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 <zhuminye@bytedance.com>
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220220051426.5274-1-zhouchengming@bytedance.com

diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c
index 3d06c5e4220d4da54e93dc2d0791bfccc8afae21..307800586ac81e1bd973445e88412be4cef31905 100644 (file)
--- 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();
 }