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From f9c67a13af33f389429e4e760f2023a23a9ac19f Mon Sep 17 00:00:00 2001
From: Anssi Hannula <anssi@mageia.org>
Date: Wed, 4 Jan 2012 00:23:55 +0200
Subject: [PATCH 4/4] 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));
--
2.5.0
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