The following reply was made to PR kern/36673; it has been noted by GNATS.

From: yamt@mwd.biglobe.ne.jp (YAMAMOTO Takashi)
To: juan@xtrarom.org
Cc: gnats-bugs@NetBSD.org
Subject: Re: kern/36673 (dubious code is sysmon_envsys)
Date: Mon, 30 Jul 2007 07:53:19 +0900 (JST)

 > On Wed, 25 Jul 2007 11:45:04 +0000 (UTC)
 > yamt@mwd.biglobe.ne.jp (YAMAMOTO Takashi) wrote:
 > 
 > >  can you provide a diff with -p?
 > 
 > Sure, here it is: (I didn't know about -p, it's very useful :-)
 
 can you explain what you are trying to achieve with this change?
 it seems like almost no-op me.  (except that it seems to introduce
 a double-unlock bug of sme_list_mtx on some errors.)
 
 YAMAMOTO Takashi
 
 > Index: sysmon_envsys.c
 > ===================================================================
 > RCS file: /cvsroot/src/sys/dev/sysmon/sysmon_envsys.c,v
 > retrieving revision 1.43
 > diff -b -u -p -r1.43 sysmon_envsys.c
 > --- sysmon_envsys.c	23 Jul 2007 17:51:16 -0000	1.43
 > +++ sysmon_envsys.c	25 Jul 2007 12:34:15 -0000
 > @@ -483,7 +483,6 @@ sysmon_envsys_register(struct sysmon_env
 >  	mutex_enter(&sme_list_mtx);
 >  	LIST_FOREACH(lsme, &sysmon_envsys_list, sme_list) {
 >  	       if (strcmp(lsme->sme_name, sme->sme_name) == 0) {
 > -		       mutex_exit(&sme_list_mtx);
 >  		       error = EEXIST;
 >  		       goto out;
 >  	       }
 > @@ -496,16 +495,14 @@ sysmon_envsys_register(struct sysmon_env
 >  	sme->sme_fsensor = sysmon_envsys_next_sensor_index;
 >  	sysmon_envsys_next_sensor_index += sme->sme_nsensors;
 >  #endif
 > -	mutex_exit(&sme_list_mtx);
 >  	error = sysmon_envsys_createplist(sme);
 >  	if (!error) {
 > -		mutex_enter(&sme_list_mtx);
 >  		LIST_INSERT_HEAD(&sysmon_envsys_list, sme, sme_list);
 >  		sme_uniqsensors = 0;
 > -		mutex_exit(&sme_list_mtx);
 >  	}
 >  
 >  out:
 > +	mutex_exit(&sme_list_mtx);
 >  	return error;
 >  }
 >  
 > @@ -626,6 +623,9 @@ sysmon_envsys_createplist(struct sysmon_
 >  
 >  	nsens = error = 0;
 >  
 > +	KASSERT(mutex_owned(&sme_list_mtx));
 > +	mutex_exit(&sme_list_mtx);
 > +
 >  	/* create the sysmon envsys device array. */
 >  	array = prop_array_create();
 >  	if (array == NULL)
 > @@ -688,6 +688,7 @@ sysmon_envsys_createplist(struct sysmon_
 >  
 >  
 >  	prop_object_release(array);
 > +	mutex_enter(&sme_list_mtx);
 >  	return error;
 >  }
 >  
 > 
 > -- 
 > Juan Romero Pardines	- The NetBSD Project
 > http://plog.xtrarom.org	- NetBSD/pkgsrc news in Spanish