From owner-freebsd-bugs  Mon May 15  8:20:10 2000
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Date: Mon, 15 May 2000 08:20:02 -0700 (PDT)
Message-Id: <200005151520.IAA37843@freefall.freebsd.org>
To: freebsd-bugs@FreeBSD.org
Cc: 
From: "Paul H. Anderson" <pha@pdq.com>
Subject: Re: i386/18095: critical VM mmap/madvise bug
Reply-To: "Paul H. Anderson" <pha@pdq.com>
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The following reply was made to PR i386/18095; it has been noted by GNATS.

From: "Paul H. Anderson" <pha@pdq.com>
To: Matthew Dillon <dillon@apollo.backplane.com>
Cc: FreeBSD-gnats-submit@freebsd.org
Subject: Re: i386/18095: critical VM mmap/madvise bug
Date: Mon, 15 May 2000 11:06:19 -0400 (EDT)

 Hi,
 
 I was able to verify that installation of this fix appears to correct the
 madvise problem at my site on my machines, with my application as well.
 
 I have not done extensive testing of the overall system to see if for some
 reason it introduces anything new, but I doubt it will.
 
 Thank you very much, Matt, and anyone else who worked on fixing the
 problem!  Great job!
 
 Paul
 
 On Sun, 14 May 2000, Matthew Dillon wrote:
 
 >     Paul, try this patch to /usr/src/sys/vm/vm_map.c and tell me if 
 >     it works.  It appears to work for me when I test using your 
 >     test program.
 > 
 > 					-Matt
 > 					Matthew Dillon 
 > 					<dillon@backplane.com>
 > 
 > Index: vm_map.c
 > ===================================================================
 > RCS file: /home/ncvs/src/sys/vm/vm_map.c,v
 > retrieving revision 1.187
 > diff -u -r1.187 vm_map.c
 > --- vm_map.c	2000/02/28 04:10:35	1.187
 > +++ vm_map.c	2000/05/14 18:31:06
 > @@ -1127,15 +1127,19 @@
 >  		     (current != &map->header) && (current->start < end);
 >  		     current = current->next
 >  		) {
 > +			vm_offset_t useStart;
 > +
 >  			if (current->eflags & MAP_ENTRY_IS_SUB_MAP)
 >  				continue;
 >  
 >  			pindex = OFF_TO_IDX(current->offset);
 >  			count = atop(current->end - current->start);
 > +			useStart = current->start;
 >  
 >  			if (current->start < start) {
 >  				pindex += atop(start - current->start);
 >  				count -= atop(start - current->start);
 > +				useStart = start;
 >  			}
 >  			if (current->end > end)
 >  				count -= atop(current->end - end);
 > @@ -1148,7 +1152,7 @@
 >  			if (behav == MADV_WILLNEED) {
 >  				pmap_object_init_pt(
 >  				    map->pmap, 
 > -				    current->start,
 > +				    useStart,
 >  				    current->object.vm_object,
 >  				    pindex, 
 >  				    (count << PAGE_SHIFT),
 > 
 
 +---------------------------------------------------+
 | Paul Anderson           Public Data Queries, Inc. |
 | pha@pdq.com             734-213-4964 x308         |
 +---------------------------------------------------+
 
 


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