From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757654AbaEPQG1 (ORCPT ); Fri, 16 May 2014 12:06:27 -0400 Received: from mga11.intel.com ([192.55.52.93]:19384 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751640AbaEPQG0 (ORCPT ); Fri, 16 May 2014 12:06:26 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.97,1068,1389772800"; d="scan'208";a="533110946" Message-ID: <53763775.3040602@linux.intel.com> Date: Fri, 16 May 2014 09:06:13 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: Peter Zijlstra , Sasha Levin CC: Ingo Molnar , acme@ghostprotocols.net, LKML , Thomas Gleixner , Dave Jones , tytso@mit.edu, price@mit.edu, hannes@stressinduktion.org Subject: Re: BUG_ON drivers/char/random.c:986 (Was: perf: use after free in perf_remove_from_context) References: <5370EBE9.6@oracle.com> <20140516153455.GV11096@twins.programming.kicks-ass.net> In-Reply-To: <20140516153455.GV11096@twins.programming.kicks-ass.net> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/16/2014 08:34 AM, Peter Zijlstra wrote: > > While fuzzing to reproduce my issue I hit the below, its triggered loads > of times and then the machine wedged (needed a power cycle), I can > provide the full console log if people care. > > Anybody seen that one before? > I certainly haven't... this bad. Any idea what the actual system call looked like? The BUG_ON() in question indicates that r->entropy_count either overflowed or underflowed... most likely underflowed I'd guess. -hpa