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| author | Huacai Chen <chenhuacai@loongson.cn> | 2024-06-18 16:13:36 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-07-11 12:49:14 +0200 |
| commit | 69787793e7f0673465c89714d1522fde978bbfa8 (patch) | |
| tree | d06676ff5724f7a4e58701ee14c9ff290d06c71b /kernel/cpu.c | |
| parent | b0a41715ed23a8cc738327504c656cad745b57da (diff) | |
| download | linux-69787793e7f0673465c89714d1522fde978bbfa8.tar.gz linux-69787793e7f0673465c89714d1522fde978bbfa8.tar.bz2 linux-69787793e7f0673465c89714d1522fde978bbfa8.zip | |
cpu: Fix broken cmdline "nosmp" and "maxcpus=0"
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>
Diffstat (limited to 'kernel/cpu.c')
| -rw-r--r-- | kernel/cpu.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c index 7ef4bc17453c..874bfb952e6e 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -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; |