From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755432Ab1GDMUe (ORCPT ); Mon, 4 Jul 2011 08:20:34 -0400 Received: from a.ns.miles-group.at ([95.130.255.143]:56044 "EHLO radon.swed.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754916Ab1GDMUd (ORCPT ); Mon, 4 Jul 2011 08:20:33 -0400 From: Richard Weinberger To: Tetsuo Handa Subject: Re: [PATCH][Resend v2] Fix infinite loop in search_binary_handler() Date: Mon, 4 Jul 2011 14:20:30 +0200 User-Agent: KMail/1.13.7 (Linux/2.6.37.6-0.5-desktop; KDE/4.6.4; x86_64; ; ) Cc: viro@zeniv.linux.org.uk, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org References: <1309779003-8668-1-git-send-email-richard@nod.at> <201107041357.43481.richard@nod.at> <201107042110.EDI30723.OLFHOtQSMOFFJV@I-love.SAKURA.ne.jp> In-Reply-To: <201107042110.EDI30723.OLFHOtQSMOFFJV@I-love.SAKURA.ne.jp> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201107041420.31049.richard@nod.at> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am Montag 04 Juli 2011, 14:10:43 schrieb Tetsuo Handa: > Richard Weinberger wrote: > > Am Montag 04 Juli 2011, 13:51:55 schrieb Tetsuo Handa: > > > Richard Weinberger wrote: > > > > Running a x86_64 kernel without ia32 emulation and a x86 user land > > > > triggers this issue. > > > > > > Executing /sbin/modprobe for x86_32 on an x86_64 kernel without x86_32 > > > support? > > > > Yep. > > > > > Anyway, request_module() calls __request_module() but > > > __request_module() stops at MAX_KMOD_CONCURRENT levels of nesting. > > > So, I think "infinite loop" cannot happen. > > > > Booting a x86_64 UML kernel with x86_32 user land triggers this issue. > > I always wondered why the UML kernel hangs an consumes 100% CPU. > > That's strange... Would you show us printk() output like > > printk(KERN_INFO "Calling request_module()\n"); > request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2])); > printk(KERN_INFO "Returned from request_module()\n"); > > for demonstrating that __request_module() cannot stop at > MAX_KMOD_CONCURRENT levels of nesting? There you go! http://userweb.kernel.org/~rw/boot.log I did not count all messages, but they are more than 50. :-) Thanks, //richard