From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 616E0C433DB for ; Wed, 30 Dec 2020 21:35:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1FAFF2072E for ; Wed, 30 Dec 2020 21:35:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726214AbgL3Ves (ORCPT ); Wed, 30 Dec 2020 16:34:48 -0500 Received: from relay.sw.ru ([185.231.240.75]:56882 "EHLO relay3.sw.ru" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726197AbgL3Ves (ORCPT ); Wed, 30 Dec 2020 16:34:48 -0500 Received: from [192.168.15.152] by relay3.sw.ru with esmtp (Exim 4.94) (envelope-from ) id 1kuj5h-00ExIG-La; Thu, 31 Dec 2020 00:33:09 +0300 Subject: [PATCH v2] crypto: Fix divide error in do_xor_speed() To: Ard Biesheuvel , Arnd Bergmann , Douglas Anderson Cc: Herbert Xu , "David S. Miller" , Linux Crypto Mailing List , Linux Kernel Mailing List References: <160933061716.928967.463919628731790218.stgit@localhost.localdomain> From: Kirill Tkhai Message-ID: <30381b78-8721-5b4e-e075-300c5af3f9fa@virtuozzo.com> Date: Thu, 31 Dec 2020 00:33:18 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.5.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org crypto: Fix divide error in do_xor_speed() From: Kirill Tkhai Latest (but not only latest) linux-next panics with divide error on my QEMU setup. The patch at the bottom of this message fixes the problem. xor: measuring software checksum speed divide error: 0000 [#1] PREEMPT SMP KASAN PREEMPT SMP KASAN CPU: 3 PID: 1 Comm: swapper/0 Not tainted 5.10.0-next-20201223+ #2177 RIP: 0010:do_xor_speed+0xbb/0xf3 Code: 41 ff cc 75 b5 bf 01 00 00 00 e8 3d 23 8b fe 65 8b 05 f6 49 83 7d 85 c0 75 05 e8 84 70 81 fe b8 00 00 50 c3 31 d2 48 8d 7b 10 f5 41 89 c4 e8 58 07 a2 fe 44 89 63 10 48 8d 7b 08 e8 cb 07 a2 RSP: 0000:ffff888100137dc8 EFLAGS: 00010246 RAX: 00000000c3500000 RBX: ffffffff823f0160 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000808 RDI: ffffffff823f0170 RBP: 0000000000000000 R08: ffffffff8109c50f R09: ffffffff824bb6f7 R10: fffffbfff04976de R11: 0000000000000001 R12: 0000000000000000 R13: ffff888101997000 R14: ffff888101994000 R15: ffffffff823f0178 FS: 0000000000000000(0000) GS:ffff8881f7780000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000000220e000 CR4: 00000000000006a0 Call Trace: calibrate_xor_blocks+0x13c/0x1c4 ? do_xor_speed+0xf3/0xf3 do_one_initcall+0xc1/0x1b7 ? start_kernel+0x373/0x373 ? unpoison_range+0x3a/0x60 kernel_init_freeable+0x1dd/0x238 ? rest_init+0xc6/0xc6 kernel_init+0x8/0x10a ret_from_fork+0x1f/0x30 ---[ end trace 5bd3c1d0b77772da ]--- Fixes: c055e3eae0f1 ("crypto: xor - use ktime for template benchmarking") Signed-off-by: Kirill Tkhai Acked-by: Ard Biesheuvel --- v2: New Year resend :) Added fixes tag. crypto/xor.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/crypto/xor.c b/crypto/xor.c index eacbf4f93990..8f899f898ec9 100644 --- a/crypto/xor.c +++ b/crypto/xor.c @@ -107,6 +107,8 @@ do_xor_speed(struct xor_block_template *tmpl, void *b1, void *b2) preempt_enable(); // bytes/ns == GB/s, multiply by 1000 to get MB/s [not MiB/s] + if (!min) + min = 1; speed = (1000 * REPS * BENCH_SIZE) / (unsigned int)ktime_to_ns(min); tmpl->speed = speed;