Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932178AbdC2KpQ (ORCPT ); Wed, 29 Mar 2017 06:45:16 -0400 Received: from mx2.suse.de ([195.135.220.15]:60926 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755931AbdC2KoC (ORCPT ); Wed, 29 Mar 2017 06:44:02 -0400 Date: Wed, 29 Mar 2017 12:43:56 +0200 From: Michal Hocko To: Vaneet Narang Cc: Miroslav Benes , Maninder Singh , "jeyu@redhat.com" , "rusty@rustcorp.com.au" , "akpm@linux-foundation.org" , "chris@chris-wilson.co.uk" , "aryabinin@virtuozzo.com" , "joonas.lahtinen@linux.intel.com" , "keescook@chromium.org" , "pavel@ucw.cz" , "jinb.park7@gmail.com" , "anisse@astier.eu" , "rafael.j.wysocki@intel.com" , "zijun_hu@htc.com" , "mingo@kernel.org" , "mawilcox@microsoft.com" , "thgarnie@google.com" , "joelaf@google.com" , "kirill.shutemov@linux.intel.com" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , PANKAJ MISHRA , Ajeet Kumar Yadav , =?utf-8?B?7J207ZWZ67SJ?= , AMIT SAHRAWAT , =?utf-8?B?656E66a/?= , CPGS Subject: Re: [PATCH v2] module: check if memory leak by module. Message-ID: <20170329104355.GG27994@dhcp22.suse.cz> References: <1490767322-9914-1-git-send-email-maninder1.s@samsung.com> <20170329074522.GB27994@dhcp22.suse.cz> <20170329092332epcms5p10ae8263c6e3ef14eac40e08a09eff9e6@epcms5p1> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170329092332epcms5p10ae8263c6e3ef14eac40e08a09eff9e6@epcms5p1> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1017 Lines: 25 On Wed 29-03-17 09:23:32, Vaneet Narang wrote: > Hi, > > >> Hmm, how can you track _all_ vmalloc allocations done on behalf of the > >> module? It is quite some time since I've checked kernel/module.c but > >> from my vague understading your check is basically only about statically > >> vmalloced areas by module loader. Is that correct? If yes then is this > >> actually useful? Were there any bugs in the loader code recently? What > >> led you to prepare this patch? All this should be part of the changelog! > > First of all there is no issue in kernel/module.c. This patch add functionality > to detect scenario where some kernel module does some memory allocation but gets > unloaded without doing vfree. For example > static int kernel_init(void) > { > char * ptr = vmalloc(400 * 1024); > return 0; > } How can you track that allocation back to the module? Does this patch actually works at all? Also why would be vmalloc more important than kmalloc allocations? -- Michal Hocko SUSE Labs