Re: [PATCH v11 04/11] tracing: wprobe: Add watchpoint probe event based on hardware breakpoint
Peter Zijlstra <[email protected]> Thu, 6 Aug 2026 09:17:37 +0200
| Newsgroups | org.kernel.vger.linux-trace-kernel,org.kernel.vger.linux-doc,org.kernel.vger.linux-kernel,org.kernel.vger.linux-perf-users |
|---|---|
| Message-ID | <[email protected]> |
On Wed, Aug 05, 2026 at 09:06:29PM -0400, Steven Rostedt wrote: > On Wed, 5 Aug 2026 21:39:09 +0200 > Peter Zijlstra <[email protected]> wrote: > > > > > This seems limited to kernel addresses only? Should not also userspace > > > > addresses be supported? > > > > > > Hmm, how would that work? The address is global for all tasks, so if you > > > add a user space address, what task would that be for? The one writing the > > > probe? > > > > Schedule the watchpoint along with the task of course. Given there is > > breakpoint/perf integration this should be trivial. > > I meant, what task is it attached to? Usually the way a probe works is to > create the probe and then enable it. > > # cd /sys/kernel/tracing > # echo 'w:my_jiffies w@jiffies:8 value=+0($addr)' >> dynamic_events > # echo 1 > events/wprobes/my_jiffies/enable > > If the address is in user space, which task would that address be for? > > What would the API look like? Should we add a pid to that for a specific task? Same as uprobes?