Fix for a deadlock: https://bugzilla.gnome.org/show_bug.cgi?id=667230 From cc14440eface093548cb3bc7814da11d9a99d283 Mon Sep 17 00:00:00 2001 From: Anssi Hannula Date: Wed, 4 Jan 2012 00:23:55 +0200 Subject: [PATCH] fix possible server deadlock in ih_sub_cancel ih_sub_foreach() calls ih_sub_cancel() while inotify_lock is locked. However, ih_sub_cancel() locks it again, and locking GMutex recursively causes undefined behaviour. Fix that by removing locking from ih_sub_cancel() as ih_sub_foreach() is its only user. Also make the function static so that it won't accidentally get used by other files without locking (inotify-helper.h is an internal server header). This should fix the intermittent deadlocks I've been experiencing causing KDE applications to no longer start, and probably also http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=542361 --- server/inotify-helper.c | 7 ++----- server/inotify-helper.h | 1 - 2 files changed, 2 insertions(+), 6 deletions(-) diff --git a/server/inotify-helper.c b/server/inotify-helper.c index d77203e..0789fa4 100644 --- a/server/inotify-helper.c +++ b/server/inotify-helper.c @@ -123,13 +123,11 @@ ih_sub_add (ih_sub_t * sub) /** * Cancels a subscription which was being monitored. + * inotify_lock must be held when calling. */ -gboolean +static gboolean ih_sub_cancel (ih_sub_t * sub) { - G_LOCK(inotify_lock); - - if (!sub->cancelled) { IH_W("cancelling %s\n", sub->pathname); @@ -140,7 +138,6 @@ ih_sub_cancel (ih_sub_t * sub) sub_list = g_list_remove (sub_list, sub); } - G_UNLOCK(inotify_lock); return TRUE; } diff --git a/server/inotify-helper.h b/server/inotify-helper.h index 5d3b6d0..d36b5fd 100644 --- a/server/inotify-helper.h +++ b/server/inotify-helper.h @@ -34,7 +34,6 @@ gboolean ih_startup (event_callback_t ecb, found_callback_t fcb); gboolean ih_running (void); gboolean ih_sub_add (ih_sub_t *sub); -gboolean ih_sub_cancel (ih_sub_t *sub); /* Return FALSE from 'f' if the subscription should be cancelled */ void ih_sub_foreach (void *callerdata, gboolean (*f)(ih_sub_t *sub, void *callerdata)); -- 1.7.7.2