[or-cvs] r14406: On platforms using pthreads, allow a thread to acquire a loc (in tor/trunk: . src/common)
nickm at seul.org
nickm at seul.org
Tue Apr 22 16:00:00 UTC 2008
Author: nickm
Date: 2008-04-22 11:59:59 -0400 (Tue, 22 Apr 2008)
New Revision: 14406
Modified:
tor/trunk/
tor/trunk/ChangeLog
tor/trunk/src/common/compat.c
Log:
r15251 at tombo: nickm | 2008-04-22 11:59:46 -0400
On platforms using pthreads, allow a thread to acquire a lock it already holds. This is crucial for logging: otherwise any log message thrown from inside the logging process (especially from control.c) will deadlock. Win32 CriticalSections are already recursive. Bug spotted by nwf. Bugfix on 0.2.0.16-alpha. Backport candidate. I hope this is portable.
Property changes on: tor/trunk
___________________________________________________________________
svk:merge ticket from /tor/trunk [r15251] on 49666b30-7950-49c5-bedf-9dc8f3168102
Modified: tor/trunk/ChangeLog
===================================================================
--- tor/trunk/ChangeLog 2008-04-22 15:20:46 UTC (rev 14405)
+++ tor/trunk/ChangeLog 2008-04-22 15:59:59 UTC (rev 14406)
@@ -24,6 +24,9 @@
most smartlists hold around 8-12 elements tops.
- Avoid allocating extra space when computing consensuses on
64-bit platforms. Bug spotted by aakova.
+ - Use recursive pthread mutexes in order to avoid deadlock when
+ logging debug-level messages to a controller. Bug spotted by
+ nwf, bugfix on 0.2.0.16-alpha.
o Minor features:
- Allow separate log levels to be configured for different logging
Modified: tor/trunk/src/common/compat.c
===================================================================
--- tor/trunk/src/common/compat.c 2008-04-22 15:20:46 UTC (rev 14405)
+++ tor/trunk/src/common/compat.c 2008-04-22 15:59:59 UTC (rev 14406)
@@ -1735,13 +1735,14 @@
struct tor_mutex_t {
pthread_mutex_t mutex;
};
+static pthread_mutexattr_t attr_reentrant;
/** Allocate and return new lock. */
tor_mutex_t *
tor_mutex_new(void)
{
int err;
tor_mutex_t *mutex = tor_malloc_zero(sizeof(tor_mutex_t));
- err = pthread_mutex_init(&mutex->mutex, NULL);
+ err = pthread_mutex_init(&mutex->mutex, &attr_reentrant);
if (PREDICT_UNLIKELY(err)) {
log_err(LD_GENERAL, "Error %d creating a mutex.", err);
tor_fragile_assert();
@@ -1857,6 +1858,10 @@
void
tor_threads_init(void)
{
+#ifdef USE_PTHREADS
+ pthread_mutexattr_init(&attr_reentrant);
+ pthread_mutexattr_settype(&attr_reentrant, PTHREAD_MUTEX_RECURSIVE);
+#endif
}
#elif defined(USE_WIN32_THREADS)
#if 0
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