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?
Thank you, On Thu, 30 Oct 2025 12:26:55 +0900 "Masami Hiramatsu (Google)" <[email protected]> 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/[email protected]/ > > 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) <[email protected]> -- Masami Hiramatsu (Google) <[email protected]>
