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Fix deadlocks in chan_sip in REFER and BYE handling

Browse Source 
This resolves several deadlocks in chan_sip relating to usage of
ast_channel_bridge_peer and improves accessibility of lock debugging
function calls.

Review: https://reviewboard.asterisk.org/r/2756/
(closes issue ASTERISK-22215)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@396723 65c4cc65-6c06-0410-ace0-fbb531ad65f3
changes/78/78/1
Kinsey Moore 12 years ago
parent e9ac63f9a9
commit 3f46d461bf
3 changed files with 156 additions and 87 deletions
Show Stats Download Patch File Download Diff File

174
channels/chan_sip.c
Unescape View File

@ -18008,23 +18008,30 @@ static int get_refer_info(struct sip_pvt *transferer, struct sip_request *outgoi
/* Give useful transfer information to the dialplan */
if (transferer->owner) {
RAII_VAR(struct ast_channel *, peer, ast_channel_bridge_peer(transferer->owner), ast_channel_cleanup);
RAII_VAR(struct ast_channel *, peer, NULL, ast_channel_cleanup);
RAII_VAR(struct ast_channel *, owner_relock, NULL, ast_channel_cleanup);
RAII_VAR(struct ast_channel *, owner_ref, NULL, ast_channel_cleanup);
/*! pbx_builtin_setvar_helper will attempt to lock the channel. We need
* to be sure it's already locked here so we don't deadlock.
*/
while (peer && ast_channel_trylock(peer)) {
sip_pvt_unlock(transferer);
do {
CHANNEL_DEADLOCK_AVOIDANCE(transferer->owner);
} while (sip_pvt_trylock(transferer));
}
/* Grab a reference to transferer->owner to prevent it from going away */
owner_ref = ast_channel_ref(transferer->owner);
/* Established locking order here is bridge, channel, pvt
* and the bridge will be locked during ast_channel_bridge_peer */
ast_channel_unlock(owner_ref);
sip_pvt_unlock(transferer);
peer = ast_channel_bridge_peer(owner_ref);
if (peer) {
pbx_builtin_setvar_helper(peer, "SIPREFERRINGCONTEXT", transferer->context);
pbx_builtin_setvar_helper(peer, "SIPREFERREDBYHDR", p_referred_by);
ast_channel_unlock(peer);
}
owner_relock = sip_pvt_lock_full(transferer);
if (!owner_relock) {
ast_debug(3, "Unable to reacquire owner channel lock, channel is gone\n");
return -5;
}
}
if (!ast_strlen_zero(p_referred_by)) {
@ -26091,7 +26098,7 @@ static int handle_request_refer(struct sip_pvt *p, struct sip_request *req, uint
int res = 0;
struct blind_transfer_cb_data cb_data;
enum ast_transfer_result transfer_res;
RAII_VAR(struct ast_channel *, transferer, NULL, ao2_cleanup);
RAII_VAR(struct ast_channel *, transferer, NULL, ast_channel_cleanup);
RAII_VAR(struct ast_str *, replaces_str, NULL, ast_free_ptr);
if (req->debug) {
@ -26368,6 +26375,8 @@ static int handle_request_bye(struct sip_pvt *p, struct sip_request *req)
struct ast_channel *c=NULL;
int res;
const char *required;
RAII_VAR(struct ast_channel *, peer_channel, NULL, ast_channel_cleanup);
char quality_buf[AST_MAX_USER_FIELD], *quality;
/* If we have an INCOMING invite that we haven't answered, terminate that transaction */
if (p->pendinginvite && !ast_test_flag(&p->flags[0], SIP_OUTGOING) && !req->ignore) {
@ -26384,70 +26393,88 @@ static int handle_request_bye(struct sip_pvt *p, struct sip_request *req)
check_via(p, req);
