Date: Mon, 15 May 2000 08:20:02 -0700 (PDT) From: "Paul H. Anderson" <pha@pdq.com> To: freebsd-bugs@FreeBSD.org Subject: Re: i386/18095: critical VM mmap/madvise bug Message-ID: <200005151520.IAA37843@freefall.freebsd.org>
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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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