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

Ingo, Will, Ping?

I also found that Kyle made a change on this area recently.

Thank you,

On Thu, 30 Oct 2025 12:26:55 +0900
"Masami Hiramatsu (Google)" [off-list ref] wrote:

Hi,

Here are patches which fixes a wprobe bug reported by Mark Brown on
arm64[1]. The root cause was that the infinite watchpoint exception on
the same instruction, because arm64 watchpoint exception happens before
the memory access has done, it needs to configure a single-step after
calling overflow handler. It does that only for the default overflow
handlers, and not for custom overflow handler registered via
hw_breakpoint interface.

[1] https://lore.kernel.org/all/aPvwGhMBJqMKcC9D@finisterre.sirena.org.uk/ (local)

To fix this issue, this series introduces default_overflow_compatible
flag in the perf_event and use it for identifying default overflow
handlers instead of checking handler functions everytime[1/2], and
set it in wprobe[2/2].

Thank you,

---

Masami Hiramatsu (Google) (2):
      perf: Introduce default_overflow_compatible flag
      tracing: wprobe: Make wprobe_handler default overflow_handler compatible


 include/linux/perf_event.h  |    9 ++-------
 kernel/events/core.c        |    2 ++
 kernel/trace/trace_wprobe.c |    7 +++++++
 3 files changed, 11 insertions(+), 7 deletions(-)

--
Masami Hiramatsu (Google) [off-list ref]

-- 
Masami Hiramatsu (Google) [off-list ref]