rss plugin: prevent deadlock between save and watcher threads.

Since the timer fix in [1035], rescheduling ticks the timer, which could cause the timed saving to trigger while a feed mutex was being held. Fix by moving the feed watcher rescheduling out of the mutex synchronization.

Also move other calculations out to hold the mutex for as little as necessary.

1 files changed, 5 insertions, 3 deletions

diff --git a/data/rbot/plugins/rss.rb b/data/rbot/plugins/rss.rb
index 62ce48d9..6451996d 100644
--- a/data/rbot/plugins/rss.rb
+++ b/data/rbot/plugins/rss.rb
@@ -761,12 +761,14 @@ class RSSFeedsPlugin < Plugin
 

       status[:failures] = failures

 

+      timer = nil

       feed.mutex.synchronize do

+	timer = @watch[feed.handle]

         seconds = (feed.refresh_rate || @bot.config['rss.thread_sleep']) * (failures + 1)

-        seconds += seconds * (rand(100)-50)/100

-        debug "watcher for #{feed} going to sleep #{seconds} seconds.."

-        @bot.timer.reschedule(@watch[feed.handle], seconds)

       end

+      seconds += seconds * (rand(100)-50)/100

+      debug "watcher for #{feed} going to sleep #{seconds} seconds.."

+      @bot.timer.reschedule(timer, seconds)

     }

     debug "watcher for #{feed} added"

   end