Fix POTS flash hook to orignate a second call deadlock.

A deadlock can occur when a POTS phone tries to flash hook to originate a
second call for 3-way or transfer.  If another process is scanning the
channels container when the POTS line flash hooks then a deadlock will
occur.

* Release the channel and private locks when creating a new channel as a
result of a flash hook.

(closes issue ASTERISK-19842)
Reported by: rmudgett
Tested by: rmudgett
........

Merged revisions 368644 from http://svn.asterisk.org/svn/asterisk/branches/1.8
........

Merged revisions 368645 from http://svn.asterisk.org/svn/asterisk/branches/10

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@368646 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/channels/chan_dahdi.c b/channels/chan_dahdi.c
index 0db84df..46c4589 100644 (file)
--- a/channels/chan_dahdi.c
+++ b/channels/chan_dahdi.c
@@ -8603,8 +8603,18 @@ static struct ast_frame *dahdi_handle_event(struct ast_channel *ast)
                                                ast_log(LOG_WARNING, "Unable to allocate three-way subchannel\n");
                                                goto winkflashdone;
                                        }
-                                       /* Make new channel */
+
+                                       /*
+                                        * Make new channel
+                                        *
+                                        * We cannot hold the p or ast locks while creating a new
+                                        * channel.
+                                        */
+                                       ast_mutex_unlock(&p->lock);
+                                       ast_channel_unlock(ast);
                                        chan = dahdi_new(p, AST_STATE_RESERVED, 0, SUB_THREEWAY, 0, NULL);
+                                       ast_channel_lock(ast);
+                                       ast_mutex_lock(&p->lock);
                                        if (p->dahditrcallerid) {
                                                if (!p->origcid_num)
                                                        p->origcid_num = ast_strdup(p->cid_num);

diff --git a/channels/sig_analog.c b/channels/sig_analog.c
index 6352335..5d71696 100644 (file)
--- a/channels/sig_analog.c
+++ b/channels/sig_analog.c
@@ -3205,8 +3205,18 @@ static struct ast_frame *__analog_handle_event(struct analog_pvt *p, struct ast_
                                                ast_log(LOG_WARNING, "Unable to allocate three-way subchannel\n");
                                                goto winkflashdone;
                                        }
-                                       /* Make new channel */
+
+                                       /*
+                                        * Make new channel
+                                        *
+                                        * We cannot hold the p or ast locks while creating a new
+                                        * channel.
+                                        */
+                                       analog_unlock_private(p);
+                                       ast_channel_unlock(ast);
                                        chan = analog_new_ast_channel(p, AST_STATE_RESERVED, 0, ANALOG_SUB_THREEWAY, NULL);
+                                       ast_channel_lock(ast);
+                                       analog_lock_private(p);
                                        if (!chan) {
                                                ast_log(LOG_WARNING,
                                                        "Cannot allocate new call structure on channel %d\n",