From 8623f2b9e3109b3b743024c6c0790543a936d861 Mon Sep 17 00:00:00 2001 From: mnicholson Date: Thu, 17 Sep 2009 15:38:11 +0000 Subject: Merged revisions 219139 via svnmerge from https://origsvn.digium.com/svn/asterisk/trunk ................ r219139 | mnicholson | 2009-09-17 10:18:01 -0500 (Thu, 17 Sep 2009) | 17 lines Merged revisions 219136 via svnmerge from https://origsvn.digium.com/svn/asterisk/branches/1.4 ........ r219136 | mnicholson | 2009-09-17 09:58:39 -0500 (Thu, 17 Sep 2009) | 10 lines Prevent a potential race condition and crash when hanging up a channel by removing the channel from the channel list before begining channel tear down. This fix may potentially cause problems with CDR backends that access the channel a CDR is associated with via the channel list. This fix makes the channel unavabile at the time when the CDR backend is invoked. This has been documented in include/asterisk/cdr.h. (closes issue #15316) Reported by: vmarrone Tested by: mnicholson Review: https://reviewboard.asterisk.org/r/362/ ........ ................ git-svn-id: http://svn.digium.com/svn/asterisk/branches/1.6.2@219194 f38db490-d61c-443f-a65b-d21fe96a405b --- main/channel.c | 33 +++++++++++++++++++++++++-------- 1 file changed, 25 insertions(+), 8 deletions(-) (limited to 'main') diff --git a/main/channel.c b/main/channel.c index dd92aca92..7b16436c9 100644 --- a/main/channel.c +++ b/main/channel.c @@ -931,6 +931,8 @@ alertpipe_failed: tmp->tech = &null_tech; + ast_set_flag(tmp, AST_FLAG_IN_CHANNEL_LIST); + AST_RWLIST_WRLOCK(&channels); AST_RWLIST_INSERT_HEAD(&channels, tmp, chan_list); AST_RWLIST_UNLOCK(&channels); @@ -1374,17 +1376,21 @@ void ast_channel_free(struct ast_channel *chan) struct varshead *headp; struct ast_datastore *datastore = NULL; char name[AST_CHANNEL_NAME], *dashptr; + int inlist; headp=&chan->varshead; - AST_RWLIST_WRLOCK(&channels); - if (!AST_RWLIST_REMOVE(&channels, chan, chan_list)) { - ast_log(LOG_ERROR, "Unable to find channel in list to free. Assuming it has already been done.\n"); + inlist = ast_test_flag(chan, AST_FLAG_IN_CHANNEL_LIST); + if (inlist) { + AST_RWLIST_WRLOCK(&channels); + if (!AST_RWLIST_REMOVE(&channels, chan, chan_list)) { + ast_debug(1, "Unable to find channel in list to free. Assuming it has already been done.\n"); + } + /* Lock and unlock the channel just to be sure nobody has it locked still + due to a reference retrieved from the channel list. */ + ast_channel_lock(chan); + ast_channel_unlock(chan); } - /* Lock and unlock the channel just to be sure nobody has it locked still - due to a reference retrieved from the channel list. */ - ast_channel_lock(chan); - ast_channel_unlock(chan); /* Get rid of each of the data stores on the channel */ while ((datastore = AST_LIST_REMOVE_HEAD(&chan->datastores, entry))) @@ -1467,7 +1473,8 @@ void ast_channel_free(struct ast_channel *chan) ast_string_field_free_memory(chan); ast_free(chan); - AST_RWLIST_UNLOCK(&channels); + if (inlist) + AST_RWLIST_UNLOCK(&channels); /* Queue an unknown state, because, while we know that this particular * instance is dead, we don't know the state of all other possible @@ -1690,6 +1697,16 @@ int ast_hangup(struct ast_channel *chan) ast_channel_unlock(chan); return 0; } + ast_channel_unlock(chan); + + AST_RWLIST_WRLOCK(&channels); + if (!AST_RWLIST_REMOVE(&channels, chan, chan_list)) { + ast_log(LOG_ERROR, "Unable to find channel in list to free. Assuming it has already been done.\n"); + } + ast_clear_flag(chan, AST_FLAG_IN_CHANNEL_LIST); + AST_RWLIST_UNLOCK(&channels); + + ast_channel_lock(chan); free_translation(chan); /* Close audio stream */ if (chan->stream) { -- cgit v1.2.3