On 5/1/24 00:24, Jonathan Cameron wrote:
In a review discussion of the changes to support vCPU hotplug where
a check was added on the GICC being enabled if was was online, it was
^^^^^^^
typo
noted that there is need to map back to the cpu and use that to index
into a cpumask. As such, a valid ID is needed.
If an MPIDR check fails in acpi_map_gic_cpu_interface() it is possible
for the entry in cpu_madt_gicc[cpu] == NULL. This function would
then cause a NULL pointer dereference. Whilst a path to trigger
this has not been established, harden this caller against the
possibility.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
---
v9: New patch in response to a question from Marc Zyngier.
Taking the easy way out - harden against a possible condition rather
than establishing it never happens!
---
arch/arm64/include/asm/acpi.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
With the typo corrected:
Reviewed-by: Gavin Shan <gshan@xxxxxxxxxx>
diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h
index bc9a6656fc0c..a407f9cd549e 100644
--- a/arch/arm64/include/asm/acpi.h
+++ b/arch/arm64/include/asm/acpi.h
@@ -124,7 +124,8 @@ static inline int get_cpu_for_acpi_id(u32 uid)
int cpu;
for (cpu = 0; cpu < nr_cpu_ids; cpu++)
- if (uid == get_acpi_id_for_cpu(cpu))
+ if (acpi_cpu_get_madt_gicc(cpu) &&
+ uid == get_acpi_id_for_cpu(cpu))
return cpu;
return -EINVAL;
