Commit f5f92020 authored by Muchun Song's avatar Muchun Song Committed by Xia Fukun
Browse files

sched/cpuacct: Fix charge cpuacct.usage_sys 

mainline inclusion
from mainline-v6.5-rc7
commit dbe93371
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8BN4B


CVE: NA

--------------------------------

The user_mode(task_pt_regs(tsk)) always return true for
user thread, and false for kernel thread. So it means that
the cpuacct.usage_sys is the time that kernel thread uses
not the time that thread uses in the kernel mode. We can
try get_irq_regs() first, if it is NULL, then we can fall
back to task_pt_regs().

Signed-off-by: default avatarMuchun Song <songmuchun@bytedance.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200420070453.76815-1-songmuchun@bytedance.com


Signed-off-by: default avatarXia Fukun <xiafukun@huawei.com>
parent 19ac6490

kernel/sched/cpuacct.c

+2 −1
Original line number Diff line number Diff line
@@ -5,6 +5,7 @@ 
 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh

 * (balbir@in.ibm.com).

 */

#include <asm/irq_regs.h>

#include "sched.h"



/* Time spent by the tasks of the CPU accounting group executing in ... */
@@ -339,7 +340,7 @@ void cpuacct_charge(struct task_struct *tsk, u64 cputime) 
{

	struct cpuacct *ca;

	int index = CPUACCT_STAT_SYSTEM;

	struct pt_regs *regs = task_pt_regs(tsk);

	struct pt_regs *regs = get_irq_regs() ? : task_pt_regs(tsk);



	if (regs && user_mode(regs))

		index = CPUACCT_STAT_USER;