From 246be17ec5a99beae7cc40eede54b4958958d8fb Mon Sep 17 00:00:00 2001 From: Paul Woegerer Date: Fri, 29 Nov 2013 14:32:54 +0100 Subject: [PATCH] Fix: baddr_statedump deadlock with JUL tracing Signed-off-by: Paul Woegerer Signed-off-by: Mathieu Desnoyers --- include/lttng/ust-events.h | 6 ++++++ liblttng-ust/lttng-events.c | 19 ++++++++++++++++++- liblttng-ust/lttng-tracer-core.h | 3 +-- liblttng-ust/lttng-ust-comm.c | 30 +++++++++++++++++------------- 4 files changed, 42 insertions(+), 16 deletions(-) diff --git a/include/lttng/ust-events.h b/include/lttng/ust-events.h index 5d435708..28f7391b 100644 --- a/include/lttng/ust-events.h +++ b/include/lttng/ust-events.h @@ -513,6 +513,9 @@ struct lttng_session { struct lttng_ust_event_ht events_ht; /* ht of events */ void *owner; /* object owner */ int tstate:1; /* Transient enable state */ + + /* New UST 2.4 */ + int statedump_pending:1; }; struct lttng_transport { @@ -606,4 +609,7 @@ void lttng_filter_sync_state(struct lttng_bytecode_runtime *runtime); struct cds_list_head *lttng_get_probe_list_head(void); int lttng_session_active(void); +typedef int (*t_statedump_func_ptr)(struct lttng_session *session); +int lttng_handle_pending_statedumps(t_statedump_func_ptr statedump_func_ptr); + #endif /* _LTTNG_UST_EVENTS_H */ diff --git a/liblttng-ust/lttng-events.c b/liblttng-ust/lttng-events.c index 77515843..9380e9ce 100644 --- a/liblttng-ust/lttng-events.c +++ b/liblttng-ust/lttng-events.c @@ -294,7 +294,8 @@ int lttng_session_enable(struct lttng_session *session) CMM_ACCESS_ONCE(session->active) = 1; CMM_ACCESS_ONCE(session->been_active) = 1; - lttng_ust_sockinfo_session_enabled(session->owner, session); + session->statedump_pending = 1; + lttng_ust_sockinfo_session_enabled(session->owner); end: return ret; } @@ -674,6 +675,22 @@ int lttng_fix_pending_events(void) return 0; } +/* + * Called after session enable: For each session, execute pending statedumps. + */ +int lttng_handle_pending_statedumps(t_statedump_func_ptr statedump_func_ptr) +{ + 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; +} + /* * Only used internally at session destruction. */ diff --git a/liblttng-ust/lttng-tracer-core.h b/liblttng-ust/lttng-tracer-core.h index e7f549e0..57df175f 100644 --- a/liblttng-ust/lttng-tracer-core.h +++ b/liblttng-ust/lttng-tracer-core.h @@ -45,7 +45,6 @@ const char *lttng_ust_obj_get_name(int id); int lttng_get_notify_socket(void *owner); -void lttng_ust_sockinfo_session_enabled(void *owner, - struct lttng_session *session_enabled); +void lttng_ust_sockinfo_session_enabled(void *owner); #endif /* _LTTNG_TRACER_CORE_H */ diff --git a/liblttng-ust/lttng-ust-comm.c b/liblttng-ust/lttng-ust-comm.c index b99bf00e..4724fabc 100644 --- a/liblttng-ust/lttng-ust-comm.c +++ b/liblttng-ust/lttng-ust-comm.c @@ -108,7 +108,7 @@ struct sock_info { char wait_shm_path[PATH_MAX]; char *wait_shm_mmap; - struct lttng_session *session_enabled; + int session_enabled; }; /* Socket from app (connect) to session daemon (listen) for communication */ @@ -126,7 +126,7 @@ struct sock_info global_apps = { .wait_shm_path = "/" LTTNG_UST_WAIT_FILENAME, - .session_enabled = NULL, + .session_enabled = 0, }; /* TODO: allow global_apps_sock_path override */ @@ -141,7 +141,7 @@ struct sock_info local_apps = { .socket = -1, .notify_socket = -1, - .session_enabled = NULL, + .session_enabled = 0, }; static int wait_poll_fallback; @@ -708,6 +708,17 @@ error: return ret; } +static +void handle_pending_statedumps(struct sock_info *sock_info) +{ + int ctor_passed = sock_info->constructor_sem_posted; + + if (ctor_passed && sock_info->session_enabled) { + sock_info->session_enabled = 0; + lttng_handle_pending_statedumps(<tng_ust_baddr_statedump); + } +} + static void cleanup_sock_info(struct sock_info *sock_info, int exiting) { @@ -1214,13 +1225,7 @@ restart: if (ret) { ERR("Error handling message for %s socket", sock_info->name); } else { - struct lttng_session *session; - - session = sock_info->session_enabled; - if (session) { - sock_info->session_enabled = NULL; - lttng_ust_baddr_statedump(session); - } + handle_pending_statedumps(sock_info); } continue; default: @@ -1535,9 +1540,8 @@ void ust_after_fork_child(sigset_t *restore_sigset) lttng_ust_init(); } -void lttng_ust_sockinfo_session_enabled(void *owner, - struct lttng_session *session_enabled) +void lttng_ust_sockinfo_session_enabled(void *owner) { struct sock_info *sock_info = owner; - sock_info->session_enabled = session_enabled; + sock_info->session_enabled = 1; } -- 2.34.1