Date: Mon, 23 Apr 2007 11:55:52 -0400 From: Kris Kennaway <kris@obsecurity.org> To: Kai <kai@xs4all.nl> Cc: stable@freebsd.org Subject: Re: Fatal trap 12: page fault while in kernel mode Message-ID: <20070423155552.GB1006@xor.obsecurity.org> In-Reply-To: <20070423153547.GD20155@xs4all.nl> References: <20070411105332.GC7847@xs4all.nl> <20070419123329.GA10189@xs4all.nl> <20070423153547.GD20155@xs4all.nl>
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--gBBFr7Ir9EOA20Yy Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Apr 23, 2007 at 05:35:47PM +0200, Kai wrote: > On Thu, Apr 19, 2007 at 02:33:29PM +0200, Kai wrote: > > On Wed, Apr 11, 2007 at 12:53:32PM +0200, Kai wrote: > > >=20 > > > Hello all, > > >=20 > > > We're running into regular panics on our webserver after upgrading > > > from 4.x to 6.2-stable: > >=20 >=20 > Hi all, >=20 > To continue this story, a colleague wrote a small program in C that launc= hes > 40 threads to randomly append and write to 10 files on an NFS mounted > filesystem.=20 >=20 > If I keep removing the files on one of the other machines in a while loop, > the first system panics: >=20 > Fatal trap 12: page fault while in kernel mode > cpuid =3D 1; apic id =3D 01 > fault virtual address =3D 0x34 > fault code =3D supervisor read, page not present > instruction pointer =3D 0x20:0xc06bdefa > stack pointer =3D 0x28:0xeb9f69b8 > frame pointer =3D 0x28:0xeb9f69c4 > code segment =3D base 0x0, limit 0xfffff, type 0x1b > =3D DPL 0, pres 1, def32 1, gran 1 > processor eflags =3D interrupt enabled, resume, IOPL =3D 0 > current process =3D 73626 (nfscrash) > trap number =3D 12 > panic: page fault > cpuid =3D 1 > Uptime: 3h2m14s >=20 > Sounds like a nice denial of service problem. I can hand the program to > developers on request. Please send it to me. Panics are always much easier to get fixed if they come with a test case that developer can use to reproduce it. Kris --gBBFr7Ir9EOA20Yy Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (FreeBSD) iD8DBQFGLNcIWry0BWjoQKURAkD+AKDu5NG+iAB8NxPfYyYGqB76SvhxVQCffMa/ 8TLB5wrCMJusQNw3R+QqFHU= =3k9X -----END PGP SIGNATURE----- --gBBFr7Ir9EOA20Yy--
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