From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752715AbbJYCYY (ORCPT ); Sat, 24 Oct 2015 22:24:24 -0400 Received: from m50-135.163.com ([123.125.50.135]:57475 "EHLO m50-135.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752558AbbJYCYW (ORCPT ); Sat, 24 Oct 2015 22:24:22 -0400 Date: Sun, 25 Oct 2015 10:22:32 +0800 From: Geliang Tang To: Kees Cook Cc: Anton Vorontsov , Colin Cross , Tony Luck , linux-kernel@vger.kernel.org, Geliang Tang Subject: Re: [PATCH 1/2] pstore: check PSTORE_FLAGS_FRAGILE in pstore_unregister Message-ID: <20151025022232.GA1181@bogon> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) X-CM-TRANSID: D9GowABXonPoPCxWfpnJEA--.16065S3 X-Coremail-Antispam: 1Uf129KBjvJXoW7CF1xKF1kGF4UZFW7WFy5twb_yoW8Ww1fpr s3G3ZxCr10gF48Xr4UXF4UXFWqkFn5KF4ruryDtw1Iq3WDCr1kKrs0vasxKFyUAr18Cr4I ya1rAa17uFWDZw7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0zRQTmgUUUUU= X-Originating-IP: [116.77.138.30] X-CM-SenderInfo: 5jhoxtpqjwt0rj6rljoofrz/1tbivwqemVWBN5EengAAsA Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 23, 2015 at 09:54:31AM -0700, Kees Cook wrote: > On Fri, Oct 23, 2015 at 7:56 AM, Geliang Tang wrote: > > When PSTORE_FLAGS_FRAGILE flag is set, only kmsg is registered in > > pstore_register. So, under these circumstances, only kmsg needs to > > be unregistered in pstore_unregister. > > > > Signed-off-by: Geliang Tang > > Would it make more sense to have the pstore_unregister_* calls be > defensive, like kfree() is? In other words, it would be safe to call > them, even if they hadn't been registered? > > Either way, I'm fine with this. Good catch! > > -Kees > Thanks for your reply. pstore_unregister_* is defensive as you expected. I have tested it. it is safe to call them if they haven't been registered. This won't cause any trouble. But logically, we should check this flag in pstore_unregister. -Geliang Tang > > --- > > fs/pstore/platform.c | 9 ++++++--- > > 1 file changed, 6 insertions(+), 3 deletions(-) > > > > diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c > > index 0aab920..7ad2038 100644 > > --- a/fs/pstore/platform.c > > +++ b/fs/pstore/platform.c > > @@ -496,9 +496,12 @@ EXPORT_SYMBOL_GPL(pstore_register); > > > > void pstore_unregister(struct pstore_info *psi) > > { > > - pstore_unregister_pmsg(); > > - pstore_unregister_ftrace(); > > - pstore_unregister_console(); > > + if ((psi->flags & PSTORE_FLAGS_FRAGILE) == 0) { > > + pstore_unregister_pmsg(); > > + pstore_unregister_ftrace(); > > + pstore_unregister_console(); > > + } > > + > > pstore_unregister_kmsg(); > > > > free_buf_for_compression(); > > -- > > 2.5.0 > > > > > > > > -- > Kees Cook > Chrome OS Security