Fix: baddr_statedump deadlock with JUL tracing
[lttng-ust.git] / liblttng-ust / lttng-events.c
index 00babd0ebd293807abc7d9d07df4030173978897..9380e9ceb688b9b46df58122d7cc3a47c14421b3 100644 (file)
@@ -45,7 +45,7 @@
 
 #include <usterr-signal-safe.h>
 #include <helper.h>
-#include <ust-ctl.h>
+#include <lttng/ust-ctl.h>
 #include <ust-comm.h>
 #include "error.h"
 #include "compat.h"
@@ -78,7 +78,6 @@ void ust_unlock(void)
 static CDS_LIST_HEAD(sessions);
 
 static void _lttng_event_destroy(struct lttng_event *event);
-static int _lttng_event_unregister(struct lttng_event *event);
 
 static
 void lttng_session_lazy_sync_enablers(struct lttng_session *session);
@@ -170,17 +169,57 @@ void _lttng_channel_unmap(struct lttng_channel *lttng_chan)
        channel_destroy(chan, handle, 0);
 }
 
+static
+void register_event(struct lttng_event *event)
+{
+       int ret;
+       const struct lttng_event_desc *desc;
+
+       assert(event->registered == 0);
+       desc = event->desc;
+       ret = __tracepoint_probe_register(desc->name,
+                       desc->probe_callback,
+                       event, desc->signature);
+       WARN_ON_ONCE(ret);
+       if (!ret)
+               event->registered = 1;
+}
+
+static
+void unregister_event(struct lttng_event *event)
+{
+       int ret;
+       const struct lttng_event_desc *desc;
+
+       assert(event->registered == 1);
+       desc = event->desc;
+       ret = __tracepoint_probe_unregister(desc->name,
+                       desc->probe_callback,
+                       event);
+       WARN_ON_ONCE(ret);
+       if (!ret)
+               event->registered = 0;
+}
+
+/*
+ * Only used internally at session destruction.
+ */
+static
+void _lttng_event_unregister(struct lttng_event *event)
+{
+       if (event->registered)
+               unregister_event(event);
+}
+
 void lttng_session_destroy(struct lttng_session *session)
 {
        struct lttng_channel *chan, *tmpchan;
        struct lttng_event *event, *tmpevent;
        struct lttng_enabler *enabler, *tmpenabler;
-       int ret;
 
        CMM_ACCESS_ONCE(session->active) = 0;
        cds_list_for_each_entry(event, &session->events_head, node) {
-               ret = _lttng_event_unregister(event);
-               WARN_ON(ret);
+               _lttng_event_unregister(event);
        }
        synchronize_trace();    /* Wait for in-flight events to complete */
        cds_list_for_each_entry_safe(enabler, tmpenabler,
@@ -210,6 +249,8 @@ int lttng_session_enable(struct lttng_session *session)
        if (notify_socket < 0)
                return notify_socket;
 
+       /* Set transient enabler state to "enabled" */
+       session->tstate = 1;
        /* We need to sync enablers with session before activation. */
        lttng_session_sync_enablers(session);
 
@@ -219,8 +260,9 @@ int lttng_session_enable(struct lttng_session *session)
         */
        cds_list_for_each_entry(chan, &session->chan_head, node) {
                const struct lttng_ctx *ctx;
-               const struct lttng_event_field *fields = NULL;
+               const struct lttng_ctx_field *fields = NULL;
                size_t nr_fields = 0;
+               uint32_t chan_id;
 
                /* don't change it if session stop/restart */
                if (chan->header_type)
@@ -228,23 +270,32 @@ int lttng_session_enable(struct lttng_session *session)
                ctx = chan->ctx;
                if (ctx) {
                        nr_fields = ctx->nr_fields;
-                       fields = &ctx->fields->event_field;
+                       fields = ctx->fields;
                }
                ret = ustcomm_register_channel(notify_socket,
                        session->objd,
                        chan->objd,
                        nr_fields,
                        fields,
-                       &chan->id,
+                       &chan_id,
                        &chan->header_type);
                if (ret) {
                        DBG("Error (%d) registering channel to sessiond", ret);
                        return ret;
                }
+               if (chan_id != chan->id) {
+                       DBG("Error: channel registration id (%u) does not match id assigned at creation (%u)",
+                               chan_id, chan->id);
+                       return -EINVAL;
+               }
        }
 
