This is a note to let you know that I've just added the patch titled parisc: Fix crash with nr_cpus=1 option to the 6.1-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: parisc-fix-crash-with-nr_cpus-1-option.patch and it can be found in the queue-6.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From d3b3c637e4eb8d3bbe53e5692aee66add72f9851 Mon Sep 17 00:00:00 2001 From: Helge Deller <deller@xxxxxx> Date: Tue, 19 Sep 2023 15:26:35 +0200 Subject: parisc: Fix crash with nr_cpus=1 option From: Helge Deller <deller@xxxxxx> commit d3b3c637e4eb8d3bbe53e5692aee66add72f9851 upstream. John David Anglin reported that giving "nr_cpus=1" on the command line causes a crash, while "maxcpus=1" works. Reported-by: John David Anglin <dave.anglin@xxxxxxxx> Signed-off-by: Helge Deller <deller@xxxxxx> Cc: stable@xxxxxxxxxxxxxxx # v5.18+ Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/parisc/kernel/smp.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/arch/parisc/kernel/smp.c +++ b/arch/parisc/kernel/smp.c @@ -443,7 +443,9 @@ int __cpu_up(unsigned int cpu, struct ta if (cpu_online(cpu)) return 0; - if (num_online_cpus() < setup_max_cpus && smp_boot_one_cpu(cpu, tidle)) + if (num_online_cpus() < nr_cpu_ids && + num_online_cpus() < setup_max_cpus && + smp_boot_one_cpu(cpu, tidle)) return -EIO; return cpu_online(cpu) ? 0 : -EIO; Patches currently in stable-queue which might be from deller@xxxxxx are queue-6.1/parisc-fix-crash-with-nr_cpus-1-option.patch