[3.0] b93d462 Lock panic buffer before mangling it
Tollef Fog Heen
tfheen at varnish-cache.org
Wed Aug 24 09:24:06 CEST 2011
commit b93d4629215fff606fccd2600bc23512007aa16d
Author: Tollef Fog Heen <tfheen at varnish-software.com>
Date: Fri Aug 19 15:03:44 2011 +0200
Lock panic buffer before mangling it
If we were panic-ing in multiple threads at the same time, the panic
buffer would be partially overwritten. Prevent this with a mutex
diff --git a/bin/varnishd/cache_panic.c b/bin/varnishd/cache_panic.c
index c443b67..9279029 100644
--- a/bin/varnishd/cache_panic.c
+++ b/bin/varnishd/cache_panic.c
@@ -34,6 +34,7 @@
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
+#include <pthread.h>
#ifndef HAVE_EXECINFO_H
#include "compat/execinfo.h"
@@ -56,6 +57,7 @@
*/
static struct vsb vsps, *vsp;
+pthread_mutex_t panicstr_mtx = PTHREAD_MUTEX_INITIALIZER;
/*--------------------------------------------------------------------*/
@@ -294,6 +296,9 @@ pan_ic(const char *func, const char *file, int line, const char *cond,
const char *q;
const struct sess *sp;
+ AZ(pthread_mutex_lock(&panicstr_mtx)); /* Won't be released,
+ we're going to die
+ anyway */
switch(xxx) {
case 3:
VSB_printf(vsp,
diff --git a/bin/varnishd/cache_shmlog.c b/bin/varnishd/cache_shmlog.c
index e0b332d..023c20a 100644
--- a/bin/varnishd/cache_shmlog.c
+++ b/bin/varnishd/cache_shmlog.c
@@ -288,7 +288,7 @@ VSL_Init(void)
vsl_wrap();
VSM_head->starttime = (intmax_t)TIM_real();
- VSM_head->panicstr[0] = '\0';
+ memset(VSM_head->panicstr, '\0', sizeof *VSM_head->panicstr);
memset(VSC_C_main, 0, sizeof *VSC_C_main);
VSM_head->child_pid = getpid();
}
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