# Re: \[PATCH\] trace: reenable preemption if we modify the ip

- From: Daniel Borkmann \<daniel@iogearbox.net\>
- Date: 2017-12-17 19:49:33 
- List: netdev
- Page: https://ratatoskr.run/netdev/2017/12/5160490
- Thread: https://ratatoskr.run/netdev/2017/12/5159976/t.md

```text
On 12/16/2017 03:42 AM, Josef Bacik wrote:
> From: Josef Bacik <redacted>
> 
> Things got moved around between the original bpf_override_return patches
> and the final version, and now the ftrace kprobe dispatcher assumes if
> you modified the ip that you also enabled preemption.  Make a comment of
> this and enable preemption, this fixes the lockdep splat that happened
> when using this feature.
> 
> Signed-off-by: Josef Bacik <redacted>

Applied to bpf-next with Fixes tag, thanks Josef.
```