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Commit 2f5174e5 authored by Vladislav Vaintroub's avatar Vladislav Vaintroub
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MDEV-33075 Resolve server shutdown issues on macOS, Solaris, and FreeBSD 

This commit addresses multiple server shutdown problems observed on macOS,
Solaris, and FreeBSD:

1. Corrected a non-portable assumption where socket shutdown was expected
to wake up poll() with listening sockets in the main thread.

Use more robust self-pipe to wake up poll() by writing to the pipe's write
end.

2. Fixed a random crash on macOS from pthread_kill(signal_handler)
when the signal_handler was detached and the thread had already exited.

Use more robust `kill(getpid(), SIGTERM)` to wake up the signal handler
thread.

3. Made sure, that signal handler thread always exits once `abort_loop` is
set, and also calls `my_thread_end()` and clears `signal_thread_in_use`
when exiting.

This fixes warning "1 thread did not exit"  by `my_global_thread_end()`
seen on FreeBSD/macOS when the process is terminated via signal.

Additionally, the shutdown code underwent light refactoring
for better readability and maintainability:
- Modified `break_connect_loop()` to no longer wait for the main thread,
  aligning behavior with Windows (since 10.4).
- Removed dead code related to the unused `USE_ONE_SIGNAL_HAND`
  preprocessor constant.
- Eliminated support for `#ifndef HAVE_POLL` in `handle_connection_sockets`
  This code is also dead, since 10.4
parent b0e77c08
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Showing with 53 additions and 151 deletions
sql/mysqld.cc
View file @ 2f5174e5
......@@ -134,9 +134,6 @@
#endif
#include <my_service_manager.h>
#ifdef __linux__
#include <sys/eventfd.h>
#endif
#include <source_revision.h>
......@@ -1396,6 +1393,8 @@ struct my_rnd_struct sql_rand; ///< used by sql_class.cc:THD::THD()
Dynamic_array<MYSQL_SOCKET> listen_sockets(PSI_INSTRUMENT_MEM, 0);
bool unix_sock_is_online= false;
static int systemd_sock_activation; /* systemd socket activation */
/** wakeup listening(main) thread by writing to this descriptor */
static int termination_event_fd= -1;
......@@ -1658,66 +1657,21 @@ static my_bool warn_threads_active_after_phase_2(THD *thd, void *)
static void break_connect_loop()
{
#ifdef EXTRA_DEBUG
int count=0;
#endif
abort_loop= 1;
#if defined(_WIN32)
mysqld_win_initiate_shutdown();
#else
/* Avoid waiting for ourselves when thread-handling=no-threads. */
if (pthread_equal(pthread_self(), select_thread))
return;
DBUG_PRINT("quit", ("waiting for select thread: %lu",
(ulong)select_thread));
mysql_mutex_lock(&LOCK_start_thread);
while (select_thread_in_use)
{
struct timespec abstime;
int UNINIT_VAR(error);
DBUG_PRINT("info",("Waiting for select thread"));
{
/*
Cannot call shutdown on systemd socket activated descriptors
as their clone in the pid 1 is reused.
*/
int lowest_fd, shutdowns= 0;
lowest_fd= sd_listen_fds(0) + SD_LISTEN_FDS_START;
for(size_t i= 0; i < listen_sockets.size(); i++)
{
int fd= mysql_socket_getfd(listen_sockets.at(i));
if (fd >= lowest_fd)
{
shutdowns++;
mysql_socket_shutdown(listen_sockets.at(i), SHUT_RDWR);
}
}
if (!shutdowns && termination_event_fd >=0)
if (termination_event_fd >= 0)
{
uint64_t u= 1;
if (write(termination_event_fd, &u, sizeof(uint64_t)) != sizeof(uint64_t))
sql_print_error("Couldn't send event to terminate listen loop");
}
}
set_timespec(abstime, 2);
