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Merged revisions 187428 via svnmerge from 

https://origsvn.digium.com/svn/asterisk/branches/1.4

........
  r187428 | tilghman | 2009-04-09 13:08:20 -0500 (Thu, 09 Apr 2009) | 8 lines
  
  Race condition between ast_cli_command() and 'module unload' could cause a deadlock.
  Add lock timeouts to avoid this potential deadlock.
  (closes issue #14705)
   Reported by: jamessan
   Patches: 
         20090320__bug14705.diff.txt uploaded by tilghman (license 14)
   Tested by: jamessan
........


git-svn-id: http://svn.digium.com/svn/asterisk/trunk@187483 f38db490-d61c-443f-a65b-d21fe96a405b
This commit is contained in:
tilghman 2009-04-09 18:40:01 +00:00
parent b7e3c49c28
commit fefac6b6c0
3 changed files with 208 additions and 6 deletions
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25
include/asterisk/linkedlists.h
View File

@ -51,6 +51,18 @@
#define AST_RWLIST_WRLOCK(head) \
ast_rwlock_wrlock(&(head)->lock)
/*!
\brief Write locks a list, with timeout.
\param head This is a pointer to the list head structure
\param tv Pointer to a timeval structure
This macro attempts to place an exclusive write lock in the
list head structure pointed to by head.
\retval 0 on success
\retval non-zero on failure
*/
#define AST_RWLIST_TIMEDWRLOCK(head,tv) ast_rwlock_timedwrlock(&(head)->lock, tv)
/*!
\brief Read locks a list.
\param head This is a pointer to the list head structure
@ -63,6 +75,19 @@
#define AST_RWLIST_RDLOCK(head) \
ast_rwlock_rdlock(&(head)->lock)
/*!
\brief Read locks a list, with timeout.
\param head This is a pointer to the list head structure
\param tv Pointer to a timeval structure
This macro attempts to place a read lock in the
list head structure pointed to by head.
\retval 0 on success
\retval non-zero on failure
*/
#define AST_RWLIST_TIMEDRDLOCK(head,tv) \
ast_rwlock_timedrdlock(&(head)->lock, tv)
/*!
\brief Locks a list, without blocking if the list is locked.
\param head This is a pointer to the list head structure

