From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933452AbaJVMsc (ORCPT ); Wed, 22 Oct 2014 08:48:32 -0400 Received: from cantor2.suse.de ([195.135.220.15]:38846 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933049AbaJVMsb (ORCPT ); Wed, 22 Oct 2014 08:48:31 -0400 Date: Wed, 22 Oct 2014 14:48:29 +0200 From: Jan Kara To: Andrew Morton Cc: linux-kernel@vger.kernel.org, Jan Kara , Rasmus Villemoes , stable@vger.kernel.org Subject: Re: [PATCH] bitmap: Fix undefined shift in __bitmap_shift_left() Message-ID: <20141022124829.GA7041@quack.suse.cz> References: <1413981831-6902-1-git-send-email-jack@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1413981831-6902-1-git-send-email-jack@suse.cz> 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 On Wed 22-10-14 14:43:51, Jan Kara wrote: > It __bitmap_shift_left() is asked to shift by a multiple of > BITS_PER_LONG, it will try to shift a long value by BITS_PER_LONG bits > which is undefined. Change the function to take this into account. > > Coverity-id: 1192175 > CC: Rasmus Villemoes > CC: stable@vger.kernel.org > Signed-off-by: Jan Kara Oops, there's one more occurence of this. I'll send an updated patch. Honza > --- > lib/bitmap.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/lib/bitmap.c b/lib/bitmap.c > index cd250a2e14cb..02a8a439fcc7 100644 > --- a/lib/bitmap.c > +++ b/lib/bitmap.c > @@ -172,7 +172,9 @@ void __bitmap_shift_left(unsigned long *dst, > upper = src[k]; > if (left && k == lim - 1) > upper &= (1UL << left) - 1; > - dst[k + off] = lower >> (BITS_PER_LONG - rem) | upper << rem; > + dst[k + off] = upper << rem; > + if (rem) > + dst[k + off] |= lower >> (BITS_PER_LONG - rem); > if (left && k + off == lim - 1) > dst[k + off] &= (1UL << left) - 1; > } > -- > 1.8.1.4 > -- Jan Kara SUSE Labs, CR