sip_alreadygone(p);
/* Get RTCP quality before end of call */
if (p->do_history || p->owner) {
char quality_buf[AST_MAX_USER_FIELD], *quality;
RAII_VAR(struct ast_channel *, bridge, p->owner ? ast_channel_bridge_peer(p->owner) : NULL, ast_channel_cleanup);
if (p->owner) {
RAII_VAR(struct ast_channel *, owner_relock, NULL, ast_channel_cleanup);
RAII_VAR(struct ast_channel *, owner_ref, NULL, ast_channel_cleanup);
/* We need to get the lock on bridge because ast_rtp_instance_set_stats_vars will attempt
* to lock the bridge. This may get hairy...
*/
while (bridge && ast_channel_trylock(bridge)) {
ast_channel_unlock(p->owner);
do {
/* Can't use DEADLOCK_AVOIDANCE since p is an ao2 object */
sip_pvt_unlock(p);
usleep(1);
sip_pvt_lock(p);
} while (p->owner && ast_channel_trylock(p->owner));
}
/* Grab a reference to p->owner to prevent it from going away */
owner_ref = ast_channel_ref(p->owner);
/* Established locking order here is bridge, channel, pvt
* and the bridge will be locked during ast_channel_bridge_peer */
ast_channel_unlock(owner_ref);
sip_pvt_unlock(p);
peer_channel = ast_channel_bridge_peer(owner_ref);
owner_relock = sip_pvt_lock_full(p);
if (!owner_relock) {
ast_debug(3, "Unable to reacquire owner channel lock, channel is gone\n");
return 0;
}
}
if (p->rtp && (quality = ast_rtp_instance_get_quality(p->rtp, AST_RTP_INSTANCE_STAT_FIELD_QUALITY, quality_buf, sizeof(quality_buf)))) {
if (p->do_history) {
/* Get RTCP quality before end of call */
if (p->rtp) {
if (p->do_history) {
if ((quality = ast_rtp_instance_get_quality(p->rtp, AST_RTP_INSTANCE_STAT_FIELD_QUALITY, quality_buf, sizeof(quality_buf)))) {
append_history(p, "RTCPaudio", "Quality:%s", quality);
}
if ((quality = ast_rtp_instance_get_quality(p->rtp, AST_RTP_INSTANCE_STAT_FIELD_QUALITY_JITTER, quality_buf, sizeof(quality_buf)))) {
append_history(p, "RTCPaudioJitter", "Quality:%s", quality);
}
if ((quality = ast_rtp_instance_get_quality(p->rtp, AST_RTP_INSTANCE_STAT_FIELD_QUALITY_LOSS, quality_buf, sizeof(quality_buf)))) {
append_history(p, "RTCPaudioLoss", "Quality:%s", quality);
}
if ((quality = ast_rtp_instance_get_quality(p->rtp, AST_RTP_INSTANCE_STAT_FIELD_QUALITY_RTT, quality_buf, sizeof(quality_buf)))) {
append_history(p, "RTCPaudioRTT", "Quality:%s", quality);
}
}
if ((quality = ast_rtp_instance_get_quality(p->rtp, AST_RTP_INSTANCE_STAT_FIELD_QUALITY_JITTER, quality_buf, sizeof(quality_buf)))) {
append_history(p, "RTCPaudioJitter", "Quality:%s", quality);
}
if ((quality = ast_rtp_instance_get_quality(p->rtp, AST_RTP_INSTANCE_STAT_FIELD_QUALITY_LOSS, quality_buf, sizeof(quality_buf)))) {
append_history(p, "RTCPaudioLoss", "Quality:%s", quality);
}
if ((quality = ast_rtp_instance_get_quality(p->rtp, AST_RTP_INSTANCE_STAT_FIELD_QUALITY_RTT, quality_buf, sizeof(quality_buf)))) {
append_history(p, "RTCPaudioRTT", "Quality:%s", quality);
if (p->owner) {
RAII_VAR(struct ast_channel *, owner_relock, NULL, ast_channel_cleanup);
RAII_VAR(struct ast_channel *, owner_ref, NULL, ast_channel_cleanup);
/* Grab a reference to p->owner to prevent it from going away */
owner_ref = ast_channel_ref(p->owner);
/* Established locking order here is bridge, channel, pvt
