From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752775AbaH2L1C (ORCPT ); Fri, 29 Aug 2014 07:27:02 -0400 Received: from imap.thunk.org ([74.207.234.97]:55556 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752016AbaH2L1A (ORCPT ); Fri, 29 Aug 2014 07:27:00 -0400 Date: Fri, 29 Aug 2014 07:26:55 -0400 From: "Theodore Ts'o" To: Calvin Owens Cc: Greg Kroah-Hartman , Arnd Bergmann , linux-kernel@vger.kernel.org Subject: Re: BUG: drivers/char/random.c:986 Message-ID: <20140829112655.GB20278@thunk.org> Mail-Followup-To: Theodore Ts'o , Calvin Owens , Greg Kroah-Hartman , Arnd Bergmann , linux-kernel@vger.kernel.org References: <20140829050150.GA3011@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140829050150.GA3011@gmail.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: tytso@thunk.org X-SA-Exim-Scanned: No (on imap.thunk.org); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 28, 2014 at 10:01:50PM -0700, Calvin Owens wrote: > Hello all, > > I hit this BUG_ON() on my laptop a few days ago: http://i.imgur.com/N1GQeJW.jpg > > In the current upstream, this corresponds to line 1022: > > BUG_ON(r->entropy_count > r->poolinfo->poolfracbits); > > It triggered when I executed `dd if=/dev/urandom of=file bs=N count=1` > while watching a YouTube video in Chromium. I don't recall the exact value of > N I used, but it was rather large (>50M), and a few bytes past an even power > of two (I was creating a file to test an HTTP upload script I was working on). > > I haven't had any luck reproducing this on the current upstream or the version > it was originally triggered on. Known bug, fixed in 79a8468747c5 which landed in mainline as of 3.16-rc6. And you were running 3.16-rc4. (BTW, in the future it would be nice if you mentioned the kernel version you were running in; I found it by looking at the jpg, but it's always more convenient to be able to read it in ASCII. :-) Cheers, - Ted