From 248cc9993d1cc12b8e9ed716cc3fc09f6c3517dd Mon Sep 17 00:00:00 2001 From: Chengming Zhou Date: Sun, 20 Feb 2022 13:14:24 +0800 Subject: [PATCH] sched/cpuacct: Fix charge percpu cpuusage The cpuacct_account_field() is always called by the current task itself, so it's ok to use __this_cpu_add() to charge the tick time. But cpuacct_charge() maybe called by update_curr() in load_balance() on a random CPU, different from the CPU on which the task is running. So __this_cpu_add() will charge that cputime to a random incorrect CPU. Fixes: 73e6aafd9ea8 ("sched/cpuacct: Simplify the cpuacct code") Reported-by: Minye Zhu Signed-off-by: Chengming Zhou Signed-off-by: Peter Zijlstra (Intel) Acked-by: Tejun Heo Link: https://lore.kernel.org/r/20220220051426.5274-1-zhouchengming@bytedance.com --- kernel/sched/cpuacct.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c index 3d06c5e4220d..307800586ac8 100644 --- a/kernel/sched/cpuacct.c +++ b/kernel/sched/cpuacct.c @@ -334,12 +334,13 @@ static struct cftype files[] = { */ void cpuacct_charge(struct task_struct *tsk, u64 cputime) { + unsigned int cpu = task_cpu(tsk); struct cpuacct *ca; rcu_read_lock(); for (ca = task_ca(tsk); ca; ca = parent_ca(ca)) - __this_cpu_add(*ca->cpuusage, cputime); + *per_cpu_ptr(ca->cpuusage, cpu) += cputime; rcu_read_unlock(); }