diff mbox series

[v10,12/19] arm64: acpi: Harden get_cpu_for_acpi_id() against missing CPU entry

Message ID 20240529133446.28446-13-Jonathan.Cameron@huawei.com
State New
Headers show
Series ACPI/arm64: add support for virtual cpu hotplug | expand

Commit Message

Jonathan Cameron May 29, 2024, 1:34 p.m. UTC 
In a review discussion of the changes to support vCPU hotplug where
a check was added on the GICC being enabled if was online, it was
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.

Reviewed-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

---
V10: Fix description above (duplicated word).
     Picked up Gavin's tag.
---
 arch/arm64/include/asm/acpi.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
diff mbox series

Patch

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;