* and the bridge and channel will be locked during
* ast_rtp_instance_set_stats_vars */
ast_channel_unlock(owner_ref);
sip_pvt_unlock(p);
ast_rtp_instance_set_stats_vars(owner_ref, p->rtp);
if (peer_channel && IS_SIP_TECH(ast_channel_tech(peer_channel))) {
struct sip_pvt *q = ast_channel_tech_pvt(peer_channel);
if (q && q->rtp) {
ast_rtp_instance_set_stats_vars(peer_channel, q->rtp);
}
}
if (p->owner) {
ast_rtp_instance_set_stats_vars(p->owner, p->rtp);
owner_relock = sip_pvt_lock_full(p);
if (!owner_relock) {
ast_debug(3, "Unable to reacquire owner channel lock, channel is gone\n");
return 0;
}
}
}
if (bridge) {
struct sip_pvt *q = ast_channel_tech_pvt(bridge);
if (IS_SIP_TECH(ast_channel_tech(bridge)) && q && q->rtp) {
ast_rtp_instance_set_stats_vars(bridge, q->rtp);
}
ast_channel_unlock(bridge);
if (p->vrtp && (quality = ast_rtp_instance_get_quality(p->vrtp, AST_RTP_INSTANCE_STAT_FIELD_QUALITY, quality_buf, sizeof(quality_buf)))) {
if (p->do_history) {
append_history(p, "RTCPvideo", "Quality:%s", quality);
}
if (p->owner) {
pbx_builtin_setvar_helper(p->owner, "RTPVIDEOQOS", quality);
}
}
if (p->vrtp && (quality = ast_rtp_instance_get_quality(p->vrtp, AST_RTP_INSTANCE_STAT_FIELD_QUALITY, quality_buf, sizeof(quality_buf)))) {
if (p->do_history) {
append_history(p, "RTCPvideo", "Quality:%s", quality);
}
if (p->owner) {
pbx_builtin_setvar_helper(p->owner, "RTPVIDEOQOS", quality);
}
if (p->trtp && (quality = ast_rtp_instance_get_quality(p->trtp, AST_RTP_INSTANCE_STAT_FIELD_QUALITY, quality_buf, sizeof(quality_buf)))) {
if (p->do_history) {
append_history(p, "RTCPtext", "Quality:%s", quality);
}
if (p->trtp && (quality = ast_rtp_instance_get_quality(p->trtp, AST_RTP_INSTANCE_STAT_FIELD_QUALITY, quality_buf, sizeof(quality_buf)))) {
if (p->do_history) {
append_history(p, "RTCPtext", "Quality:%s", quality);
}
if (p->owner) {
pbx_builtin_setvar_helper(p->owner, "RTPTEXTQOS", quality);
}
if (p->owner) {
pbx_builtin_setvar_helper(p->owner, "RTPTEXTQOS", quality);
}
}
@ -26463,15 +26490,30 @@ static int handle_request_bye(struct sip_pvt *p, struct sip_request *req)
if (!res) {
c = p->owner;
if (c) {
RAII_VAR(struct ast_channel *, bridged_to, ast_channel_bridge_peer(c), ast_channel_cleanup);
if (bridged_to) {
if (peer_channel) {
RAII_VAR(struct ast_channel *, owner_relock, NULL, ast_channel_cleanup);
char *local_context = ast_strdupa(p->context);
char *local_refer_to = ast_strdupa(p->refer->refer_to);
/* Grab a reference to p->owner to prevent it from going away */
ast_channel_ref(c);
/* Don't actually hangup here... */
ast_queue_unhold(c);
ast_channel_unlock(c); /* async_goto can do a masquerade, no locks can be held during a masq */
ast_async_goto(bridged_to, p->context, p->refer->refer_to, 1);
ast_channel_lock(c);
} else
sip_pvt_unlock(p);
ast_async_goto(peer_channel, local_context, local_refer_to, 1);
owner_relock = sip_pvt_lock_full(p);
ast_channel_cleanup(c);
if (!owner_relock) {
ast_debug(3, "Unable to reacquire owner channel lock, channel is gone\n");
return 0;
}
} else {
ast_queue_hangup(p->owner);
}
}
} else {
ast_log(LOG_WARNING, "Invalid transfer information from '%s'\n", ast_sockaddr_stringify(&p->recv));

