From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761736AbbA1EoX (ORCPT ); Tue, 27 Jan 2015 23:44:23 -0500 Received: from mail.kernel.org ([198.145.29.136]:40378 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964967AbbA1EXh (ORCPT ); Tue, 27 Jan 2015 23:23:37 -0500 From: lizf@kernel.org To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Jan Kara , Rasmus Villemoes , Andrew Morton , Linus Torvalds , Zefan Li Subject: [PATCH 3.4 114/177] lib/bitmap.c: fix undefined shift in __bitmap_shift_{left|right}() Date: Wed, 28 Jan 2015 12:09:32 +0800 Message-Id: <1422418236-12852-205-git-send-email-lizf@kernel.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1422418050-12581-1-git-send-email-lizf@kernel.org> References: <1422418050-12581-1-git-send-email-lizf@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jan Kara 3.4.106-rc1 review patch. If anyone has any objections, please let me know. ------------------ commit ea5d05b34aca25c066e0699512d0ffbd8ee6ac3e upstream. 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 Signed-off-by: Jan Kara Cc: Rasmus Villemoes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Zefan Li --- lib/bitmap.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/lib/bitmap.c b/lib/bitmap.c index b5a8b6a..6ccf212 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; } -- 1.9.1