Re: [PATCH 0/2] tracing/wprobe: Fix to avoid inifinite watchpoint exception on arm64

[Google]

On Fri, 14 Nov 2025 16:17:06 +0000
Will Deacon <will@xxxxxxxxxx> wrote:

> On Tue, Nov 04, 2025 at 10:37:35PM +0900, Masami Hiramatsu wrote:
> > Gently ping.
> > 
> > There is a bugfix (or strange behavior) on arm64 hw breakpoint but
> > to fix it cleanly, it should change the perf itself (but I'm not
> > sure why arm64 changes the behavior only for the default overflow
> > handlers.) Anyone knows it?
> 
> It's because GDB expects to handle the stepping itself when using the
> ptrace interface (with a custom overflow handler to deliver SIGTRAP).

Hmm, would you mean GDB for user program?
If so, it expects hw breakpoint is used by:
 - user-space ptrace (for GDB)
 - kernel-space perf (must be default overflow handler)

And not expects to be used by 

 - kernel-space custom overflow handler

This series is to handle the third use case.

Thank you,

-- 
Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>