166
include/asterisk/lock.h
View File

@ -1353,6 +1353,162 @@ static inline int _ast_rwlock_wrlock(ast_rwlock_t *t, const char *name,
return res;
}
#define ast_rwlock_timedrdlock(a,b) \
_ast_rwlock_timedrdlock(a, # a, b, __FILE__, __LINE__, __PRETTY_FUNCTION__)
static inline int _ast_rwlock_timedrdlock(ast_rwlock_t *t, const char *name,
const struct timespec *abs_timeout, const char *filename, int line, const char *func)
{
int res;
struct ast_lock_track *lt = &t->track;
int canlog = strcmp(filename, "logger.c") & t->tracking;
#ifdef HAVE_BKTR
struct ast_bt *bt = NULL;
#endif
#ifdef AST_MUTEX_INIT_W_CONSTRUCTORS
if ((t->lock) == ((pthread_rwlock_t) __AST_RWLOCK_INIT_VALUE)) {
/* Don't warn abount uninitialized lock.
* Simple try to initialize it.
* May be not needed in linux system.
*/
res = __ast_rwlock_init(t->tracking, filename, line, func, name, t);
if ((t->lock) == ((pthread_rwlock_t) __AST_RWLOCK_INIT_VALUE)) {
__ast_mutex_logger("%s line %d (%s): Error: rwlock '%s' is uninitialized and unable to initialize.\n",
filename, line, func, name);
return res;
}
}
#endif /* AST_MUTEX_INIT_W_CONSTRUCTORS */
if (t->tracking) {
#ifdef HAVE_BKTR
ast_reentrancy_lock(lt);
if (lt->reentrancy != AST_MAX_REENTRANCY) {
ast_bt_get_addresses(&lt->backtrace[lt->reentrancy]);
bt = &lt->backtrace[lt->reentrancy];
}
ast_reentrancy_unlock(lt);
ast_store_lock_info(AST_WRLOCK, filename, line, func, name, t, bt);
#else
ast_store_lock_info(AST_WRLOCK, filename, line, func, name, t);
#endif
}
res = pthread_rwlock_timedrdlock(&t->lock, abs_timeout);
if (!res) {
ast_reentrancy_lock(lt);
if (lt->reentrancy < AST_MAX_REENTRANCY) {
lt->file[lt->reentrancy] = filename;
lt->lineno[lt->reentrancy] = line;
lt->func[lt->reentrancy] = func;
lt->thread[lt->reentrancy] = pthread_self();
lt->reentrancy++;
}
ast_reentrancy_unlock(lt);
if (t->tracking) {
ast_mark_lock_acquired(t);
}
} else {
#ifdef HAVE_BKTR
if (lt->reentrancy) {
ast_reentrancy_lock(lt);
bt = &lt->backtrace[lt->reentrancy-1];
} else {
bt = NULL;
}
if (t->tracking) {
ast_remove_lock_info(t, bt);
}
#else
if (t->tracking) {
ast_remove_lock_info(t);
}
#endif
__ast_mutex_logger("%s line %d (%s): Error obtaining read lock: %s\n",
filename, line, func, strerror(res));
DO_THREAD_CRASH;
}
return res;
}
#define ast_rwlock_timedwrlock(a,b) \
_ast_rwlock_timedwrlock(a, # a, b, __FILE__, __LINE__, __PRETTY_FUNCTION__)
static inline int _ast_rwlock_timedwrlock(ast_rwlock_t *t, const char *name,
const struct timespec *abs_timeout, const char *filename, int line, const char *func)
{
int res;
struct ast_lock_track *lt = &t->track;
int canlog = strcmp(filename, "logger.c") & t->tracking;
#ifdef HAVE_BKTR
struct ast_bt *bt = NULL;
#endif
#ifdef AST_MUTEX_INIT_W_CONSTRUCTORS
if ((t->lock) == ((pthread_rwlock_t) __AST_RWLOCK_INIT_VALUE)) {
/* Don't warn abount uninitialized lock.
* Simple try to initialize it.
* May be not needed in linux system.
*/
res = __ast_rwlock_init(t->tracking, filename, line, func, name, t);
if ((t->lock) == ((pthread_rwlock_t) __AST_RWLOCK_INIT_VALUE)) {
__ast_mutex_logger("%s line %d (%s): Error: rwlock '%s' is uninitialized and unable to initialize.\n",
filename, line, func, name);
return res;
}
}
#endif /* AST_MUTEX_INIT_W_CONSTRUCTORS */
if (t->tracking) {
#ifdef HAVE_BKTR
ast_reentrancy_lock(lt);
if (lt->reentrancy != AST_MAX_REENTRANCY) {
ast_bt_get_addresses(&lt->backtrace[lt->reentrancy]);
bt = &lt->backtrace[lt->reentrancy];
}
ast_reentrancy_unlock(lt);
ast_store_lock_info(AST_WRLOCK, filename, line, func, name, t, bt);
#else
ast_store_lock_info(AST_WRLOCK, filename, line, func, name, t);
#endif
}
res = pthread_rwlock_timedwrlock(&t->lock, abs_timeout);
if (!res) {
ast_reentrancy_lock(lt);
if (lt->reentrancy < AST_MAX_REENTRANCY) {
lt->file[lt->reentrancy] = filename;
lt->lineno[lt->reentrancy] = line;
lt->func[lt->reentrancy] = func;
lt->thread[lt->reentrancy] = pthread_self();
lt->reentrancy++;
}
ast_reentrancy_unlock(lt);
if (t->tracking) {
ast_mark_lock_acquired(t);
}
} else {
#ifdef HAVE_BKTR
if (lt->reentrancy) {
ast_reentrancy_lock(lt);
bt = &lt->backtrace[lt->reentrancy-1];
} else {
bt = NULL;
}
if (t->tracking) {
ast_remove_lock_info(t, bt);
}
#else
if (t->tracking) {
ast_remove_lock_info(t);
}
#endif
__ast_mutex_logger("%s line %d (%s): Error obtaining read lock: %s\n",
filename, line, func, strerror(res));
DO_THREAD_CRASH;
}
return res;
}
static inline int _ast_rwlock_tryrdlock(ast_rwlock_t *t, const char *name,
const char *filename, int line, const char *func)
{
@ -1601,6 +1757,11 @@ static inline int ast_rwlock_rdlock(ast_rwlock_t *prwlock)
return pthread_rwlock_rdlock(prwlock);
}
static inline int ast_rwlock_timedrdlock(ast_rwlock_t *prwlock, const struct timespec *abs_timeout)
{
return pthread_rwlock_timedrdlock(prwlock, abs_timeout);
}
static inline int ast_rwlock_tryrdlock(ast_rwlock_t *prwlock)
{
return pthread_rwlock_tryrdlock(prwlock);
@ -1611,6 +1772,11 @@ static inline int ast_rwlock_wrlock(ast_rwlock_t *prwlock)
return pthread_rwlock_wrlock(prwlock);
}
static inline int ast_rwlock_timedwrlock(ast_rwlock_t *prwlock, const struct timespec *abs_timeout)
{
return pthread_rwlock_timedwrlock(prwlock, abs_timeout);
}
static inline int ast_rwlock_trywrlock(ast_rwlock_t *prwlock)
{
return pthread_rwlock_trywrlock(prwlock);

