On Tue, Feb 23, 2021 at 4:10 PM 'Marco Elver' via kasan-dev <[email protected]> wrote: > > > Encode information from breakpoint attributes into siginfo_t, which > > > helps disambiguate which breakpoint fired. > > > > > > Note, providing the event fd may be unreliable, since the event may have > > > been modified (via PERF_EVENT_IOC_MODIFY_ATTRIBUTES) between the event > > > triggering and the signal being delivered to user space. > > > > > > Signed-off-by: Marco Elver <[email protected]> > > > --- > > > kernel/events/core.c | 11 +++++++++++ > > > 1 file changed, 11 insertions(+) > > > > > > diff --git a/kernel/events/core.c b/kernel/events/core.c > > > index 8718763045fd..d7908322d796 100644 > > > --- a/kernel/events/core.c > > > +++ b/kernel/events/core.c > > > @@ -6296,6 +6296,17 @@ static void perf_sigtrap(struct perf_event *event) > > > info.si_signo = SIGTRAP; > > > info.si_code = TRAP_PERF; > > > info.si_errno = event->attr.type; > > > + > > > + switch (event->attr.type) { > > > + case PERF_TYPE_BREAKPOINT: > > > + info.si_addr = (void *)(unsigned long)event->attr.bp_addr; > > > + info.si_perf = (event->attr.bp_len << 16) | > > > (u64)event->attr.bp_type; > > > + break; > > > + default: > > > + /* No additional info set. */ > > > > Should we prohibit using attr.sigtrap for !PERF_TYPE_BREAKPOINT if we > > don't know what info to pass yet? > > I don't think it's necessary. This way, by default we get support for > other perf events. If user space observes si_perf==0, then there's no > information available. That would require that any event type that > sets si_perf in future, must ensure that it sets si_perf!=0. > > I can add a comment to document the requirement here (and user space > facing documentation should get a copy of how the info is encoded, > too). > > Alternatively, we could set si_errno to 0 if no info is available, at > the cost of losing the type information for events not explicitly > listed here. > > What do you prefer?
Ah, I see. Let's wait for the opinions of other people. There are a number of options for how to approach this. > > > + break; > > > + } > > > + > > > force_sig_info(&info); > > > } > > > > > > -- > > > 2.30.0.617.g56c4b15f3c-goog > > > > > -- > You received this message because you are subscribed to the Google Groups > "kasan-dev" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/kasan-dev/CANpmjNP1wQvG0SNPP2L9QO%3Dnatf0XU8HXj-r2_-U4QZxtr-dVA%40mail.gmail.com.
