X-Git-Url: https://git.lttng.org/?a=blobdiff_plain;f=src%2Fbin%2Flttng-sessiond%2Fust-app.c;h=dfc4599be858315b3a2b25956b0daa49e9d24bd2;hb=094d1690f11fb6aeddac6acd71ba50a3c4e4e9b1;hp=9bd4e69a2e031be166da7cac0e81edba38d44147;hpb=b34cbebfc8e60a678782bcffdf4ff8fc12de037e;p=lttng-tools.git diff --git a/src/bin/lttng-sessiond/ust-app.c b/src/bin/lttng-sessiond/ust-app.c index 9bd4e69a2..dfc4599be 100644 --- a/src/bin/lttng-sessiond/ust-app.c +++ b/src/bin/lttng-sessiond/ust-app.c @@ -305,6 +305,23 @@ void delete_ust_app_stream(int sock, struct ust_app_stream *stream) free(stream); } +/* + * We need to execute ht_destroy outside of RCU read-side critical + * section, so we postpone its execution using call_rcu. It is simpler + * than to change the semantic of the many callers of + * delete_ust_app_channel(). + */ +static +void delete_ust_app_channel_rcu(struct rcu_head *head) +{ + struct ust_app_channel *ua_chan = + caa_container_of(head, struct ust_app_channel, rcu_head); + + lttng_ht_destroy(ua_chan->ctx); + lttng_ht_destroy(ua_chan->events); + free(ua_chan); +} + /* * Delete ust app channel safely. RCU read lock must be held before calling * this function. @@ -336,7 +353,6 @@ void delete_ust_app_channel(int sock, struct ust_app_channel *ua_chan, assert(!ret); delete_ust_app_ctx(sock, ua_ctx); } - lttng_ht_destroy(ua_chan->ctx); /* Wipe events */ cds_lfht_for_each_entry(ua_chan->events->ht, &iter.iter, ua_event, @@ -345,7 +361,6 @@ void delete_ust_app_channel(int sock, struct ust_app_channel *ua_chan, assert(!ret); delete_ust_app_event(sock, ua_event); } - lttng_ht_destroy(ua_chan->events); /* Wipe and free registry from session registry. */ registry = get_session_registry(ua_chan->session); @@ -365,7 +380,7 @@ void delete_ust_app_channel(int sock, struct ust_app_channel *ua_chan, lttng_fd_put(LTTNG_FD_APPS, 1); free(ua_chan->obj); } - free(ua_chan); + call_rcu(&ua_chan->rcu_head, delete_ust_app_channel_rcu); } /* @@ -541,6 +556,22 @@ error: return ret; } +/* + * We need to execute ht_destroy outside of RCU read-side critical + * section, so we postpone its execution using call_rcu. It is simpler + * than to change the semantic of the many callers of + * delete_ust_app_session(). + */ +static +void delete_ust_app_session_rcu(struct rcu_head *head) +{ + struct ust_app_session *ua_sess = + caa_container_of(head, struct ust_app_session, rcu_head); + + lttng_ht_destroy(ua_sess->channels); + free(ua_sess); +} + /* * Delete ust app session safely. RCU read lock must be held before calling * this function. @@ -577,7 +608,6 @@ void delete_ust_app_session(int sock, struct ust_app_session *ua_sess, assert(!ret); delete_ust_app_channel(sock, ua_chan, app); } - lttng_ht_destroy(ua_sess->channels); /* In case of per PID, the registry is kept in the session. */ if (ua_sess->buffer_type == LTTNG_BUFFER_PER_PID) { @@ -595,12 +625,14 @@ void delete_ust_app_session(int sock, struct ust_app_session *ua_sess, sock, ret); } } - free(ua_sess); + call_rcu(&ua_sess->rcu_head, delete_ust_app_session_rcu); } /* * Delete a traceable application structure from the global list. Never call * this function outside of a call_rcu call. + * + * RCU read side lock should _NOT_ be held when calling this function. */ static void delete_ust_app(struct ust_app *app) @@ -608,20 +640,20 @@ void delete_ust_app(struct ust_app *app) int ret, sock; struct ust_app_session *ua_sess, *tmp_ua_sess; - rcu_read_lock(); - /* Delete ust app sessions info */ sock = app->sock; app->sock = -1; - lttng_ht_destroy(app->sessions); - /* Wipe sessions */ cds_list_for_each_entry_safe(ua_sess, tmp_ua_sess, &app->teardown_head, teardown_node) { /* Free every object in the session and the session. */ + rcu_read_lock(); delete_ust_app_session(sock, ua_sess, app); + rcu_read_unlock(); } + + lttng_ht_destroy(app->sessions); lttng_ht_destroy(app->ust_objd); /* @@ -645,8 +677,6 @@ void delete_ust_app(struct ust_app *app) DBG2("UST app pid %d deleted", app->pid); free(app); - - rcu_read_unlock(); } /* @@ -2153,6 +2183,7 @@ static int send_channel_uid_to_ust(struct buffer_reg_channel *reg_chan, ret = ust_consumer_send_stream_to_ust(app, ua_chan, &stream); if (ret < 0) { + (void) release_ust_app_stream(-1, &stream); goto error_stream_unlock; } @@ -2347,7 +2378,7 @@ error: * Create UST app channel and create it on the tracer. Set ua_chanp of the * newly created channel if not NULL. * - * Called with UST app session lock held. + * Called with UST app session lock and RCU read-side lock held. * * Return 0 on success or else a negative value. */ @@ -2373,7 +2404,7 @@ static int create_ust_app_channel(struct ust_app_session *ua_sess, if (ua_chan == NULL) { /* Only malloc can fail here */ ret = -ENOMEM; - goto error; + goto error_alloc; } shadow_copy_channel(ua_chan, uchan); @@ -2401,6 +2432,7 @@ end: error: delete_ust_app_channel(ua_chan->is_sent ? app->sock : -1, ua_chan, app); +error_alloc: return ret; } @@ -2496,8 +2528,8 @@ static int create_ust_app_metadata(struct ust_app_session *ua_sess, metadata->attr.overwrite = DEFAULT_CHANNEL_OVERWRITE; metadata->attr.subbuf_size = default_get_metadata_subbuf_size(); metadata->attr.num_subbuf = DEFAULT_METADATA_SUBBUF_NUM; - metadata->attr.switch_timer_interval = DEFAULT_UST_CHANNEL_SWITCH_TIMER; - metadata->attr.read_timer_interval = DEFAULT_UST_CHANNEL_READ_TIMER; + metadata->attr.switch_timer_interval = DEFAULT_METADATA_SWITCH_TIMER; + metadata->attr.read_timer_interval = DEFAULT_METADATA_READ_TIMER; metadata->attr.output = LTTNG_UST_MMAP; metadata->attr.type = LTTNG_UST_CHAN_METADATA; } else { @@ -2506,13 +2538,6 @@ static int create_ust_app_metadata(struct ust_app_session *ua_sess, metadata->attr.type = LTTNG_UST_CHAN_METADATA; } - /* Get the right consumer socket for the application. */ - socket = consumer_find_socket_by_bitness(app->bits_per_long, consumer); - if (!socket) { - ret = -EINVAL; - goto error_consumer; - } - /* Need one fd for the channel. */ ret = lttng_fd_get(LTTNG_FD_APPS, 1); if (ret < 0) { @@ -2520,6 +2545,13 @@ static int create_ust_app_metadata(struct ust_app_session *ua_sess, goto error; } + /* Get the right consumer socket for the application. */ + socket = consumer_find_socket_by_bitness(app->bits_per_long, consumer); + if (!socket) { + ret = -EINVAL; + goto error_consumer; + } + /* * Keep metadata key so we can identify it on the consumer side. Assign it * to the registry *before* we ask the consumer so we avoid the race of the @@ -2541,7 +2573,6 @@ static int create_ust_app_metadata(struct ust_app_session *ua_sess, * Safe because the metadata obj pointer is not set so the delete below * will not put a FD back again. */ - lttng_fd_put(LTTNG_FD_APPS, 1); goto error_consumer; } @@ -2557,7 +2588,6 @@ static int create_ust_app_metadata(struct ust_app_session *ua_sess, * Safe because the metadata obj pointer is not set so the delete below * will not put a FD back again. */ - lttng_fd_put(LTTNG_FD_APPS, 1); goto error_consumer; } @@ -2565,6 +2595,7 @@ static int create_ust_app_metadata(struct ust_app_session *ua_sess, metadata->key, app->pid); error_consumer: + lttng_fd_put(LTTNG_FD_APPS, 1); delete_ust_app_channel(-1, metadata, app); error: return ret; @@ -3046,6 +3077,8 @@ error: /* * Free and clean all traceable apps of the global list. + * + * Should _NOT_ be called with RCU read-side lock held. */ void ust_app_clean_list(void) { @@ -3076,13 +3109,12 @@ void ust_app_clean_list(void) ret = lttng_ht_del(ust_app_ht_by_notify_sock, &iter); assert(!ret); } + rcu_read_unlock(); /* Destroy is done only when the ht is empty */ lttng_ht_destroy(ust_app_ht); lttng_ht_destroy(ust_app_ht_by_sock); lttng_ht_destroy(ust_app_ht_by_notify_sock); - - rcu_read_unlock(); } /*