+       /* Set atomically the state to "active" */
        CMM_ACCESS_ONCE(session->active) = 1;
        CMM_ACCESS_ONCE(session->been_active) = 1;
+
+       session->statedump_pending = 1;
+       lttng_ust_sockinfo_session_enabled(session->owner);
 end:
        return ret;
 }
@@ -257,29 +308,48 @@ int lttng_session_disable(struct lttng_session *session)
                ret = -EBUSY;
                goto end;
        }
+       /* Set atomically the state to "inactive" */
        CMM_ACCESS_ONCE(session->active) = 0;
+
+       /* Set transient enabler state to "disabled" */
+       session->tstate = 0;
+       lttng_session_sync_enablers(session);
 end:
        return ret;
 }
 
 int lttng_channel_enable(struct lttng_channel *channel)
 {
-       int old;
+       int ret = 0;
 
-       old = uatomic_xchg(&channel->enabled, 1);
-       if (old)
-               return -EEXIST;
-       return 0;
+       if (channel->enabled) {
+               ret = -EBUSY;
+               goto end;
+       }
+       /* Set transient enabler state to "enabled" */
+       channel->tstate = 1;
+       lttng_session_sync_enablers(channel->session);
+       /* Set atomically the state to "enabled" */
+       CMM_ACCESS_ONCE(channel->enabled) = 1;
+end:
+       return ret;
 }
 
 int lttng_channel_disable(struct lttng_channel *channel)
 {
-       int old;
+       int ret = 0;
 
-       old = uatomic_xchg(&channel->enabled, 0);
-       if (!old)
-               return -EEXIST;
-       return 0;
+       if (!channel->enabled) {
+               ret = -EBUSY;
+               goto end;
+       }
+       /* Set atomically the state to "disabled" */
+       CMM_ACCESS_ONCE(channel->enabled) = 0;
+       /* Set transient enabler state to "enabled" */
+       channel->tstate = 0;
+       lttng_session_sync_enablers(channel->session);
+end:
+       return ret;
 }
 
 /*
@@ -304,9 +374,9 @@ int lttng_event_create(const struct lttng_event_desc *desc,
        head = &chan->session->events_ht.table[hash & (LTTNG_UST_EVENT_HT_SIZE - 1)];
        cds_hlist_for_each_entry(event, node, head, hlist) {
                assert(event->desc);
-               if (!strncmp(event->desc->name,
-                               desc->name,
-                               LTTNG_UST_SYM_NAME_LEN - 1)) {
+               if (!strncmp(event->desc->name, desc->name,
+                                       LTTNG_UST_SYM_NAME_LEN - 1)
+                               && chan == event->chan) {
                        ret = -EEXIST;
                        goto exist;
                }
@@ -328,7 +398,9 @@ int lttng_event_create(const struct lttng_event_desc *desc,
        }
        event->chan = chan;
 
-       event->enabled = 1;
+       /* Event will be enabled by enabler sync. */
+       event->enabled = 0;
+       event->registered = 0;
        CDS_INIT_LIST_HEAD(&event->bytecode_runtime_head);
        CDS_INIT_LIST_HEAD(&event->enablers_ref_head);
        event->desc = desc;
@@ -360,17 +432,10 @@ int lttng_event_create(const struct lttng_event_desc *desc,
 
        /* Populate lttng_event structure before tracepoint registration. */
        cmm_smp_wmb();
-       ret = __tracepoint_probe_register(event_name,
-                       desc->probe_callback,
-                       event, desc->signature);
-       if (ret)
-               goto tracepoint_register_error;
-
        cds_list_add(&event->node, &chan->session->events_head);
        cds_hlist_add_head(&event->hlist, head);
        return 0;
 
