Fix: handle negative clock offset
[lttng-modules.git] / lttng-events.c
index c49174ddc0966e0977b2a9d62a680b3f67ad85b7..bd6f44d977dba95e36c769f828b60e4fb9502c1f 100644 (file)
@@ -270,6 +270,48 @@ end:
        return ret;
 }
 
+int lttng_session_metadata_regenerate(struct lttng_session *session)
+{
+       int ret = 0;
+       struct lttng_channel *chan;
+       struct lttng_event *event;
+       struct lttng_metadata_cache *cache = session->metadata_cache;
+       struct lttng_metadata_stream *stream;
+
+       mutex_lock(&sessions_mutex);
+       if (!session->active) {
+               ret = -EBUSY;
+               goto end;
+       }
+
+       mutex_lock(&cache->lock);
+       memset(cache->data, 0, cache->cache_alloc);
+       cache->metadata_written = 0;
+       cache->version++;
+       list_for_each_entry(stream, &session->metadata_cache->metadata_stream, list) {
+               stream->metadata_out = 0;
+               stream->metadata_in = 0;
+       }
+       mutex_unlock(&cache->lock);
+
+       session->metadata_dumped = 0;
+       list_for_each_entry(chan, &session->chan, list) {
+               chan->metadata_dumped = 0;
+       }
+
+       list_for_each_entry(event, &session->events, list) {
+               event->metadata_dumped = 0;
+       }
+
+       ret = _lttng_session_metadata_statedump(session);
+
+end:
+       mutex_unlock(&sessions_mutex);
+       return ret;
+}
+
+
+
 int lttng_channel_enable(struct lttng_channel *channel)
 {
        int ret = 0;
@@ -329,8 +371,23 @@ int lttng_event_enable(struct lttng_event *event)
                ret = -EEXIST;
                goto end;
        }
-       ACCESS_ONCE(event->enabled) = 1;
-       lttng_session_sync_enablers(event->chan->session);
+       switch (event->instrumentation) {
+       case LTTNG_KERNEL_TRACEPOINT:
+       case LTTNG_KERNEL_SYSCALL:
+               ret = -EINVAL;
+               break;
+       case LTTNG_KERNEL_KPROBE:
+       case LTTNG_KERNEL_FUNCTION:
+       case LTTNG_KERNEL_NOOP:
+               ACCESS_ONCE(event->enabled) = 1;
+               break;
+       case LTTNG_KERNEL_KRETPROBE:
+               ret = lttng_kretprobes_event_enable_state(event, 1);
+               break;
+       default:
+               WARN_ON_ONCE(1);
+               ret = -EINVAL;
+       }
 end:
        mutex_unlock(&sessions_mutex);
        return ret;
@@ -349,8 +406,23 @@ int lttng_event_disable(struct lttng_event *event)
                ret = -EEXIST;
                goto end;
        }
-       ACCESS_ONCE(event->enabled) = 0;
-       lttng_session_sync_enablers(event->chan->session);
+       switch (event->instrumentation) {
+       case LTTNG_KERNEL_TRACEPOINT:
+       case LTTNG_KERNEL_SYSCALL:
+               ret = -EINVAL;
+               break;
+       case LTTNG_KERNEL_KPROBE:
+       case LTTNG_KERNEL_FUNCTION:
+       case LTTNG_KERNEL_NOOP:
+               ACCESS_ONCE(event->enabled) = 0;
+               break;
+       case LTTNG_KERNEL_KRETPROBE:
+               ret = lttng_kretprobes_event_enable_state(event, 0);
+               break;
+       default:
+               WARN_ON_ONCE(1);
+               ret = -EINVAL;
+       }
 end:
        mutex_unlock(&sessions_mutex);
        return ret;
@@ -538,7 +610,11 @@ struct lttng_event *_lttng_event_create(struct lttng_channel *chan,
                smp_wmb();
                break;
        case LTTNG_KERNEL_KPROBE:
-               event->enabled = 1;
+               /*
+                * Needs to be explicitly enabled after creation, since
+                * we may want to apply filters.
+                */
+               event->enabled = 0;
                event->registered = 1;
                /*
                 * Populate lttng_event structure before event
@@ -562,7 +638,11 @@ struct lttng_event *_lttng_event_create(struct lttng_channel *chan,
                struct lttng_event *event_return;
 
