From: Alexander Gordeev Date: Mon, 16 Mar 2020 12:39:55 +0100 Subject: s390/cpuinfo: fix wrong output when CPU0 is offline Git-commit: 872f27103874a73783aeff2aac2b41a489f67d7c Patch-mainline: v5.7-rc1 References: git-fixes /proc/cpuinfo should not print information about CPU 0 when it is offline. Fixes: 281eaa8cb67c ("s390/cpuinfo: simplify locking and skip offline cpus early") Signed-off-by: Alexander Gordeev Reviewed-by: Heiko Carstens [heiko.carstens@de.ibm.com: shortened commit message] Signed-off-by: Heiko Carstens Signed-off-by: Vasily Gorbik Acked-by: Petr Tesarik --- arch/s390/kernel/processor.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/arch/s390/kernel/processor.c +++ b/arch/s390/kernel/processor.c @@ -156,8 +156,9 @@ static void show_cpu_mhz(struct seq_file static int show_cpuinfo(struct seq_file *m, void *v) { unsigned long n = (unsigned long) v - 1; + unsigned long first = cpumask_first(cpu_online_mask); - if (!n) + if (n == first) show_cpu_summary(m, v); if (!machine_has_cpu_mhz) return 0; @@ -170,6 +171,8 @@ static inline void *c_update(loff_t *pos { if (*pos) *pos = cpumask_next(*pos - 1, cpu_online_mask); + else + *pos = cpumask_first(cpu_online_mask); return *pos < nr_cpu_ids ? (void *)*pos + 1 : NULL; }