17
include/asterisk/lock.h
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@ -316,7 +316,22 @@ static inline void __dump_backtrace(struct ast_bt *bt, int canlog)
* \param this_lock_addr lock address to return lock information
* \since 1.6.1
*/
void log_show_lock(void *this_lock_addr);
void ast_log_show_lock(void *this_lock_addr);
/*!
* \brief Generate a lock dump equivalent to "core show locks".
*
* The lock dump generated is generally too large to be output by a
* single ast_verbose/log/debug/etc. call. Only ast_cli() handles it
* properly without changing BUFSIZ in logger.c.
*
* Note: This must be ast_free()d when you're done with it.
*
* \retval An ast_str containing the lock dump
* \retval NULL on error
* \since 12
*/
struct ast_str *ast_dump_locks(void);
/*!
* \brief retrieve lock info for the specified mutex

52
main/utils.c
Unescape View File

@ -927,7 +927,7 @@ static void append_lock_information(struct ast_str **str, struct thr_lock_info *
which will give a stack trace and continue. -- that aught to do the job!
*/
void log_show_lock(void *this_lock_addr)
void ast_log_show_lock(void *this_lock_addr)
{
struct thr_lock_info *lock_info;
struct ast_str *str;
@ -958,24 +958,12 @@ void log_show_lock(void *this_lock_addr)
}
static char *handle_show_locks(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
struct ast_str *ast_dump_locks(void)
{
struct thr_lock_info *lock_info;
struct ast_str *str;
if (!(str = ast_str_create(4096)))
return CLI_FAILURE;
switch (cmd) {
case CLI_INIT:
e->command = "core show locks";
e->usage =
"Usage: core show locks\n"
" This command is for lock debugging. It prints out which locks\n"
"are owned by each active thread.\n";
return NULL;
case CLI_GENERATE:
if (!(str = ast_str_create(4096))) {
return NULL;
}
@ -988,8 +976,9 @@ static char *handle_show_locks(struct ast_cli_entry *e, int cmd, struct ast_cli_
"=== <pending> <lock#> (<file>): <lock type> <line num> <function> <lock name> <lock addr> (times locked)\n"
"===\n", ast_get_version());
if (!str)
return CLI_FAILURE;
if (!str) {
return NULL;
}
pthread_mutex_lock(&lock_infos_lock.mutex);
AST_LIST_TRAVERSE(&lock_infos, lock_info, entry) {
@ -1012,14 +1001,37 @@ static char *handle_show_locks(struct ast_cli_entry *e, int cmd, struct ast_cli_
}
pthread_mutex_unlock(&lock_infos_lock.mutex);
if (!str)
return CLI_FAILURE;
if (!str) {
return NULL;
}
ast_str_append(&str, 0, "=======================================================================\n"
"\n");
if (!str)
return str;
}
static char *handle_show_locks(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
{
struct ast_str *str;
switch (cmd) {
case CLI_INIT:
e->command = "core show locks";
e->usage =
"Usage: core show locks\n"
" This command is for lock debugging. It prints out which locks\n"
"are owned by each active thread.\n";
return NULL;
case CLI_GENERATE:
return NULL;
}
str = ast_dump_locks();
if (!str) {
return CLI_FAILURE;
}
ast_cli(a->fd, "%s", ast_str_buffer(str));

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