                /* kretprobe defines 2 events */
-               event->enabled = 1;
+               /*
+                * Needs to be explicitly enabled after creation, since
+                * we may want to apply filters.
+                */
+               event->enabled = 0;
                event->registered = 1;
                event_return =
                        kmem_cache_zalloc(event_cache, GFP_KERNEL);
@@ -573,7 +653,7 @@ struct lttng_event *_lttng_event_create(struct lttng_channel *chan,
                event_return->chan = chan;
                event_return->filter = filter;
                event_return->id = chan->free_event_id++;
-               event_return->enabled = 1;
+               event_return->enabled = 0;
                event_return->registered = 1;
                event_return->instrumentation = itype;
                /*
@@ -608,7 +688,11 @@ struct lttng_event *_lttng_event_create(struct lttng_channel *chan,
                break;
        }
        case LTTNG_KERNEL_FUNCTION:
-               event->enabled = 1;
+               /*
+                * Needs to be explicitly enabled after creation, since
+                * we may want to apply filters.
+                */
+               event->enabled = 0;
                event->registered = 1;
                /*
                 * Populate lttng_event structure before event
@@ -626,7 +710,11 @@ struct lttng_event *_lttng_event_create(struct lttng_channel *chan,
                break;
        case LTTNG_KERNEL_NOOP:
        case LTTNG_KERNEL_SYSCALL:
-               event->enabled = 1;
+               /*
+                * Needs to be explicitly enabled after creation, since
+                * we may want to apply filters.
+                */
+               event->enabled = 0;
                event->registered = 0;
                event->desc = event_desc;
                if (!event->desc) {
@@ -997,17 +1085,22 @@ int lttng_session_list_tracker_pids(struct lttng_session *session)
                ret = PTR_ERR(tracker_pids_list_file);
                goto file_error;
        }
+       if (atomic_long_add_unless(&session->file->f_count,
+               1, INT_MAX) == INT_MAX) {
+               goto refcount_error;
+       }
        ret = lttng_tracker_pids_list_fops.open(NULL, tracker_pids_list_file);
        if (ret < 0)
                goto open_error;
        m = tracker_pids_list_file->private_data;
        m->private = session;
        fd_install(file_fd, tracker_pids_list_file);
-       atomic_long_inc(&session->file->f_count);
 
        return file_fd;
 
 open_error:
+       atomic_long_dec(&session->file->f_count);
+refcount_error:
        fput(tracker_pids_list_file);
 file_error:
        put_unused_fd(file_fd);
@@ -1471,6 +1564,10 @@ int lttng_metadata_output_channel(struct lttng_metadata_stream *stream,
        if (stream->metadata_in != stream->metadata_out)
                goto end;
 
+       /* Metadata regenerated, change the version. */
+       if (stream->metadata_cache->version != stream->version)
+               stream->version = stream->metadata_cache->version;
+
        len = stream->metadata_cache->metadata_written -
                stream->metadata_in;
        if (!len)
@@ -1603,6 +1700,14 @@ int _lttng_field_statedump(struct lttng_session *session,
                const struct lttng_basic_type *elem_type;
 
                elem_type = &field->type.u.array.elem_type;
+               if (field->type.u.array.elem_alignment) {
+                       ret = lttng_metadata_printf(session,
+                       "               struct { } align(%u) _%s_padding;\n",
+                                       field->type.u.array.elem_alignment * CHAR_BIT,
+                                       field->name);
+                       if (ret)
+                               return ret;
+               }
                ret = lttng_metadata_printf(session,
                        "               integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s[%u];\n",
                        elem_type->u.basic.integer.size,
@@ -1649,6 +1754,14 @@ int _lttng_field_statedump(struct lttng_session *session,
                if (ret)
                        return ret;
 
