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To: linux-kernel@vger.kernel.org
Cc: mingo@redhat.com, peterz@infradead.org, zhaolei@cn.fujitsu.com
From: "Pavel V. Panteleev" <panteleev_p@mcst.ru>
Subject: [sched/core] cpuacct_charge() problem
Message-ID: <5A046B8F.3060302@mcst.ru>
Date: Thu, 9 Nov 2017 17:51:59 +0300
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Hello!

task_pt_regs() always show on the user regs for user thread, even if 
it's working in kernel mode now. So, index calculation in 
cpuacct_charge() isn't correct and it's always  CPUACCT_STAT_USER for 
user thread. The time, spent in kernel mode for user task, will be lost:

int index = CPUACCT_STAT_SYSTEM;
struct pt_regs *regs = task_pt_regs(tsk);

if (regs && user_mode(regs))
     index = CPUACCT_STAT_USER;