From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752802Ab0ELKdi (ORCPT ); Wed, 12 May 2010 06:33:38 -0400 Received: from mailout2.w1.samsung.com ([210.118.77.12]:47471 "EHLO mailout2.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751776Ab0ELKdh convert rfc822-to-8bit (ORCPT ); Wed, 12 May 2010 06:33:37 -0400 Date: Wed, 12 May 2010 12:34:02 +0200 From: =?utf-8?B?TWljaGHFgiBOYXphcmV3aWN6?= Subject: Re: [PATCH] USB: gadget: f_mass_storage: fix in fsg_common_init() error recovery In-reply-to: <70376CA23424B34D86F1C7DE6B9973430254343ABD@VSHINMSMBX01.vshodc.lntinfotech.com> To: Viral Mehta , "linux-usb@vger.kernel.org" Cc: Kyungmin Park , Marek Szyprowski , "linux-kernel@vger.kernel.org" Message-id: Organization: Samsung Electronics MIME-version: 1.0 Content-type: text/plain; charset=utf-8; format=flowed; delsp=yes Content-transfer-encoding: 8BIT User-Agent: Opera Mail/10.10 (Linux) References: <994e1bf34d3b6f1fbc58c0f7ce61c7f258208ddd.1273651956.git.mina86@mina86.com> <70376CA23424B34D86F1C7DE6B9973430254343ABA@VSHINMSMBX01.vshodc.lntinfotech.com> <70376CA23424B34D86F1C7DE6B9973430254343ABB@VSHINMSMBX01.vshodc.lntinfotech.com> <70376CA23424B34D86F1C7DE6B9973430254343ABD@VSHINMSMBX01.vshodc.lntinfotech.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 12 May 2010 12:06:11 +0200, Viral Mehta wrote: > In fsg_common_release(), we are freeing common->luns. > 2894 kfree(common->luns); > > However, these gets allocd in fsg_common_init() > 2712 /* Create the LUNs, open their backing files, and register the > 2713 * LUN devices in sysfs. */ > 2714 curlun = kzalloc(nluns * sizeof *curlun, GFP_KERNEL); > 2715 if (!curlun) { > 2716 kfree(common); > 2717 return ERR_PTR(-ENOMEM); > 2718 } > > Now, if this kzalloc at line 2714 failed > And if your patch is applied, you will follow error_release path which in > turn will call kfree on a pointer whose allocation is failed. If luns allocation fails, common->luns will be NULL and freeing a NULL pointer is a no-operation thus the code works just fine. -- Best regards, _ _ | Humble Liege of Serenely Enlightened Majesty of o' \,=./ `o | Computer Science, Michał "mina86" Nazarewicz (o o) +----[mina86*mina86.com]---[mina86*jabber.org]----ooO--(_)--Ooo--