From e65ad34770a17b2e38ee497a156ec396e6af8606 Mon Sep 17 00:00:00 2001
From: Richard Mudgett <rmudgett@digium.com>
Date: Wed, 30 May 2012 17:50:38 +0000
Subject: [PATCH] Fix deadlock when executing CLI "pri show channels" and "ss7
show channels" commands.
* Fix sig_pri_lock_owner() to avoid deadlock properly.
* Code pri_grab() better.
* Fix sig_ss7_lock_owner() to avoid deadlock properly.
* Code ss7_grab() better.
(closes issue ASTERISK-19854)
Reported by: Jaxon
Patches:
jira_asterisk_19854_v1.8.6.patch (license #5621) patch uploaded by rmudgett (Modified to do the same thing to sig_ss7)
Tested by: Jaxon
........
Merged revisions 367976 from http://svn.asterisk.org/svn/asterisk/branches/1.8
........
Merged revisions 367978 from http://svn.asterisk.org/svn/asterisk/branches/10
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@367979 65c4cc65-6c06-0410-ace0-fbb531ad65f3
---
channels/sig_pri.c | 36 +++++++++++++++---------------------
channels/sig_ss7.c | 34 ++++++++++++++--------------------
2 files changed, 29 insertions(+), 41 deletions(-)
diff --git a/channels/sig_pri.c b/channels/sig_pri.c
index e94f08ef57..4be5269fc7 100644
--- a/channels/sig_pri.c
+++ b/channels/sig_pri.c
@@ -115,13 +115,6 @@ static int pri_gendigittimeout = 8000;
#define DCHAN_AVAILABLE (DCHAN_NOTINALARM | DCHAN_UP)
-#define PRI_DEADLOCK_AVOIDANCE(p) \
- do { \
- sig_pri_unlock_private(p); \
- usleep(1); \
- sig_pri_lock_private(p); \
- } while (0)
-
static int pri_active_dchan_index(struct sig_pri_span *pri);
static const char *sig_pri_call_level2str(enum sig_pri_call_level level)
@@ -349,23 +342,23 @@ static void sig_pri_deadlock_avoidance_private(struct sig_pri_chan *p)
p->calls->deadlock_avoidance_private(p->chan_pvt);
} else {
/* Fallback to the old way if callback not present. */
- PRI_DEADLOCK_AVOIDANCE(p);
+ sig_pri_unlock_private(p);
+ sched_yield();
+ sig_pri_lock_private(p);
}
}
static void pri_grab(struct sig_pri_chan *p, struct sig_pri_span *pri)
{
- int res;
-
/* Grab the lock first */
- do {
- res = ast_mutex_trylock(&pri->lock);
- if (res) {
- sig_pri_deadlock_avoidance_private(p);
- }
- } while (res);
+ while (ast_mutex_trylock(&pri->lock)) {
+ /* Avoid deadlock */
+ sig_pri_deadlock_avoidance_private(p);
+ }
/* Then break the poll */
- pthread_kill(pri->master, SIGURG);
+ if (pri->master != AST_PTHREADT_NULL) {
+ pthread_kill(pri->master, SIGURG);
+ }
}
/*!
@@ -1205,10 +1198,11 @@ static void sig_pri_lock_owner(struct sig_pri_span *pri, int chanpos)
/* We got the lock */
break;
}
- /* We must unlock the PRI to avoid the possibility of a deadlock */
- ast_mutex_unlock(&pri->lock);
- sig_pri_deadlock_avoidance_private(pri->pvts[chanpos]);
- ast_mutex_lock(&pri->lock);
+
+ /* Avoid deadlock */
+ sig_pri_unlock_private(pri->pvts[chanpos]);
+ DEADLOCK_AVOIDANCE(&pri->lock);
+ sig_pri_lock_private(pri->pvts[chanpos]);
}
}
diff --git a/channels/sig_ss7.c b/channels/sig_ss7.c
index 490d767e8c..8584d8aafb 100644
--- a/channels/sig_ss7.c
+++ b/channels/sig_ss7.c
@@ -67,13 +67,6 @@ static const char *sig_ss7_call_level2str(enum sig_ss7_call_level level)
return "Unknown";
}
-#define SIG_SS7_DEADLOCK_AVOIDANCE(p) \
- do { \
- sig_ss7_unlock_private(p); \
- usleep(1); \
- sig_ss7_lock_private(p); \
- } while (0)
-
static void sig_ss7_unlock_private(struct sig_ss7_chan *p)
{
if (p->calls->unlock_private) {
@@ -94,7 +87,9 @@ static void sig_ss7_deadlock_avoidance_private(struct sig_ss7_chan *p)
p->calls->deadlock_avoidance_private(p->chan_pvt);
} else {
/* Fallback to the old way if callback not present. */
- SIG_SS7_DEADLOCK_AVOIDANCE(p);
+ sig_ss7_unlock_private(p);
+ sched_yield();
+ sig_ss7_lock_private(p);
}
}
@@ -314,10 +309,11 @@ static void sig_ss7_lock_owner(struct sig_ss7_linkset *ss7, int chanpos)
/* We got the lock */
break;
}
- /* We must unlock the SS7 to avoid the possibility of a deadlock */
- ast_mutex_unlock(&ss7->lock);
- sig_ss7_deadlock_avoidance_private(ss7->pvts[chanpos]);
- ast_mutex_lock(&ss7->lock);
+
+ /* Avoid deadlock */
+ sig_ss7_unlock_private(ss7->pvts[chanpos]);
+ DEADLOCK_AVOIDANCE(&ss7->lock);
+ sig_ss7_lock_private(ss7->pvts[chanpos]);
}
}
@@ -1266,17 +1262,15 @@ static inline void ss7_rel(struct sig_ss7_linkset *ss7)
static void ss7_grab(struct sig_ss7_chan *pvt, struct sig_ss7_linkset *ss7)
{
- int res;
/* Grab the lock first */
- do {
- res = ast_mutex_trylock(&ss7->lock);
- if (res) {
- sig_ss7_deadlock_avoidance_private(pvt);
- }
- } while (res);
+ while (ast_mutex_trylock(&ss7->lock)) {
+ /* Avoid deadlock */
+ sig_ss7_deadlock_avoidance_private(pvt);
+ }
/* Then break the poll */
- if (ss7->master != AST_PTHREADT_NULL)
+ if (ss7->master != AST_PTHREADT_NULL) {
pthread_kill(ss7->master, SIGURG);
+ }
}
/*!
--
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