From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933454AbaJVMwM (ORCPT ); Wed, 22 Oct 2014 08:52:12 -0400 Received: from cantor2.suse.de ([195.135.220.15]:38915 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933049AbaJVMwK (ORCPT ); Wed, 22 Oct 2014 08:52:10 -0400 From: Jan Kara To: Andrew Morton Cc: linux-kernel@vger.kernel.org, Jan Kara , Rasmus Villemoes , stable@vger.kernel.org Subject: [PATCH] bitmap: Fix undefined shift in __bitmap_shift_{left|right}() Date: Wed, 22 Oct 2014 14:51:45 +0200 Message-Id: <1413982305-7272-1-git-send-email-jack@suse.cz> X-Mailer: git-send-email 1.8.1.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If __bitmap_shift_left() or __bitmap_shift_right() are asked to shift by a multiple of BITS_PER_LONG, they will try to shift a long value by BITS_PER_LONG bits which is undefined. Change the functions to avoid the undefined shift. Coverity-id: 1192175 Coverity-id: 1192174 CC: Rasmus Villemoes CC: stable@vger.kernel.org Signed-off-by: Jan Kara --- lib/bitmap.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/lib/bitmap.c b/lib/bitmap.c index cd250a2e14cb..b499ab6ada29 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -131,7 +131,9 @@ void __bitmap_shift_right(unsigned long *dst, lower = src[off + k]; if (left && off + k == lim - 1) lower &= mask; - dst[k] = upper << (BITS_PER_LONG - rem) | lower >> rem; + dst[k] = lower >> rem; + if (rem) + dst[k] |= upper << (BITS_PER_LONG - rem); if (left && k == lim - 1) dst[k] &= mask; } @@ -172,7 +174,9 @@ 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