Re: [PATCH v2] tracing: Add test for user space strings when filtering on string pointers

[Sven Schnelle]

Steven Rostedt <rostedt@xxxxxxxxxxx> writes:

> On Thu, 13 Jan 2022 16:51:15 -0500
> Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
>
>> We could add something later. As it is currently the merge window, and this
>> is a real bug, I'm going to just leave it as is, and we can work to fix the
>> other archs later. I need to get a pull request ready by tomorrow.
>
> Actually I got this working, and looks like a reasonable answer to the
> problem. It basically requires that the user specify that the pointer
> points into user space for the kernel to read it.
>
> Thus instead of:
>
>   echo 'filename ~ "trace"' > events/syscalls/sys_enter_openat/filter
>
> They must now do:
>
>   echo 'filename.ustring ~ "trace"' > events/syscalls/sys_enter_openat/filter
>
> I updated the documentation to reflect this.

Looks good and works on s390, feel free to add my tested-by:

Tested-by: Sven Schnelle <svens@xxxxxxxxxxxxx>

Thanks!