This is a note to let you know that I've just added the patch titled
arm64: acpi: Harden get_cpu_for_acpi_id() against missing CPU entry
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm64-acpi-harden-get_cpu_for_acpi_id-against-missin.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 56e68fd0af2a34acf6517b9d4d820442c614f7b7
Author: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Date: Wed May 29 14:34:39 2024 +0100
arm64: acpi: Harden get_cpu_for_acpi_id() against missing CPU entry
[ Upstream commit 2488444274c70038eb6b686cba5f1ce48ebb9cdd ]
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@xxxxxxxxxx>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240529133446.28446-13-Jonathan.Cameron@xxxxxxxxxx
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@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;
