From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753520AbcHAXMG (ORCPT ); Mon, 1 Aug 2016 19:12:06 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:46093 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753237AbcHAXLs (ORCPT ); Mon, 1 Aug 2016 19:11:48 -0400 Date: Mon, 1 Aug 2016 16:05:10 -0700 From: Andrew Morton To: zhongjiang Cc: , Subject: Re: [PATCH] fs: fix a bug when new_insert_key is not initialization Message-Id: <20160801160510.4a48a02d68aa5d89a0435b52@linux-foundation.org> In-Reply-To: <1469850669-64815-1-git-send-email-zhongjiang@huawei.com> References: <1469850669-64815-1-git-send-email-zhongjiang@huawei.com> X-Mailer: Sylpheed 3.4.1 (GTK+ 2.24.23; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 30 Jul 2016 11:51:09 +0800 zhongjiang wrote: > From: zhong jiang > > when compile the kenrel code, I happens to the following warn. > fs/reiserfs/ibalance.c:1156:2: warning: ___new_insert_key___ may be used > uninitialized in this function. > memcpy(new_insert_key_addr, &new_insert_key, KEY_SIZE); > > The patch fix it by check the new_insert_ptr. if new_insert_ptr is not > NULL, we ensure that new_insert_key is assigned. therefore, memcpy will > saftly exec the operatetion. > > --- a/fs/reiserfs/ibalance.c > +++ b/fs/reiserfs/ibalance.c > @@ -1153,8 +1153,10 @@ int balance_internal(struct tree_balance *tb, > insert_ptr); > } > > - memcpy(new_insert_key_addr, &new_insert_key, KEY_SIZE); > - insert_ptr[0] = new_insert_ptr; > + if (new_insert_ptr) { > + memcpy(new_insert_key_addr, &new_insert_key, KEY_SIZE); > + insert_ptr[0] = new_insert_ptr; > + } > > return order; Jeff has aleady fixed this with an equivalent patch. It's in -mm at present. From: Jeff Mahoney Subject: reiserfs: fix "new_insert_key may be used uninitialized ..." new_insert_key only makes any sense when it's associated with a new_insert_ptr, which is initialized to NULL and changed to a buffer_head when we also initialize new_insert_key. We can key off of that to avoid the uninitialized warning. Link: http://lkml.kernel.org/r/5eca5ffb-2155-8df2-b4a2-f162f105efed@suse.com Signed-off-by: Jeff Mahoney Cc: Arnd Bergmann Cc: Jan Kara Cc: Linus Torvalds Signed-off-by: Andrew Morton --- fs/reiserfs/ibalance.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff -puN fs/reiserfs/ibalance.c~reiserfs-fix-new_insert_key-may-be-used-uninitialized fs/reiserfs/ibalance.c --- a/fs/reiserfs/ibalance.c~reiserfs-fix-new_insert_key-may-be-used-uninitialized +++ a/fs/reiserfs/ibalance.c @@ -1153,8 +1153,9 @@ int balance_internal(struct tree_balance insert_ptr); } - memcpy(new_insert_key_addr, &new_insert_key, KEY_SIZE); insert_ptr[0] = new_insert_ptr; + if (new_insert_ptr) + memcpy(new_insert_key_addr, &new_insert_key, KEY_SIZE); return order; } _