iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

cpu: Fix broken cmdline "nosmp" and "maxcpus=0"

Browse Source 
commit 6ef8eb5125722c241fd60d7b0c872d5c2e5dd4ca upstream.

After the rework of "Parallel CPU bringup", the cmdline "nosmp" and
"maxcpus=0" parameters are not working anymore. These parameters set
setup_max_cpus to zero and that's handed to bringup_nonboot_cpus().

The code there does a decrement before checking for zero, which brings it
into the negative space and brings up all CPUs.

Add a zero check at the beginning of the function to prevent this.

[ tglx: Massaged change log ]

Fixes: 18415f33e2ac4ab382 ("cpu/hotplug: Allow "parallel" bringup up to CPUHP_BP_KICK_AP_STATE")
Fixes: 06c6796e0304234da6 ("cpu/hotplug: Fix off by one in cpuhp_bringup_mask()")
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240618081336.3996825-1-chenhuacai@loongson.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Huacai Chen 2024-06-18 16:13:36 +08:00 committed by Greg Kroah-Hartman
parent b0a41715ed
commit 69787793e7
1 changed files with 3 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
kernel/cpu.c
View File

@ -1907,6 +1907,9 @@ static inline bool cpuhp_bringup_cpus_parallel(unsigned int ncpus) { return fals
void __init bringup_nonboot_cpus(unsigned int setup_max_cpus)
{
if (!setup_max_cpus)
return;
/* Try parallel bringup optimization if enabled */
if (cpuhp_bringup_cpus_parallel(setup_max_cpus))
return;