This is a note to let you know that I've just added the patch titled
powerpc/smp: Increase nr_cpu_ids to include the boot CPU
to the 6.8-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:
powerpc-smp-increase-nr_cpu_ids-to-include-the-boot-.patch
and it can be found in the queue-6.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 4084a96f508e1370ffe4a469cfa0123f6e785059
Author: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Date: Thu Feb 15 00:14:04 2024 +1100
powerpc/smp: Increase nr_cpu_ids to include the boot CPU
[ Upstream commit 777f81f0a9c780a6443bcf2c7785f0cc2e87c1ef ]
If nr_cpu_ids is too low to include the boot CPU adjust nr_cpu_ids
upward. Otherwise the kernel will BUG when trying to allocate a paca
for the boot CPU and fail to boot.
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://msgid.link/20231229120107.2281153-2-mpe@xxxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 58e80076bed5c..77364729a1b61 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -381,6 +381,12 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
nr_cpu_ids);
}
+ if (boot_cpuid >= nr_cpu_ids) {
+ set_nr_cpu_ids(min(CONFIG_NR_CPUS, ALIGN(boot_cpuid + 1, nthreads)));
+ pr_warn("Boot CPU %d >= nr_cpu_ids, adjusted nr_cpu_ids to %d\n",
+ boot_cpuid, nr_cpu_ids);
+ }
+
/*
* PAPR defines "logical" PVR values for cpus that
* meet various levels of the architecture:
