From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id 093606B0253 for ; Mon, 1 Aug 2016 22:27:35 -0400 (EDT) Received: by mail-pf0-f198.google.com with SMTP id o124so308660074pfg.1 for ; Mon, 01 Aug 2016 19:27:35 -0700 (PDT) Received: from szxga02-in.huawei.com (szxga02-in.huawei.com. [119.145.14.65]) by mx.google.com with ESMTPS id r8si282223pax.279.2016.08.01.19.27.31 for (version=TLS1 cipher=AES128-SHA bits=128/128); Mon, 01 Aug 2016 19:27:34 -0700 (PDT) Message-ID: <57A004C7.10307@huawei.com> Date: Tue, 2 Aug 2016 10:26:15 +0800 From: zhong jiang MIME-Version: 1.0 Subject: Re: [PATCH] fs: fix a bug when new_insert_key is not initialization References: <1469850669-64815-1-git-send-email-zhongjiang@huawei.com> <20160801160510.4a48a02d68aa5d89a0435b52@linux-foundation.org> In-Reply-To: <20160801160510.4a48a02d68aa5d89a0435b52@linux-foundation.org> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org On 2016/8/2 7:05, Andrew Morton wrote: > 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; > } > _ > > > . > ok , I did not notice. thanks. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org