This is a note to let you know that I've just added the patch titled
powerpc/smp: Adjust nr_cpu_ids to cover all threads of a core
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-adjust-nr_cpu_ids-to-cover-all-threads-o.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 8213fc299b681cad1f69ea7152ca6ed73d1b1832
Author: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Date: Thu Feb 15 00:14:04 2024 +1100
powerpc/smp: Adjust nr_cpu_ids to cover all threads of a core
[ Upstream commit 5580e96dad5a439d561d9648ffcbccb739c2a120 ]
If nr_cpu_ids is too low to include at least all the threads of a single
core adjust nr_cpu_ids upwards. This avoids triggering odd bugs in code
that assumes all threads of a core are available.
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://msgid.link/20231229120107.2281153-1-mpe@xxxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 0b5878c3125b1..58e80076bed5c 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -375,6 +375,12 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
if (IS_ENABLED(CONFIG_PPC64))
boot_cpu_hwid = be32_to_cpu(intserv[found_thread]);
+ if (nr_cpu_ids % nthreads != 0) {
+ set_nr_cpu_ids(ALIGN(nr_cpu_ids, nthreads));
+ pr_warn("nr_cpu_ids was not a multiple of threads_per_core, adjusted to %d\n",
+ nr_cpu_ids);
+ }
+
/*
* PAPR defines "logical" PVR values for cpus that
* meet various levels of the architecture:
