# Re: \[PATCH v2 1/2\] unwind\_user/x86: Enable frame pointer unwinding on x86

- From: Steven Rostedt \<rostedt@kernel.org\>
- Date: 2025-09-23 12:21:06 
- List: linux-trace-kernel
- Page: https://ratatoskr.run/linux-trace-kernel/2025/09/3227974
- Thread: https://ratatoskr.run/linux-trace-kernel/2025/08/3189483/t.md

```text
On Tue, 23 Sep 2025 12:51:30 +0200
Peter Zijlstra [ref] wrote:

> Moo, and now you have me look at unwind/user.c:
> 
>         /* Make sure that the address is word aligned */
>         shift = sizeof(long) == 4 ? 2 : 3;
>         if (cfa & ((1 << shift) - 1))
>                 return -EINVAL;
> 
> Isn't that just:
> 
> 	if (cfa & (sizeof(long) - 1))
> 
> ?
> 
> Let me go add a patch to clean that up...

Sure, as long as it's commented.

Thanks,

-- Steve
```