for (uint tmp=0 ; tmp < 10 && select_thread_in_use; tmp++)
if(write(termination_event_fd, &u, sizeof(uint64_t)) < 0)
{
error= mysql_cond_timedwait(&COND_start_thread, &LOCK_start_thread,
&abstime);
if (error != EINTR)
break;
sql_print_error("Couldn't send event to terminate listen loop");
abort();
}
#ifdef EXTRA_DEBUG
if (error != 0 && error != ETIMEDOUT && !count++)
sql_print_error("Got error %d from mysql_cond_timedwait", error);
#endif
}
if (termination_event_fd >= 0)
close(termination_event_fd);
mysql_mutex_unlock(&LOCK_start_thread);
#endif /* _WIN32 */
}
......@@ -1963,11 +1917,6 @@ extern "C" void unireg_abort(int exit_code)
static void mysqld_exit(int exit_code)
{
DBUG_ENTER("mysqld_exit");
/*
Important note: we wait for the signal thread to end,
but if a kill -15 signal was sent, the signal thread did
spawn the kill_server_thread thread, which is running concurrently.
*/
rpl_deinit_gtid_waiting();
rpl_deinit_gtid_slave_state();
wait_for_signal_thread_to_end();
......@@ -2124,17 +2073,17 @@ static void clean_up(bool print_message)
*/
static void wait_for_signal_thread_to_end()
{
uint i;
#ifndef _WIN32
/*
Wait up to 10 seconds for signal thread to die. We use this mainly to
avoid getting warnings that my_thread_end has not been called
*/
for (i= 0 ; i < 100 && signal_thread_in_use; i++)
for (uint i= 0 ; i < 100 && signal_thread_in_use; i++)
{
if (pthread_kill(signal_thread, MYSQL_KILL_SIGNAL) == ESRCH)
break;
kill(getpid(), MYSQL_KILL_SIGNAL);
my_sleep(100); // Give it time to die
}
#endif
}
#endif /*EMBEDDED_LIBRARY*/
......@@ -2676,9 +2625,6 @@ static void use_systemd_activated_sockets()
listen_sockets.push(sock);
}
systemd_sock_activation= 1;
termination_event_fd= eventfd(0, EFD_CLOEXEC|EFD_NONBLOCK);
if (termination_event_fd == -1)
sql_print_warning("eventfd failed %d", errno);
free(names);
DBUG_VOID_RETURN;
......@@ -3232,22 +3178,9 @@ static void start_signal_handler(void)
DBUG_VOID_RETURN;
}
#if defined(USE_ONE_SIGNAL_HAND)
pthread_handler_t kill_server_thread(void *arg __attribute__((unused)))
{
my_thread_init(); // Initialize new thread
break_connect_loop();
my_thread_end();
pthread_exit(0);
return 0;
}
#endif
/** This threads handles all signals */
/* ARGSUSED */
pthread_handler_t signal_hand(void *arg __attribute__((unused)))
pthread_handler_t signal_hand(void *)
{
sigset_t set;
int sig;
......@@ -3291,20 +3224,17 @@ pthread_handler_t signal_hand(void *arg __attribute__((unused)))
int error;
int origin;
if (abort_loop)
break;
while ((error= my_sigwait(&set, &sig, &origin)) == EINTR) /* no-op */;
if (cleanup_done)
{
DBUG_PRINT("quit",("signal_handler: calling my_thread_end()"));
my_thread_end();
DBUG_LEAVE; // Must match DBUG_ENTER()
signal_thread_in_use= 0;
pthread_exit(0); // Safety
return 0; // Avoid compiler warnings
}
if (abort_loop)
break;
switch (sig) {
case SIGTERM:
case SIGQUIT:
case SIGKILL:
#ifdef EXTRA_DEBUG
sql_print_information("Got signal %d to shutdown server",sig);
#endif
......@@ -3312,31 +3242,15 @@ pthread_handler_t signal_hand(void *arg __attribute__((unused)))
logger.set_handlers(global_system_variables.sql_log_slow ? LOG_FILE:LOG_NONE,
opt_log ? LOG_FILE:LOG_NONE);
DBUG_PRINT("info",("Got signal: %d abort_loop: %d",sig,abort_loop));
if (!abort_loop)
{
/* Delete the instrumentation for the signal thread */
PSI_CALL_delete_current_thread();
#ifdef USE_ONE_SIGNAL_HAND
pthread_t tmp;
if (unlikely((error= mysql_thread_create(0, /* Not instrumented */
&tmp, &connection_attrib,