-tracepoint_register_error:
 sessiond_register_error:
        free(event);
 cache_error:
@@ -384,7 +449,7 @@ int lttng_desc_match_wildcard_enabler(const struct lttng_event_desc *desc,
                struct lttng_enabler *enabler)
 {
        int loglevel = 0;
-       unsigned int has_loglevel;
+       unsigned int has_loglevel = 0;
 
        assert(enabler->type == LTTNG_ENABLER_WILDCARD);
        /* Compare excluding final '*' */
@@ -429,6 +494,31 @@ static
 int lttng_desc_match_enabler(const struct lttng_event_desc *desc,
                struct lttng_enabler *enabler)
 {
+       struct lttng_ust_excluder_node *excluder;
+
+       /* If event matches with an excluder, return 'does not match' */
+       cds_list_for_each_entry(excluder, &enabler->excluder_head, node) {
+               int count;
+
+               for (count = 0; count < excluder->excluder.count; count++) {
+                       int found, len;
+                       char *excluder_name;
+
+                       excluder_name = (char *) (excluder->excluder.names)
+                                       + count * LTTNG_UST_SYM_NAME_LEN;
+                       len = strnlen(excluder_name, LTTNG_UST_SYM_NAME_LEN);
+                       if (len > 0 && excluder_name[len - 1] == '*') {
+                               found = !strncmp(desc->name, excluder_name,
+                                               len - 1);
+                       } else {
+                               found = !strncmp(desc->name, excluder_name,
+                                               LTTNG_UST_SYM_NAME_LEN - 1);
+                       }
+                       if (found) {
+                               return 0;
+                       }
+               }
+       }
        switch (enabler->type) {
        case LTTNG_ENABLER_WILDCARD:
                return lttng_desc_match_wildcard_enabler(desc, enabler);
@@ -443,7 +533,11 @@ static
 int lttng_event_match_enabler(struct lttng_event *event,
                struct lttng_enabler *enabler)
 {
-       return lttng_desc_match_enabler(event->desc, enabler);
+       if (lttng_desc_match_enabler(event->desc, enabler)
+                       && event->chan == enabler->chan)
+               return 1;
+       else
+               return 0;
 }
 
 static
@@ -501,7 +595,8 @@ void lttng_create_event_if_missing(struct lttng_enabler *enabler)
                        hash = jhash(event_name, name_len, 0);
                        head = &session->events_ht.table[hash & (LTTNG_UST_EVENT_HT_SIZE - 1)];
                        cds_hlist_for_each_entry(event, node, head, hlist) {
-                               if (event->desc == desc)
+                               if (event->desc == desc
+                                               && event->chan == enabler->chan)
                                        found = 1;
                        }
                        if (found)
@@ -568,12 +663,9 @@ int lttng_enabler_ref_events(struct lttng_enabler *enabler)
 /*
  * Called at library load: connect the probe on all enablers matching
  * this event.
- * called with session mutex held.
- * TODO: currently, for each desc added, we iterate on all event desc
- * (inefficient). We should create specific code that only target the
- * added desc.
+ * Called with session mutex held.
  */
-int lttng_fix_pending_event_desc(const struct lttng_event_desc *desc)
+int lttng_fix_pending_events(void)
 {
        struct lttng_session *session;
 
@@ -584,13 +676,19 @@ int lttng_fix_pending_event_desc(const struct lttng_event_desc *desc)
 }
 
 /*
- * Only used internally at session destruction.
+ * Called after session enable: For each session, execute pending statedumps.
  */
-int _lttng_event_unregister(struct lttng_event *event)
+int lttng_handle_pending_statedumps(t_statedump_func_ptr statedump_func_ptr)
 {
-       return __tracepoint_probe_unregister(event->desc->name,
-                                         event->desc->probe_callback,
-                                         event);
+       struct lttng_session *session;
+
+       cds_list_for_each_entry(session, &sessions, node) {
+               if (session->statedump_pending) {
+                       session->statedump_pending = 0;
+                       statedump_func_ptr(session);
+               }
+       }
+       return 0;
 }
 
