From 18f50698292ff3b917e715922cb12626212b138f Mon Sep 17 00:00:00 2001 From: Mathieu Desnoyers Date: Sat, 1 Oct 2016 18:59:17 -0400 Subject: [PATCH] Fix: perform TLS fixup in all UST entry points from each thread Each entry point into lttng-ust that end up taking the ust lock need to perform a TLS fixup for each thread. Add a TLS fixup in both listener threads, in fork and base address dump helper libs, and in app context and tracepoint probe registration/unregistration functions, which can be called from application threads. Those ensure we don't take the libc dl lock within the ust lock when performing the TLS lazy fixup. Signed-off-by: Mathieu Desnoyers --- liblttng-ust/lttng-probes.c | 4 ++++ liblttng-ust/lttng-tracer-core.h | 2 ++ liblttng-ust/lttng-ust-comm.c | 22 ++++++++++++++++------ liblttng-ust/lttng-ust-statedump.c | 6 ++++++ 4 files changed, 28 insertions(+), 6 deletions(-) diff --git a/liblttng-ust/lttng-probes.c b/liblttng-ust/lttng-probes.c index bba5cd34..4b525923 100644 --- a/liblttng-ust/lttng-probes.c +++ b/liblttng-ust/lttng-probes.c @@ -194,6 +194,8 @@ int lttng_probe_register(struct lttng_probe_desc *desc) { int ret = 0; + lttng_ust_fixup_tls(); + /* * If version mismatch, don't register, but don't trigger assert * on caller. The version check just prints an error. @@ -234,6 +236,8 @@ int ltt_probe_register(struct lttng_probe_desc *desc) void lttng_probe_unregister(struct lttng_probe_desc *desc) { + lttng_ust_fixup_tls(); + if (!check_provider_version(desc)) return; diff --git a/liblttng-ust/lttng-tracer-core.h b/liblttng-ust/lttng-tracer-core.h index 4e0d2c69..f8a60640 100644 --- a/liblttng-ust/lttng-tracer-core.h +++ b/liblttng-ust/lttng-tracer-core.h @@ -50,4 +50,6 @@ void lttng_ust_sockinfo_session_enabled(void *owner); void lttng_ust_malloc_wrapper_init(void); +void lttng_ust_fixup_tls(void); + #endif /* _LTTNG_TRACER_CORE_H */ diff --git a/liblttng-ust/lttng-ust-comm.c b/liblttng-ust/lttng-ust-comm.c index 7842af79..373a1c2d 100644 --- a/liblttng-ust/lttng-ust-comm.c +++ b/liblttng-ust/lttng-ust-comm.c @@ -370,6 +370,16 @@ void lttng_fixup_urcu_bp_tls(void) rcu_read_unlock(); } +void lttng_ust_fixup_tls(void) +{ + lttng_fixup_urcu_bp_tls(); + lttng_fixup_ringbuffer_tls(); + lttng_fixup_vtid_tls(); + lttng_fixup_nest_count_tls(); + lttng_fixup_procname_tls(); + lttng_fixup_ust_mutex_nest_tls(); +} + int lttng_get_notify_socket(void *owner) { struct sock_info *info = owner; @@ -1218,6 +1228,8 @@ void *ust_listener_thread(void *arg) int sock, ret, prev_connect_failed = 0, has_waited = 0; long timeout; + lttng_ust_fixup_tls(); + /* Restart trying to connect to the session daemon */ restart: if (prev_connect_failed) { @@ -1481,12 +1493,7 @@ void __attribute__((constructor)) lttng_ust_init(void) * to be the dynamic linker mutex) and ust_lock, taken within * the ust lock. */ - lttng_fixup_urcu_bp_tls(); - lttng_fixup_ringbuffer_tls(); - lttng_fixup_vtid_tls(); - lttng_fixup_nest_count_tls(); - lttng_fixup_procname_tls(); - lttng_fixup_ust_mutex_nest_tls(); + lttng_ust_fixup_tls(); /* * We want precise control over the order in which we construct @@ -1717,6 +1724,9 @@ void ust_before_fork(sigset_t *save_sigset) sigset_t all_sigs; int ret; + /* Fixup lttng-ust TLS. */ + lttng_ust_fixup_tls(); + if (URCU_TLS(lttng_ust_nest_count)) return; /* Disable signals */ diff --git a/liblttng-ust/lttng-ust-statedump.c b/liblttng-ust/lttng-ust-statedump.c index 4f989bca..b4d93fdd 100644 --- a/liblttng-ust/lttng-ust-statedump.c +++ b/liblttng-ust/lttng-ust-statedump.c @@ -218,6 +218,12 @@ int do_baddr_statedump(void *owner) if (getenv("LTTNG_UST_WITHOUT_BADDR_STATEDUMP")) return 0; + /* + * Fixup lttng-ust TLS when called from dlopen/dlclose + * instrumentation. + */ + lttng_ust_fixup_tls(); + data.owner = owner; data.exec_found = 0; /* -- 2.34.1