Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758059Ab3HMOuy (ORCPT ); Tue, 13 Aug 2013 10:50:54 -0400 Received: from top.free-electrons.com ([176.31.233.9]:60442 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1757619Ab3HMOux (ORCPT ); Tue, 13 Aug 2013 10:50:53 -0400 Date: Tue, 13 Aug 2013 11:50:43 -0300 From: Ezequiel Garcia To: Nilanjan Roychowdhury Cc: linux-mtd@lists.infradead.org, David Woodhouse , linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/1] Resubmit mtd: mtdoops: fix for a potential memory leak in mtdoops_notify_remove Message-ID: <20130813145041.GB2359@localhost> References: <1376369315-5170-1-git-send-email-nilanjan.roychowdhury@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1376369315-5170-1-git-send-email-nilanjan.roychowdhury@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2264 Lines: 75 Hi Nilanjan, On Mon, Aug 12, 2013 at 09:48:35PM -0700, Nilanjan Roychowdhury wrote: > we are allocating cxt->oops_page_used using vmalloc in mtdoops_notify_add for > every mtd_info addition but not freeing it in mtdoops_notify_remove. Also care is > taken so that we do not free the same pointer again in module remove. > Could you re-send this with a better commit message? In particular we'd like to see why you're doing this, explaining how the current implementation implies a possible leak, explaining under what circumstance this leak. I think it would be great if you could test the patch and also add some information about the testing scenario. Please note the subject should be "[PATCH v2] mtd: ...", with a proper patch version number. The next patch will be v3 (and so on) which should be stated in the subject. Also... > Signed-off-by: Nilanjan Roychowdhury > --- In this place (between the "---" and the diffstat) you can put some changelog information, like this: Changes from v2: * Did this and that. Changes from v1: * Added check to vfree() in remove function as suggested by Ezequiel. > drivers/mtd/mtdoops.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/drivers/mtd/mtdoops.c b/drivers/mtd/mtdoops.c > index 97bb8f6..4b8b621 100644 > --- a/drivers/mtd/mtdoops.c > +++ b/drivers/mtd/mtdoops.c > @@ -386,6 +386,8 @@ static void mtdoops_notify_remove(struct mtd_info *mtd) > cxt->mtd = NULL; > flush_work(&cxt->work_erase); > flush_work(&cxt->work_write); > + vfree(cxt->oops_page_used); > + cxt->oops_page_used = NULL; > } > > > @@ -439,7 +441,8 @@ static void __exit mtdoops_exit(void) > > unregister_mtd_user(&mtdoops_notifier); > vfree(cxt->oops_buf); > - vfree(cxt->oops_page_used); > + if (cxt->oops_page_used) > + vfree(cxt->oops_page_used); > } > > > -- > 1.7.9.5 > Thanks! -- Ezequiel García, Free Electrons Embedded Linux, Kernel and Android Engineering http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/