[PATCH AUTOSEL 4.14 08/30] s390/cpuinfo: fix wrong output when CPU0 is offline

Sasha Levin
2020-04-15T12:10:03Z

From: Alexander Gordeev <agordeev@linux.ibm.com>

[ Upstream commit 872f27103874a73783aeff2aac2b41a489f67d7c ]

/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 <agordeev@linux.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
[heiko.carstens@de.ibm.com: shortened commit message]
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/s390/kernel/processor.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/s390/kernel/processor.c b/arch/s390/kernel/processor.c
index 6fe2e1875058b..675d4be0c2b77 100644
--- a/arch/s390/kernel/processor.c
+++ b/arch/s390/kernel/processor.c
@@ -157,8 +157,9 @@ static void show_cpu_mhz(struct seq_file *m, unsigned long n)
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;
@@ -171,6 +172,8 @@ 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;
}

--
2.20.1