Date: Thu, 07 Mar 2002 19:25:01 -0800 (PST) From: randy@rcreighton.org To: freebsd-stable@freebsd.org Subject: RE: patch (was Re: reproducable panic with python) Message-ID: <XFMail.20020307192501.randy@rcreighton.org> In-Reply-To: <200203070351.g273pdb63445@apollo.backplane.com>
next in thread | previous in thread | raw e-mail | index | archive | help
Sorry for seeming like a dunderhead, but I have a 486 that will compile a
kernel without problems but crashes with a page fault under heavy load while
running as a natd gateway. I chalked it up to intermittant hardware, will this
patch possibly fix my problem?
thanks,
Randy
On 07-Mar-2002 Matthew Dillon wrote:
> This should fix it. Included below is the test program to reproduce
> the panic and the patch that will fix it.
>
> The mmap() that triggers it is a MAP_ANON|MAP_NOSYNC mmap.
>
> I am starting a commit cycle now.
>
> -Matt
>
>#include <sys/types.h>
>#include <sys/mman.h>
>#include <stdio.h>
>#include <fcntl.h>
>#include <unistd.h>
>#include <assert.h>
>
>#define SIZE (512*1024*1024)
>#define SYNC (1*1024*1024)
>
> int
> main(int ac, char **av)
> {
> void *ptr;
>
> ptr = mmap(NULL, 4096, PROT_READ, MAP_ANON, -1, 0);
> assert(ptr != MAP_FAILED);
> ptr = mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_ANON|MAP_NOSYNC, -1, 0);
> assert(ptr != MAP_FAILED);
> msync(ptr, 4096, 0);
> }
>
>
> Index: vm/vm_map.c
> ===================================================================
> RCS file: /home/ncvs/src/sys/vm/vm_map.c,v
> retrieving revision 1.187.2.12
> diff -u -r1.187.2.12 vm_map.c
> --- vm/vm_map.c 10 Nov 2001 22:27:09 -0000 1.187.2.12
> +++ vm/vm_map.c 7 Mar 2002 03:45:42 -0000
> @@ -1741,8 +1741,11 @@
> * to write out.
> * We invalidate (remove) all pages from the address space
> * anyway, for semantic correctness.
> + *
> + * note: certain anonymous maps, such as MAP_NOSYNC maps,
> + * may start out with a NULL object.
> */
> - while (object->backing_object) {
> + while (object && object->backing_object) {
> object = object->backing_object;
> offset += object->backing_object_offset;
> if (object->size < OFF_TO_IDX( offset + size))
>
> To Unsubscribe: send mail to majordomo@FreeBSD.org
> with "unsubscribe freebsd-stable" in the body of the message
--
----------------------------------
E-Mail: randy@rcreighton.org
Date: 07-Mar-2002
Time: 19:19:38
This message was sent by XFMail
----------------------------------
To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-stable" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?XFMail.20020307192501.randy>