From: Muchun Song <songmuchun@bytedance.com>
To: peterz@infradead.org, tglx@linutronix.de, mingo@kernel.org,
bigeasy@linutronix.de, namit@vmware.com
Cc: linux-kernel@vger.kernel.org, Muchun Song <songmuchun@bytedance.com>
Subject: [PATCH v2] smp: Fix a potential usage of stale nr_cpus
Date: Sat, 18 Jul 2020 14:11:44 +0800 [thread overview]
Message-ID: <20200718061144.56095-1-songmuchun@bytedance.com> (raw)
When the cmdline of "nr_cpus" is not valid, the @nr_cpu_ids is assigned
a stale value. The nr_cpus is only valid when get_option() return 1. So
check the return value to prevent this.
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
---
changelog in v2:
1) Rework the commit log.
2) Rework the return value check.
kernel/smp.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/smp.c b/kernel/smp.c
index a5a66fc28f4e..0bc260158047 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -772,8 +772,8 @@ static int __init nrcpus(char *str)
{
int nr_cpus;
- get_option(&str, &nr_cpus);
- if (nr_cpus > 0 && nr_cpus < nr_cpu_ids)
+ if ((get_option(&str, &nr_cpus) == 1) &&
+ nr_cpus > 0 && nr_cpus < nr_cpu_ids)
nr_cpu_ids = nr_cpus;
return 0;
--
2.11.0
next reply other threads:[~2020-07-18 6:12 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-18 6:11 Muchun Song [this message]
2020-07-19 12:09 ` Thomas Gleixner
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