23
main/manager.c
View File

@ -3367,8 +3367,12 @@ int __manager_event(int category, const char *event,
int ast_manager_unregister(char *action)
{
struct manager_action *cur;
struct timespec tv = { 5, };
AST_RWLIST_WRLOCK(&actions);
if (AST_RWLIST_TIMEDWRLOCK(&actions, &tv)) {
ast_log(LOG_ERROR, "Could not obtain lock on manager list\n");
return -1;
}
AST_RWLIST_TRAVERSE_SAFE_BEGIN(&actions, cur, list) {
if (!strcasecmp(action, cur->action)) {
AST_RWLIST_REMOVE_CURRENT(list);
@ -3377,7 +3381,7 @@ int ast_manager_unregister(char *action)
break;
}
}
AST_RWLIST_TRAVERSE_SAFE_END;
AST_RWLIST_TRAVERSE_SAFE_END
AST_RWLIST_UNLOCK(&actions);
return 0;
@ -3396,8 +3400,12 @@ static int manager_state_cb(char *context, char *exten, int state, void *data)
static int ast_manager_register_struct(struct manager_action *act)
{
struct manager_action *cur, *prev = NULL;
struct timespec tv = { 5, };
AST_RWLIST_WRLOCK(&actions);
if (AST_RWLIST_TIMEDWRLOCK(&actions, &tv)) {
ast_log(LOG_ERROR, "Could not obtain lock on manager list\n");
return -1;
}
AST_RWLIST_TRAVERSE(&actions, cur, list) {
int ret = strcasecmp(cur->action, act->action);
if (ret == 0) {
@ -3410,8 +3418,8 @@ static int ast_manager_register_struct(struct manager_action *act)
break;
}
}
if (prev)
if (prev)
AST_RWLIST_INSERT_AFTER(&actions, prev, act, list);
else
AST_RWLIST_INSERT_HEAD(&actions, act, list);
@ -3438,7 +3446,10 @@ int ast_manager_register2(const char *action, int auth, int (*func)(struct manse
cur->synopsis = synopsis;
cur->description = description;
ast_manager_register_struct(cur);
if (ast_manager_register_struct(cur)) {
ast_free(cur);
return -1;
}
return 0;
}