Hi,
building and running monit 4.9 on NetBSD 3.1 I encountered a problem
when sending SIGHUP to the process:
Awakened by the SIGHUP signal
Reinitializing monit - Control file '/usr/pkg/etc/monit/monitrc'
monit: Debug: Adding host allow 'localhost'
monit: Debug: Skipping redundant host 'localhost'
Starting monit HTTP server at [localhost:2812]
monit: Error detected by libpthread: Invalid mutex.
Detected by file
"/home/builds/ab/netbsd-3-0-RELEASE/src/lib/libpthread/pthread_
mutex.c", line 334, function "pthread_mutex_unlock".
See pthread(3) for information.
Abort trap (core dumped)
gdb showed this backtrace:
#0 0xbd9fe0bb in kill () from /usr/lib/libc.so.12
#1 0xbdbe52e5 in pthread__errorfunc () from /usr/lib/libpthread.so.0
#2 0xbdbe23d9 in pthread_mutex_unlock () from /usr/lib/libpthread.so.0
#3 0x0804fbb9 in log_log (priority=6,
s=0x80704a0 "Starting %s HTTP server at [%s:%d]\n",
ap=0xbfbfe7e4 "Ðé¿¿ða\n\bü\n") at log.c:377
#4 0x0804f98a in LogInfo (s=0x80704a0 "Starting %s HTTP server at [%s:%d]\n")
at log.c:247
#5 0x0804f765 in monit_http (action=1) at http.c:133
#6 0x0805102a in do_reinit () at monitor.c:339
#7 0x080514e9 in do_default () at monitor.c:506
#8 0x08050ddb in main (argc=8, argv=0xbfbfe8b0) at monitor.c:119
#9 0x0804b156 in ___start ()
After a little investigation, I came up with the following scenario:
- In log.c the mutex "log_mutex" gets initialized at program start (via
PTHREAD_MUTEX_INITIALIZER).
- After receiving SIGHUP the function do_reinit() calls log_close()
which destroys "log_mutex".
- Right after the call to log_close(), log_init() is called again, but
this function does not initialize "log_mutex".
- Subsequent usage of "log_mutex" may or may not crash the process. On
NetBSD, it does.
The appended patch fixes the problem for me, please review.
ciao
Klaus
$NetBSD$
Initialize log_mutex dynamically in log_init(). The static initializiation
via PTHREAD_MUTEX_INITIALIZER is not sufficient because it happens only once,
at program startup.
--- log.c.orig 2007-01-03 22:02:06.000000000 +0100
+++ log.c
@@ -127,6 +127,10 @@ static void log_log(int priority, const
*/
int log_init() {
+ if (pthread_mutex_init(&log_mutex, NULL)) {
+ return FALSE;
+ }
+
if(!Run.dolog) {
return TRUE;
}
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