From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753063AbaIJV7M (ORCPT ); Wed, 10 Sep 2014 17:59:12 -0400 Received: from one.firstfloor.org ([193.170.194.197]:53911 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752441AbaIJV7L (ORCPT ); Wed, 10 Sep 2014 17:59:11 -0400 Date: Wed, 10 Sep 2014 23:59:08 +0200 From: Andi Kleen To: Peter Zijlstra Cc: Andi Kleen , linux-kernel@vger.kernel.org, Stephane Eranian , Ingo Molnar , Vince Weaver Subject: Re: BUG uncore_assign_events Message-ID: <20140910215908.GL4120@two.firstfloor.org> References: <20140910091626.GO16043@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140910091626.GO16043@twins.programming.kicks-ass.net> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > # addr2line -i -e ivb-ep-build/vmlinux ffffffff81025f18 > > arch/x86/include/asm/bitops.h:318 > arch/x86/kernel/cpu/perf_event_intel_uncore.c:3339 i == zero (ok) c points to some kernel looking address hwc->idx is 64 /* fastpath, try to reuse previous register */ for (i = 0; i < n; i++) { hwc = &box->event_list[i]->hw; c = hwc->constraint; /* never assigned */ if (hwc->idx == -1) break; /* constraint still honored */ if (!test_bit(hwc->idx, c->idxmsk)) break; My best bet is something goes wrong in uncore_pmu_to_box or uncore_event_to_pmu in hte caller, so the box is bogus. Did the test do CPU hot plug? BTW i don't think it's a security issue because the uncore driver is only accesible for root. -Andi -- ak@linux.intel.com -- Speaking for myself only.