kill_server_thread,
(void*) &sig))))
sql_print_error("Can't create thread to kill server (errno= %d)",
error);
#else
my_sigset(sig, SIG_IGN);
break_connect_loop();
#endif
}
DBUG_ASSERT(abort_loop);
break;
case SIGHUP:
#if defined(SI_KERNEL)
if (!abort_loop && origin != SI_KERNEL)
if (origin != SI_KERNEL)
#elif defined(SI_USER)
if (!abort_loop && origin <= SI_USER)
#else
if (!abort_loop)
if (origin <= SI_USER)
#endif
{
int not_used;
......@@ -3363,6 +3277,11 @@ pthread_handler_t signal_hand(void *arg __attribute__((unused)))
break; /* purecov: tested */
}
}
DBUG_PRINT("quit", ("signal_handler: calling my_thread_end()"));
my_thread_end();
DBUG_LEAVE; // Must match DBUG_ENTER()
signal_thread_in_use= 0;
pthread_exit(0); // Safety
return(0); /* purecov: deadcode */
}
......@@ -6270,16 +6189,11 @@ void handle_connections_sockets()
uint error_count=0;
struct sockaddr_storage cAddr;
int retval;
#ifdef HAVE_POLL
// for ip_sock, unix_sock and extra_ip_sock
Dynamic_array<struct pollfd> fds(PSI_INSTRUMENT_MEM);
#else
fd_set readFDs,clientFDs;
#endif
DBUG_ENTER("handle_connections_sockets");
#ifdef HAVE_POLL
for (size_t i= 0; i < listen_sockets.size(); i++)
{
struct pollfd local_fds;
......@@ -6289,27 +6203,25 @@ void handle_connections_sockets()
fds.push(local_fds);
set_non_blocking_if_supported(listen_sockets.at(i));
}
#else
FD_ZERO(&clientFDs);
for (size_t i= 0; i < listen_sockets.size(); i++)
int termination_fds[2];
if (pipe(termination_fds))
{
int fd= mysql_socket_getfd(listen_sockets.at(i));
FD_SET(fd, &clientFDs);
set_non_blocking_if_supported(listen_sockets.at(i));
sql_print_error("pipe() failed %d", errno);
DBUG_VOID_RETURN;
}
#ifdef FD_CLOEXEC
for (int fd : termination_fds)
(void)fcntl(fd, F_SETFD, FD_CLOEXEC);
#endif
if (termination_event_fd >= 0)
{
#ifdef HAVE_POLL
mysql_mutex_lock(&LOCK_start_thread);
termination_event_fd= termination_fds[1];
mysql_mutex_unlock(&LOCK_start_thread);
struct pollfd event_fd;
event_fd.fd= termination_event_fd;
event_fd.fd= termination_fds[0];
event_fd.events= POLLIN;
fds.push(event_fd);
#else
FD_SET(termination_event_fd, &clientFDs);
#endif
/* no need to read this fd, abrt_loop is set before it gets a chance */
}
sd_notify(0, "READY=1\n"
"STATUS=Taking your SQL requests now...\n");
......@@ -6317,12 +6229,7 @@ void handle_connections_sockets()
DBUG_PRINT("general",("Waiting for connections."));
while (!abort_loop)
{
#ifdef HAVE_POLL
retval= poll(fds.get_pos(0), fds.size(), -1);
#else
readFDs=clientFDs;
retval= select(FD_SETSIZE, &readFDs, NULL, NULL, NULL);
#endif
if (retval < 0)
{
......@@ -6344,7 +6251,6 @@ void handle_connections_sockets()
break;
/* Is this a new connection request ? */
#ifdef HAVE_POLL
for (size_t i= 0; i < fds.size(); ++i)
{
if (fds.at(i).revents & POLLIN)
......@@ -6353,16 +6259,6 @@ void handle_connections_sockets()
break;
}
}
#else // HAVE_POLL
for (size_t i=0; i < listen_sockets.size(); i++)
{
if (FD_ISSET(mysql_socket_getfd(listen_sockets.at(i)), &readFDs))
{
sock= listen_sockets.at(i);
break;
}
}
#endif // HAVE_POLL
for (uint retry=0; retry < MAX_ACCEPT_RETRY && !abort_loop; retry++)
{
......@@ -6390,6 +6286,12 @@ void handle_connections_sockets()
}
}
}
mysql_mutex_lock(&LOCK_start_thread);
for(int fd : termination_fds)
close(fd);
termination_event_fd= -1;
mysql_mutex_unlock(&LOCK_start_thread);
sd_notify(0, "STOPPING=1\n"
"STATUS=Shutdown in progress\n");
DBUG_VOID_RETURN;
......
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