From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp.codeaurora.org by pdx-caf-mail.web.codeaurora.org (Dovecot) with LMTP id w4DmClZ4G1v8fAAAmS7hNA ; Sat, 09 Jun 2018 06:48:54 +0000 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 10F6060290; Sat, 9 Jun 2018 06:48:54 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on pdx-caf-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI autolearn=ham autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by smtp.codeaurora.org (Postfix) with ESMTP id 708D360290; Sat, 9 Jun 2018 06:48:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 708D360290 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753125AbeFIGsv (ORCPT + 25 others); Sat, 9 Jun 2018 02:48:51 -0400 Received: from mx2.suse.de ([195.135.220.15]:35960 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751528AbeFIGsu (ORCPT ); Sat, 9 Jun 2018 02:48:50 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (charybdis-ext-too.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id E3EB3ACB2; Sat, 9 Jun 2018 06:48:48 +0000 (UTC) Date: Sat, 09 Jun 2018 08:48:48 +0200 Message-ID: From: Takashi Iwai To: Andrew Morton Cc: Davidlohr Bueso , linux-kernel@vger.kernel.org, Waiman Long Subject: Re: [PATCH] ipc: Limit sysctl value to IPCMNI In-Reply-To: <20180608141659.8a517b128c756b4d0b813c9e@linux-foundation.org> References: <20180608134949.12672-1-tiwai@suse.de> <20180608141659.8a517b128c756b4d0b813c9e@linux-foundation.org> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI/1.14.6 (Maruoka) FLIM/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL/10.8 Emacs/25.3 (x86_64-suse-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 08 Jun 2018 23:16:59 +0200, Andrew Morton wrote: > > On Fri, 8 Jun 2018 15:49:49 +0200 Takashi Iwai wrote: > > > Currently shmmni proc entry accepts all entered integer values, but > > the practical limit is IPCMNI (32768). This confuses user as if a > > bigger value were accepted but not applied correctly. > > > > This patch changes the proc entry to use *_minmax variant to limit the > > accepted values accordingly. > > Waiman Long was working on a (vastly more complicated) patchset to > address this. That's great. Any patch available for testing? > > --- a/ipc/ipc_sysctl.c > > +++ b/ipc/ipc_sysctl.c > > @@ -99,6 +99,7 @@ static int proc_ipc_auto_msgmni(struct ctl_table *table, int write, > > static int zero; > > static int one = 1; > > static int int_max = INT_MAX; > > +static int ipcmni = IPCMNI; > > > > static struct ctl_table ipc_kern_table[] = { > > { > > @@ -120,7 +121,9 @@ static struct ctl_table ipc_kern_table[] = { > > .data = &init_ipc_ns.shm_ctlmni, > > .maxlen = sizeof(init_ipc_ns.shm_ctlmni), > > .mode = 0644, > > - .proc_handler = proc_ipc_dointvec, > > + .proc_handler = proc_ipc_dointvec_minmax, > > + .extra1 = &zero, > > + .extra2 = &ipcmni, > > }, > > { > > .procname = "shm_rmid_forced", > > What is the back-compatibility situation here? It's obviously an error to set such a high value and suppose that it were accepted. So relying on that behavior must be broken in anyway... thanks, Takashi