Messages in this thread | | | From | Dmitry Vyukov <> | Date | Wed, 3 Feb 2021 13:50:51 +0100 | Subject | Re: Process-wide watchpoints |
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On Wed, Feb 3, 2021 at 1:49 PM Dmitry Vyukov <dvyukov@google.com> wrote: > > On Wed, Feb 3, 2021 at 1:29 PM Peter Zijlstra <peterz@infradead.org> wrote: > > > > On Mon, Feb 01, 2021 at 09:50:20AM +0100, Dmitry Vyukov wrote: > > > Or, alternatively would it be reasonable for perf to generate SIGTRAP > > > directly on watchpoint hit (like ptrace does)? That's what I am > > > ultimately trying to do by attaching a bpf program. > > > > Perf should be able to generate signals, The perf_event_open manpage > > lists two ways of trigering signals. The second way doesn't work for > > you, due to it not working on inherited counters, but would the first > > work? > > > > That is, set attr::wakeup_events and fcntl(F_SETSIG). > > The problem is that this sends a signal to the fd owner rather than > the thread that hit the breakpoint. At least that's what happened in > our tests. We would like to send a signal to the thread that hit the > breakpoint.
I think that signal also does not carry the address and other info typically present in SIGTRAP/SIGSEGV.
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