Messages in this thread Patch in this message | | | Date | Wed, 6 Apr 2016 21:59:50 +1000 | From | Anton Blanchard <> | Subject | [PATCH] sched/cpuacct: Check for NULL when using task_pt_regs() |
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Hi Peter,
> Ah, so sometihng like: > > struct pt_regs *regs = task_pt_regs(); > int index = CPUACCT_USAGE_SYSTEM; > > if (regs && user_mode(regs)) > index = CPUACCT_USAGE_USER; > > should work, right?
Looks good, and the patch below does fix the oops for me.
Anton --
task_pt_regs() can return NULL for kernel threads, so add a check. This fixes an oops at boot on ppc64.
Signed-off-by: Anton Blanchard <anton@samba.org> ---
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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