#include <usterr-signal-safe.h>
#include "tracepoint-internal.h"
#include "ltt-tracer-core.h"
+#include "../libringbuffer/tlsfixup.h"
/*
* Has lttng ust comm constructor been called ?
const struct lttng_ust_objd_ops *ops;
struct ustcomm_ust_reply lur;
int shm_fd, wait_fd;
+ union ust_args args;
ust_lock();
default:
if (ops->cmd)
ret = ops->cmd(lum->handle, lum->cmd,
- (unsigned long) &lum->u);
+ (unsigned long) &lum->u,
+ &args);
else
ret = -ENOSYS;
break;
//lur.ret_code = USTCOMM_SESSION_FAIL;
lur.ret_code = ret;
}
- switch (lum->cmd) {
- case LTTNG_UST_STREAM:
- /*
- * Special-case reply to send stream info.
- * Use lum.u output.
- */
- lur.u.stream.memory_map_size = lum->u.stream.memory_map_size;
- shm_fd = lum->u.stream.shm_fd;
- wait_fd = lum->u.stream.wait_fd;
- break;
- case LTTNG_UST_METADATA:
- case LTTNG_UST_CHANNEL:
- lur.u.channel.memory_map_size = lum->u.channel.memory_map_size;
- shm_fd = lum->u.channel.shm_fd;
- wait_fd = lum->u.channel.wait_fd;
- break;
- case LTTNG_UST_TRACER_VERSION:
- lur.u.version = lum->u.version;
- break;
- case LTTNG_UST_TRACEPOINT_LIST_GET:
- memcpy(&lur.u.tracepoint, &lum->u.tracepoint, sizeof(lur.u.tracepoint));
- break;
+ if (ret >= 0) {
+ switch (lum->cmd) {
+ case LTTNG_UST_STREAM:
+ /*
+ * Special-case reply to send stream info.
+ * Use lum.u output.
+ */
+ lur.u.stream.memory_map_size = *args.stream.memory_map_size;
+ shm_fd = *args.stream.shm_fd;
+ wait_fd = *args.stream.wait_fd;
+ break;
+ case LTTNG_UST_METADATA:
+ case LTTNG_UST_CHANNEL:
+ lur.u.channel.memory_map_size = *args.channel.memory_map_size;
+ shm_fd = *args.channel.shm_fd;
+ wait_fd = *args.channel.wait_fd;
+ break;
+ case LTTNG_UST_TRACER_VERSION:
+ lur.u.version = lum->u.version;
+ break;
+ case LTTNG_UST_TRACEPOINT_LIST_GET:
+ memcpy(&lur.u.tracepoint, &lum->u.tracepoint, sizeof(lur.u.tracepoint));
+ break;
+ }
}
ret = send_reply(sock, &lur);
if (ret < 0) {
|| lum->cmd == LTTNG_UST_CHANNEL
|| lum->cmd == LTTNG_UST_METADATA)
&& lur.ret_code == USTCOMM_OK) {
+ int sendret = 0;
+
/* we also need to send the file descriptors. */
ret = ustcomm_send_fds_unix_sock(sock,
&shm_fd, &shm_fd,
1, sizeof(int));
if (ret < 0) {
perror("send shm_fd");
- goto error;
+ sendret = ret;
}
+ /*
+ * The sessiond expects 2 file descriptors, even upon
+ * error.
+ */
ret = ustcomm_send_fds_unix_sock(sock,
&wait_fd, &wait_fd,
1, sizeof(int));
perror("send wait_fd");
goto error;
}
+ if (sendret) {
+ ret = sendret;
+ goto error;
+ }
+ }
+ /*
+ * We still have the memory map reference, and the fds have been
+ * sent to the sessiond. We can therefore close those fds. Note
+ * that we keep the write side of the wait_fd open, but close
+ * the read side.
+ */
+ if (lur.ret_code == USTCOMM_OK) {
+ switch (lum->cmd) {
+ case LTTNG_UST_STREAM:
+ if (shm_fd >= 0) {
+ ret = close(shm_fd);
+ if (ret) {
+ PERROR("Error closing stream shm_fd");
+ }
+ *args.stream.shm_fd = -1;
+ }
+ if (wait_fd >= 0) {
+ ret = close(wait_fd);
+ if (ret) {
+ PERROR("Error closing stream wait_fd");
+ }
+ *args.stream.wait_fd = -1;
+ }
+ break;
+ case LTTNG_UST_METADATA:
+ case LTTNG_UST_CHANNEL:
+ if (shm_fd >= 0) {
+ ret = close(shm_fd);
+ if (ret) {
+ PERROR("Error closing channel shm_fd");
+ }
+ *args.channel.shm_fd = -1;
+ }
+ if (wait_fd >= 0) {
+ ret = close(wait_fd);
+ if (ret) {
+ PERROR("Error closing channel wait_fd");
+ }
+ *args.channel.wait_fd = -1;
+ }
+ break;
+ }
}
+
error:
ust_unlock();
return ret;
}
static
-void cleanup_sock_info(struct sock_info *sock_info)
+void cleanup_sock_info(struct sock_info *sock_info, int exiting)
{
int ret;
if (sock_info->socket != -1) {
- ret = close(sock_info->socket);
+ ret = ustcomm_close_unix_sock(sock_info->socket);
if (ret) {
ERR("Error closing apps socket");
}
sock_info->root_handle = -1;
}
sock_info->constructor_sem_posted = 0;
- if (sock_info->wait_shm_mmap) {
+ /*
+ * wait_shm_mmap is used by listener threads outside of the
+ * ust lock, so we cannot tear it down ourselves, because we
+ * cannot join on these threads. Leave this task to the OS
+ * process exit.
