[PATCH] sched/cpuacct: Check for NULL when using task_pt_regs()
Anton Blanchard
anton at samba.org
Wed Apr 13 18:17:38 AEST 2016
task_pt_regs() can return NULL for kernel threads, so add a check.
This fixes an oops at boot on ppc64.
Fixes: d740037fac70 ("sched/cpuacct: Split usage accounting into user_usage and sys_usage")
Signed-off-by: Anton Blanchard <anton at samba.org>
Reported-and-Tested-by: Srikar Dronamraju <srikar at linux.vnet.ibm.com>
---
diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c
index df947e0..41f85c4 100644
--- a/kernel/sched/cpuacct.c
+++ b/kernel/sched/cpuacct.c
@@ -316,12 +316,11 @@ static struct cftype files[] = {
void cpuacct_charge(struct task_struct *tsk, u64 cputime)
{
struct cpuacct *ca;
- int index;
+ int index = CPUACCT_USAGE_SYSTEM;
+ struct pt_regs *regs = task_pt_regs(tsk);
- if (user_mode(task_pt_regs(tsk)))
+ if (regs && user_mode(regs))
index = CPUACCT_USAGE_USER;
- else
- index = CPUACCT_USAGE_SYSTEM;
rcu_read_lock();
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