 /*
@@ -633,6 +731,7 @@ struct lttng_enabler *lttng_enabler_create(enum lttng_enabler_type type,
                return NULL;
        enabler->type = type;
        CDS_INIT_LIST_HEAD(&enabler->filter_bytecode_head);
+       CDS_INIT_LIST_HEAD(&enabler->excluder_head);
        memcpy(&enabler->event_param, event_param,
                sizeof(enabler->event_param));
        enabler->chan = chan;
@@ -666,6 +765,15 @@ int lttng_enabler_attach_bytecode(struct lttng_enabler *enabler,
        return 0;
 }
 
+int lttng_enabler_attach_exclusion(struct lttng_enabler *enabler,
+               struct lttng_ust_excluder_node *excluder)
+{
+       excluder->enabler = enabler;
+       cds_list_add_tail(&excluder->node, &enabler->excluder_head);
+       lttng_session_lazy_sync_enablers(enabler->chan->session);
+       return 0;
+}
+
 int lttng_attach_context(struct lttng_ust_context *context_param,
                struct lttng_ctx **ctx, struct lttng_session *session)
 {
@@ -686,6 +794,8 @@ int lttng_attach_context(struct lttng_ust_context *context_param,
                return lttng_add_vpid_to_ctx(ctx);
        case LTTNG_UST_CONTEXT_PROCNAME:
                return lttng_add_procname_to_ctx(ctx);
+       case LTTNG_UST_CONTEXT_IP:
+               return lttng_add_ip_to_ctx(ctx);
        default:
                return -EINVAL;
        }
@@ -711,6 +821,7 @@ static
 void lttng_enabler_destroy(struct lttng_enabler *enabler)
 {
        struct lttng_ust_filter_bytecode_node *filter_node, *tmp_filter_node;
+       struct lttng_ust_excluder_node *excluder_node, *tmp_excluder_node;
 
        /* Destroy filter bytecode */
        cds_list_for_each_entry_safe(filter_node, tmp_filter_node,
@@ -718,6 +829,12 @@ void lttng_enabler_destroy(struct lttng_enabler *enabler)
                free(filter_node);
        }
 
+       /* Destroy excluders */
+       cds_list_for_each_entry_safe(excluder_node, tmp_excluder_node,
+                       &enabler->excluder_head, node) {
+               free(excluder_node);
+       }
+
        /* Destroy contexts */
        lttng_destroy_context(enabler->ctx);
 
@@ -739,7 +856,8 @@ void lttng_session_sync_enablers(struct lttng_session *session)
                lttng_enabler_ref_events(enabler);
        /*
         * For each event, if at least one of its enablers is enabled,
-        * we enable the event, else we disable it.
+        * and its channel and session transient states are enabled, we
+        * enable the event, else we disable it.
         */
        cds_list_for_each_entry(event, &session->events_head, node) {
                struct lttng_enabler_ref *enabler_ref;
@@ -754,7 +872,25 @@ void lttng_session_sync_enablers(struct lttng_session *session)
                                break;
                        }
                }
-               event->enabled = enabled;
+               /*
+                * Enabled state is based on union of enablers, with
+                * intesection of session and channel transient enable
+                * states.
+                */
+               enabled = enabled && session->tstate && event->chan->tstate;
+
+               CMM_STORE_SHARED(event->enabled, enabled);
+               /*
+                * Sync tracepoint registration with event enabled
+                * state.
+                */
+               if (enabled) {
+                       if (!event->registered)
+                               register_event(event);
+               } else {
+                       if (event->registered)
+                               unregister_event(event);
+               }
 
                /* Check if has enablers without bytecode enabled */
                cds_list_for_each_entry(enabler_ref,
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