The patch cleans up some signal issues.
First, when the vecs locking around reconfigure got shuffled
around earlier, it was removed from sighup. This patch restores
that.
Second, a new sigusr1 handler was created. However the existing
one was never removed. Since signal handlers are per-process, and
not per-thread, the original handler will get overwritten by the
new one, so this patch deletes the original handler.
Third, sighup locks the vecs lock and sigusr1 locks logq_lock.
However, these signals weren't being blocked before threads locked
those locks. This patch blocks those signals while those locks
are being taken to avoid locking deadlocks.
Signed-off-by: Benjamin Marzinski <bmarzins@xxxxxxxxxx>
---
libmultipath/log_pthread.c | 3 +++
multipathd/main.c | 12 +++++-------
2 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/libmultipath/log_pthread.c b/libmultipath/log_pthread.c
index b8f9119..b3daf8f 100644
--- a/libmultipath/log_pthread.c
+++ b/libmultipath/log_pthread.c
@@ -55,14 +55,17 @@ void log_safe (int prio, const char * fmt, va_list ap)
void log_thread_flush (void)
{
+ sigset_t old;
int empty;
do {
+ block_signal(SIGUSR1, &old);
pthread_mutex_lock(&logq_lock);
empty = log_dequeue(la->buff);
pthread_mutex_unlock(&logq_lock);
if (!empty)
log_syslog(la->buff);
+ pthread_sigmask(SIG_SETMASK, &old, NULL);
} while (empty == 0);
}
diff --git a/multipathd/main.c b/multipathd/main.c
index 95264fc..f6e68e8 100644
--- a/multipathd/main.c
+++ b/multipathd/main.c
@@ -1467,7 +1467,9 @@ sighup (int sig)
if (running_state != DAEMON_RUNNING)
return;
+ lock(gvecs->lock);
reconfigure(gvecs);
+ unlock(gvecs->lock);
#ifdef _DEBUG_
dbg_free_final(NULL);
@@ -1481,16 +1483,9 @@ sigend (int sig)
}
static void
-sigusr1 (int sig)
-{
- condlog(3, "SIGUSR1 received");
-}
-
-static void
signal_init(void)
{
signal_set(SIGHUP, sighup);
- signal_set(SIGUSR1, sigusr1);
signal_set(SIGINT, sigend);
signal_set(SIGTERM, sigend);
signal(SIGPIPE, SIG_IGN);
@@ -1646,6 +1641,7 @@ child (void * param)
*/
running_state = DAEMON_CONFIGURE;
+ block_signal(SIGHUP, &set);
lock(vecs->lock);
if (configure(vecs, 1)) {
unlock(vecs->lock);
@@ -1653,6 +1649,7 @@ child (void * param)
exit(1);
}
unlock(vecs->lock);
+ pthread_sigmask(SIG_SETMASK, &set, NULL);
/*
* start threads
@@ -1685,6 +1682,7 @@ child (void * param)
*/
running_state = DAEMON_SHUTDOWN;
pthread_sigmask(SIG_UNBLOCK, &set, NULL);
+ block_signal(SIGUSR1, NULL);
block_signal(SIGHUP, NULL);
lock(vecs->lock);
if (conf->queue_without_daemon == QUE_NO_DAEMON_OFF)
--
1.8.2
--
dm-devel mailing list
dm-devel@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/dm-devel