+ */
+ if (!exiting && sock_info->wait_shm_mmap) {
ret = munmap(sock_info->wait_shm_mmap, sysconf(_SC_PAGE_SIZE));
if (ret) {
ERR("Error unmapping wait shm");
* shared memory map will have been created.
*/
pid = wait(&status);
- if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
+ if (pid < 0 || !WIFEXITED(status) || WEXITSTATUS(status) != 0) {
wait_shm_fd = -1;
goto end;
}
"Please upgrade your kernel "
"(fix is commit 9ea71503a8ed9184d2d0b8ccc4d269d05f7940ae in Linux kernel "
"mainline). LTTng-UST will use polling mode fallback.");
+ if (ust_debug())
+ PERROR("futex");
}
- PERROR("futex");
}
}
return;
}
if (sock_info->socket != -1) {
- ret = close(sock_info->socket);
+ ret = ustcomm_close_unix_sock(sock_info->socket);
if (ret) {
ERR("Error closing %s apps socket", sock_info->name);
}
void __attribute__((constructor)) lttng_ust_init(void)
{
struct timespec constructor_timeout;
+ sigset_t sig_all_blocked, orig_parent_mask;
int timeout_mode;
int ret;
if (uatomic_xchg(&initialized, 1) == 1)
return;
+ /*
+ * Fixup interdependency between TLS fixup mutex (which happens
+ * to be the dynamic linker mutex) and ust_lock, taken within
+ * the ust lock.
+ */
+ lttng_fixup_event_tls();
+ lttng_fixup_ringbuffer_tls();
+ lttng_fixup_vtid_tls();
+
/*
* We want precise control over the order in which we construct
* our sub-libraries vs starting to receive commands from
if (ret) {
ERR("Error setting up to local apps");
}
- ret = pthread_create(&local_apps.ust_listener, NULL,
- ust_listener_thread, &local_apps);
+ /* A new thread created by pthread_create inherits the signal mask
+ * from the parent. To avoid any signal being received by the
+ * listener thread, we block all signals temporarily in the parent,
+ * while we create the listener thread.
+ */
+ sigfillset(&sig_all_blocked);
+ ret = pthread_sigmask(SIG_SETMASK, &sig_all_blocked, &orig_parent_mask);
+ if (ret) {
+ ERR("pthread_sigmask: %s", strerror(ret));
+ }
+
+ ret = pthread_create(&global_apps.ust_listener, NULL,
+ ust_listener_thread, &global_apps);
+ if (ret) {
+ ERR("pthread_create global: %s", strerror(ret));
+ }
if (local_apps.allowed) {
- ret = pthread_create(&global_apps.ust_listener, NULL,
- ust_listener_thread, &global_apps);
+ ret = pthread_create(&local_apps.ust_listener, NULL,
+ ust_listener_thread, &local_apps);
+ if (ret) {
+ ERR("pthread_create local: %s", strerror(ret));
+ }
} else {
handle_register_done(&local_apps);
}
+ /* Restore original signal mask in parent */
+ ret = pthread_sigmask(SIG_SETMASK, &orig_parent_mask, NULL);
+ if (ret) {
+ ERR("pthread_sigmask: %s", strerror(ret));
+ }
+
switch (timeout_mode) {
case 1: /* timeout wait */
do {
static
void lttng_ust_cleanup(int exiting)
{
- cleanup_sock_info(&global_apps);
+ cleanup_sock_info(&global_apps, exiting);
if (local_apps.allowed) {
- cleanup_sock_info(&local_apps);
+ cleanup_sock_info(&local_apps, exiting);
}
+ /*
+ * The teardown in this function all affect data structures
+ * accessed under the UST lock by the listener thread. This
+ * lock, along with the lttng_ust_comm_should_quit flag, ensure
+ * that none of these threads are accessing this data at this
+ * point.
+ */
lttng_ust_abi_exit();
lttng_ust_events_exit();
ltt_ring_buffer_client_discard_exit();
lttng_ust_comm_should_quit = 1;
ust_unlock();
+ /* cancel threads */
ret = pthread_cancel(global_apps.ust_listener);
if (ret) {
- ERR("Error cancelling global ust listener thread");
+ ERR("Error cancelling global ust listener thread: %s",
+ strerror(ret));
}
if (local_apps.allowed) {
ret = pthread_cancel(local_apps.ust_listener);
if (ret) {
- ERR("Error cancelling local ust listener thread");
+ ERR("Error cancelling local ust listener thread: %s",
+ strerror(ret));
}
}
+ /*
+ * Do NOT join threads: use of sys_futex makes it impossible to
+ * join the threads without using async-cancel, but async-cancel
+ * is delivered by a signal, which could hit the target thread
+ * anywhere in its code path, including while the ust_lock() is
+ * held, causing a deadlock for the other thread. Let the OS
+ * cleanup the threads if there are stalled in a syscall.
+ */
lttng_ust_cleanup(1);
}
projects / lttng-ust.git / blobdiff