_processor_id(void)
{
return check_preemption_disabled("smp_processor_id", "");
...
notrace static unsigned int check_preemption_disabled(const char *what1,
const char *what2)
{
int this_cpu = raw_smp_processor_id();
and bang. Use raw_cpu_ptr() directly to avoid that.
Fixes: 57c82954e77f ("arm64: make cpu number a percpu variable")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
1 file changed