From: Mark Michelson Date: Mon, 7 Apr 2008 16:08:45 +0000 (+0000) Subject: This fix prevents a deadlock that was experienced in chan_local. There was X-Git-Tag: 1.4.20-rc1~92 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=7892ddd9f5d68c684c1596d1f51e3bbd333ad800;p=thirdparty%2Fasterisk.git This fix prevents a deadlock that was experienced in chan_local. There was deadlock prevention in place in chan_local, but it would not work in a specific case because the channel was recursively locked. By unlocking the channel prior to calling the generator's generate callback in ast_read_generator_actions(), we prevent the recursive locking, and therefore the deadlock. (closes issue #12307) Reported by: callguy Patches: 12307.patch uploaded by putnopvut (license 60) Tested by: callguy git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@113065 65c4cc65-6c06-0410-ace0-fbb531ad65f3 --- diff --git a/main/channel.c b/main/channel.c index bef5602436..bdad4413c9 100644 --- a/main/channel.c +++ b/main/channel.c @@ -1896,7 +1896,17 @@ static void ast_read_generator_actions(struct ast_channel *chan, struct ast_fram } chan->generatordata = NULL; /* reset, to let writes go through */ + /* This unlock is here based on two assumptions that hold true at this point in the + * code. 1) this function is only called from within __ast_read() and 2) all generators + * call ast_write() in their generate callback. + * + * The reason this is added is so that when ast_write is called, the lock that occurs + * there will not recursively lock the channel. Doing this will cause intended deadlock + * avoidance not to work in deeper functions + */ + ast_channel_unlock(chan); res = chan->generator->generate(chan, tmp, f->datalen, f->samples); + ast_channel_lock(chan); chan->generatordata = tmp; if (res) { if (option_debug > 1)