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| author | Huacai Chen <chenhuacai@loongson.cn> | 2024-06-18 11:13:36 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2024-06-23 21:04:14 +0300 |
| commit | 6ef8eb5125722c241fd60d7b0c872d5c2e5dd4ca (patch) | |
| tree | b3ecd3a1ac8a167ff3b1aaebc8082b3c6e3ef313 /kernel | |
| parent | 932d8476399f622aa0767a4a0a9e78e5341dc0e1 (diff) | |
| download | linux-6ef8eb5125722c241fd60d7b0c872d5c2e5dd4ca.tar.xz | |
cpu: Fix broken cmdline "nosmp" and "maxcpus=0"
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
Diffstat (limited to 'kernel')
| -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 74cfdb66a9bd..3d2bf1d50a0c 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -1859,6 +1859,9 @@ static inline bool cpuhp_bringup_cpus_parallel(unsigned int ncpus) { return fals void __init bringup_nonboot_cpus(unsigned int max_cpus) { + if (!max_cpus) + return; + /* Try parallel bringup optimization if enabled */ if (cpuhp_bringup_cpus_parallel(max_cpus)) return; |