+               if (field->type.u.sequence.elem_alignment) {
+                       ret = lttng_metadata_printf(session,
+                       "               struct { } align(%u) _%s_padding;\n",
+                                       field->type.u.sequence.elem_alignment * CHAR_BIT,
+                                       field->name);
+                       if (ret)
+                               return ret;
+               }
                ret = lttng_metadata_printf(session,
                        "               integer { size = %u; align = %u; signed = %u; encoding = %s; base = %u;%s } _%s[ __%s_length ];\n",
                        elem_type->u.basic.integer.size,
@@ -1910,11 +2023,15 @@ int _lttng_event_header_declare(struct lttng_session *session)
  * taken at start of trace.
  * Yes, this is only an approximation. Yes, we can (and will) do better
  * in future versions.
+ * Return 0 if offset is negative. It may happen if the system sets
+ * the REALTIME clock to 0 after boot.
  */
 static
 uint64_t measure_clock_offset(void)
 {
-       uint64_t offset, monotonic[2], realtime;
+       uint64_t monotonic_avg, monotonic[2], realtime;
+       uint64_t tcf = trace_clock_freq();
+       int64_t offset;
        struct timespec rts = { 0, 0 };
        unsigned long flags;
 
@@ -1925,10 +2042,19 @@ uint64_t measure_clock_offset(void)
        monotonic[1] = trace_clock_read64();
        local_irq_restore(flags);
 
-       offset = (monotonic[0] + monotonic[1]) >> 1;
-       realtime = (uint64_t) rts.tv_sec * NSEC_PER_SEC;
-       realtime += rts.tv_nsec;
-       offset = realtime - offset;
+       monotonic_avg = (monotonic[0] + monotonic[1]) >> 1;
+       realtime = (uint64_t) rts.tv_sec * tcf;
+       if (tcf == NSEC_PER_SEC) {
+               realtime += rts.tv_nsec;
+       } else {
+               uint64_t n = rts.tv_nsec * tcf;
+
+               do_div(n, NSEC_PER_SEC);
+               realtime += n;
+       }
+       offset = (int64_t) realtime - monotonic_avg;
+       if (offset < 0)
+               return 0;
        return offset;
 }
 
@@ -2021,8 +2147,8 @@ int _lttng_session_metadata_statedump(struct lttng_session *session)
 
        ret = lttng_metadata_printf(session,
                "clock {\n"
-               "       name = %s;\n",
-               "monotonic"
+               "       name = \"%s\";\n",
+               trace_clock_name()
                );
        if (ret)
                goto end;
@@ -2037,11 +2163,12 @@ int _lttng_session_metadata_statedump(struct lttng_session *session)
        }
 
        ret = lttng_metadata_printf(session,
-               "       description = \"Monotonic Clock\";\n"
+               "       description = \"%s\";\n"
                "       freq = %llu; /* Frequency, in Hz */\n"
                "       /* clock value offset from Epoch is: offset * (1/freq) */\n"
                "       offset = %llu;\n"
                "};\n\n",
+               trace_clock_description(),
                (unsigned long long) trace_clock_freq(),
                (unsigned long long) measure_clock_offset()
                );
@@ -2051,20 +2178,23 @@ int _lttng_session_metadata_statedump(struct lttng_session *session)
        ret = lttng_metadata_printf(session,
                "typealias integer {\n"
                "       size = 27; align = 1; signed = false;\n"
-               "       map = clock.monotonic.value;\n"
+               "       map = clock.%s.value;\n"
                "} := uint27_clock_monotonic_t;\n"
                "\n"
                "typealias integer {\n"
                "       size = 32; align = %u; signed = false;\n"
-               "       map = clock.monotonic.value;\n"
+               "       map = clock.%s.value;\n"
                "} := uint32_clock_monotonic_t;\n"
                "\n"
                "typealias integer {\n"
                "       size = 64; align = %u; signed = false;\n"
-               "       map = clock.monotonic.value;\n"
+               "       map = clock.%s.value;\n"
                "} := uint64_clock_monotonic_t;\n\n",
+               trace_clock_name(),
                lttng_alignof(uint32_t) * CHAR_BIT,
-               lttng_alignof(uint64_t) * CHAR_BIT
+               trace_clock_name(),
+               lttng_alignof(uint64_t) * CHAR_BIT,
+               trace_clock_name()
                );
        if (ret)
                goto end;
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