Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jan Kara , Rasmus Villemoes , Andrew Morton , Linus Torvalds Subject: [PATCH 3.17 245/319] lib/bitmap.c: fix undefined shift in __bitmap_shift_{left|right}() Date: Wed, 12 Nov 2014 10:16:23 +0900 Message-Id: <20141112011033.376535769@linuxfoundation.org> In-Reply-To: <20141112010952.553519040@linuxfoundation.org> References: <20141112010952.553519040@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.17-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jan Kara 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: Greg Kroah-Hartman --- lib/bitmap.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -131,7 +131,9 @@ void __bitmap_shift_right(unsigned long 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 * 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; }