#define _LGPL_SOURCE
#include <sys/types.h>
#include <sys/socket.h>
-#include <sys/prctl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <usterr-signal-safe.h>
#include "tracepoint-internal.h"
#include "ltt-tracer-core.h"
+#include "compat.h"
/*
* Has lttng ust comm constructor been called ?
int register_app_to_sessiond(int socket)
{
ssize_t ret;
- int prctl_ret;
struct {
uint32_t major;
uint32_t minor;
reg_msg.uid = getuid();
reg_msg.gid = getgid();
reg_msg.bits_per_long = CAA_BITS_PER_LONG;
- prctl_ret = prctl(PR_GET_NAME, (unsigned long) reg_msg.name, 0, 0, 0);
- if (prctl_ret) {
- ERR("Error executing prctl");
- return -errno;
- }
+ lttng_ust_getprocname(reg_msg.name);
ret = ustcomm_send_unix_sock(socket, ®_msg, sizeof(reg_msg));
if (ret >= 0 && ret != sizeof(reg_msg))
}
static
-void cleanup_sock_info(struct sock_info *sock_info)
+void cleanup_sock_info(struct sock_info *sock_info, int exiting)
{
int ret;
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");
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 local ust listener thread");
}
}
+ /*
+ * 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);
}