Re: [PATCH v2 01/33] ftrace: Unpoison ftrace_regs in ftrace_ops_list_func()

[Steven Rostedt]

On Fri, 8 Dec 2023 15:16:10 +0100
Alexander Potapenko <glider@xxxxxxxxxx> wrote:

> On Tue, Nov 21, 2023 at 11:02 PM Ilya Leoshkevich <iii@xxxxxxxxxxxxx> wrote:
> >
> > Architectures use assembly code to initialize ftrace_regs and call
> > ftrace_ops_list_func(). Therefore, from the KMSAN's point of view,
> > ftrace_regs is poisoned on ftrace_ops_list_func entry(). This causes
> > KMSAN warnings when running the ftrace testsuite.  
> 
> I couldn't reproduce these warnings on x86, hope you really need this
> change on s390 :)

On x86, ftrace_regs sits on the stack. And IIUC, s390 doesn't have the same
concept of a "stack" as other architectures. Perhaps that's the reason s390
needs this?

-- Steve