Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757912Ab3JJPyg (ORCPT ); Thu, 10 Oct 2013 11:54:36 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:53046 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755997Ab3JJPu1 (ORCPT ); Thu, 10 Oct 2013 11:50:27 -0400 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Anatol Pomozov , Jens Axboe , Kamal Mostafa Subject: [PATCH 030/104] cfq: explicitly use 64bit divide operation for 64bit arguments Date: Thu, 10 Oct 2013 08:41:18 -0700 Message-Id: <1381419752-29733-31-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1381419752-29733-1-git-send-email-kamal@canonical.com> References: <1381419752-29733-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1354 Lines: 44 3.8.13.11 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Anatol Pomozov commit f3cff25f05f2ac29b2ee355e611b0657482f6f1d upstream. 'samples' is 64bit operant, but do_div() second parameter is 32. do_div silently truncates high 32 bits and calculated result is invalid. In case if low 32bit of 'samples' are zeros then do_div() produces kernel crash. Signed-off-by: Anatol Pomozov Acked-by: Tejun Heo Signed-off-by: Jens Axboe Signed-off-by: Kamal Mostafa --- block/cfq-iosched.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index e62e920..1a872282 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -1484,7 +1484,7 @@ static u64 cfqg_prfill_avg_queue_size(struct seq_file *sf, if (samples) { v = blkg_stat_read(&cfqg->stats.avg_queue_size_sum); - do_div(v, samples); + v = div64_u64(v, samples); } __blkg_prfill_u64(sf, pd, v); return 0; -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/