Re: [PATCH v3 07/11] perf: Add breakpoint information to siginfo on SIGTRAP

[Peter Zijlstra]

One last try, I'll leave it alone now, I promise :-)

--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -778,6 +778,9 @@ struct perf_event {
        void *security;
 #endif
        struct list_head                sb_list;
+
+       unsigned long                   si_uattr;
+       unsigned long                   si_data;
 #endif /* CONFIG_PERF_EVENTS */
 };
 
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -5652,13 +5652,17 @@ static long _perf_ioctl(struct perf_even
                return perf_event_query_prog_array(event, (void __user *)arg);
 
        case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
+               struct perf_event_attr __user *uattr;
                struct perf_event_attr new_attr;
-               int err = perf_copy_attr((struct perf_event_attr __user *)arg,
-                                        &new_attr);
+               int err;
 
+               uattr = (struct perf_event_attr __user *)arg;
+               err = perf_copy_attr(uattr, &new_attr);
                if (err)
                        return err;
 
+               event->si_uattr = (unsigned long)uattr;
+
                return perf_event_modify_attr(event,  &new_attr);
        }
        default:
@@ -6399,7 +6403,12 @@ static void perf_sigtrap(struct perf_eve
        clear_siginfo(&info);
        info.si_signo = SIGTRAP;
        info.si_code = TRAP_PERF;
-       info.si_errno = event->attr.type;
+       info.si_addr = (void *)event->si_data;
+
+       info.si_perf = event->si_uattr;
+       if (event->parent)
+               info.si_perf = event->parent->si_uattr;
+
        force_sig_info(&info);
 }
 
@@ -6414,8 +6423,8 @@ static void perf_pending_event_disable(s
                WRITE_ONCE(event->pending_disable, -1);
 
                if (event->attr.sigtrap) {
-                       atomic_set(&event->event_limit, 1); /* rearm event */
                        perf_sigtrap(event);
+                       atomic_set_release(&event->event_limit, 1); /* rearm 
event */
                        return;
                }
 
@@ -9121,6 +9130,7 @@ static int __perf_event_overflow(struct
        if (events && atomic_dec_and_test(&event->event_limit)) {
                ret = 1;
                event->pending_kill = POLL_HUP;
+               event->si_data = data->addr;
 
                perf_event_disable_inatomic(event);
        }
@@ -12011,6 +12021,8 @@ SYSCALL_DEFINE5(perf_event_open,
                goto err_task;
        }
 
+       event->si_uattr = (unsigned long)attr_uptr;
+
        if (is_sampling_event(event)) {
                if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
                        err = -EOPNOTSUPP;