# Re: powerpc/perf: add missing put\_cpu\_var in power\_pmu\_event\_init

- From: Michael Ellerman \<mpe@ellerman.id.au\>
- Date: 2015-03-25 05:25:12 
- List: linuxppc-dev
- Page: https://ratatoskr.run/linuxppc-dev/2015/03/4458691
- Thread: https://ratatoskr.run/linuxppc-dev/2015/03/4457721/t.md

```text
On Tue, 2015-24-03 at 12:33:22 UTC, Jan Stancek wrote:
> One path in power_pmu_event_init() calls get_cpu_var(), but is
> missing matching call to put_cpu_var(), which causes preemption
> imbalance and crash in user-space:
> 
>   Page fault in user mode with in_atomic() = 1 mm = c000001fefa5a280
>   NIP = 3fff9bf2cae0  MSR = 900000014280f032
>   Oops: Weird page fault, sig: 11 [#23]

<snip>

Thanks. But I don't see this. I guess you have CONFIG_PREEMPT enabled?

cheers
```