From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752230AbaIJKDH (ORCPT ); Wed, 10 Sep 2014 06:03:07 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:51053 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750937AbaIJKDE (ORCPT ); Wed, 10 Sep 2014 06:03:04 -0400 Date: Wed, 10 Sep 2014 12:02:57 +0200 From: Peter Zijlstra To: Sasha Levin Cc: paulus@samba.org, Ingo Molnar , acme@ghostprotocols.net, LKML , Dave Jones Subject: Re: perf: NULL ptr deref in perf_event_context_sched_in Message-ID: <20140910100257.GP16043@twins.programming.kicks-ass.net> References: <540F53C9.6040800@oracle.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="qSHHer9gQ0dtepKr" Content-Disposition: inline In-Reply-To: <540F53C9.6040800@oracle.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --qSHHer9gQ0dtepKr Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Sep 09, 2014 at 03:23:53PM -0400, Sasha Levin wrote: > While fuzzing with trinity inside a KVM tools guest running the latest -n= ext > kernel, I've stumbled on the following spew: >=20 > [ 1181.492212] BUG: unable to handle kernel NULL pointer dereference at 0= 000000000000040 > [ 1181.500717] IP: perf_event_context_sched_in (kernel/events/core.c:333 = kernel/events/core.c:2575) Oh joy: static inline struct perf_cpu_context * __get_cpu_context(struct perf_event_context *ctx) { return this_cpu_ptr(ctx->pmu->pmu_cpu_context); } For some reason our pmu::pmu_cpu_context per-cpu storage is gone. Now how did that happen.... /me puzzled --qSHHer9gQ0dtepKr Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJUECHRAAoJEHZH4aRLwOS6SWsQAICJO2lWWoBoXsT2x6cQbcRD pCE83khLsq4EK8x+s/W6hbKYOfnlRRpILGDhNzLeQqI0hfNQt5NiJzpl2MFWeh/B HqKoMq0ol6IY2yw1b4mG2SOCGxetYub8zrLJ+IheTnLg9Gi1D03Ae7it9sGbkOT9 eVtPDjFzAcO5hP6whq137uUEd6H53a/j+EyMX0MzZki7jf6+tMwF6liqDKaAeZZQ 2W/FmHSAiFcDAWIej7zOlExwzGGR9+b8Ajnarkzzro4zHliyInOpH270GkFkxwJ+ OPC1Fh0MrkqWLPoPiwP4fyf//6cDbhfooWrqXr4WF0p3VRCYHVAiClG4SRu3V7K6 ef8EOjzhzecq6cSQDcqb1xo6W4elhQDSbzXKFWCdkN7Zht645kPexpf+1xMA9hfw 6fU72Qrpupjjaq+WabYhX/jTMjZZFE2ZFRbdt/g+/oEmuReXUJolestsNxLT+zsb EYzZAbOw/AcN7/A+nEbAWy0+Nyjh6Usc58FLaROSJcNOYC0e6INQ2RIsi0Uj5yDj cQWihBDRYcsGZLgXVbx9bKND+Z8CC1zhuy7iEu8wLIcDrbAtmGBHUxx4LDqJk/w9 50JmaAcAFqYMR0yirdm6urzVawjzK14oKdEtvVpGbvltOYpHDhW901XwF8joGjKs 31+t1AzgSnmuLPEW7zeO =cOI0 -----END PGP SIGNATURE----- --qSHHer9gQ0dtepKr--