still mbuf leak in 9.0 / 9.1?

[dennis berger]

This is indeed a ZFS+NFS system and I can see that istgt and nfs are stuck in some ZIO state. Maybe it's this. 
Thank's for pointing out. 

Is it this ZFS+NFS deadlock?

--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c 
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/arc.c 
@@ -3720,8 +3720,16 @@ arc_lowmem(void *arg __unused, int howto __unused) 
 	mutex_enter(&arc_reclaim_thr_lock); 
 	needfree = 1; 
 	cv_signal(&arc_reclaim_thr_cv); 
-	while (needfree) 
-	 msleep(&needfree, &arc_reclaim_thr_lock, 0, "zfs:lowmem", 0); 
+ 
+	/* 
+	 * It is unsafe to block here in arbitrary threads, because we can come 
+	 * here from ARC itself and may hold ARC locks and thus risk a deadlock 
+	 * with ARC reclaim thread. 
+	 */ 
+	if (curproc == pageproc) { 
+	 while (needfree) 
+	 msleep(&needfree, &arc_reclaim_thr_lock, 0, "zfs:lowmem", 0); 
+	} 
 	mutex_exit(&arc_reclaim_thr_lock); 
 	mutex_exit(&arc_lowmem_lock); 
 }

I'll try to crash our testsystem. I'll assume that stressing NFS backed with ZFS a lot might trigger this bug?

-dennis


Am 16.05.2013 um 00:03 schrieb Steven Hartland:

> ----- Original Message ----- From: "dennis berger" <db at nipsi.de>
>> FreeBSD  9.1-RELEASE FreeBSD 9.1-RELEASE #0 r243825: Tue Dec  4 09:23:10 UTC 2012
>> 
>>> 3. Regarding this:
>>>>> A clean shutdown isn't possible though. It hangs after vnode
>>>>> cleaning, normally you would see detaching of usb devices here, or
>>>>> other devices maybe?
>>> Please don't conflate this with your above issue.  This is almost
>>> certainly unrelated.  Please start a new thread about that if desired.
>> 
>> Maybe this is a misunderstanding normally this system will shutdown cleanly, of course.
>> This hang only appears after the network problem above.
> 
> If this is a ZFS system, its a known issue which is fixed in current,
> stable-9, stable-8 and the upcoming 8.4 release.
> 
> If not and you have USB devices see if the following sysctl helps:
> hw.usb.no_shutdown_wait=1
> 
>   Regards
>   Steve
> 
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