From patchwork Tue Aug 2 12:56:10 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Jason A. Donenfeld" X-Patchwork-Id: 12934621 X-Patchwork-Delegate: kuba@kernel.org Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BB44CC00140 for ; Tue, 2 Aug 2022 12:56:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236716AbiHBM4c (ORCPT ); Tue, 2 Aug 2022 08:56:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40562 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233153AbiHBM4a (ORCPT ); Tue, 2 Aug 2022 08:56:30 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9B024B7DD for ; Tue, 2 Aug 2022 05:56:29 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 540FAB81EFA for ; Tue, 2 Aug 2022 12:56:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6FFC2C433B5; Tue, 2 Aug 2022 12:56:26 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="WgKgP+IO" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1659444985; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=IBuUm247yyrJEHxfKP62BHIIjounyU4x8Yyk2UEXz4E=; b=WgKgP+IOQ0RM0dkcpANJlQGsAsV1odeMdQDLH4Vk09miHLdVYW3zwVzvJazQSCyHhjeVMx lWnTwNV+9AcAGgqOy7D2G7NbHYJy9ECqots7iGl1WGmdd58ryRVMH097/RYe9O5s6zt5JL dU8pu9qTJmRH5bMzCmC8D8kGgaz4fEc= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 44e7471c (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Tue, 2 Aug 2022 12:56:25 +0000 (UTC) From: "Jason A. Donenfeld" To: kuba@kernel.org, pablo@netfilter.org, netdev@vger.kernel.org Cc: "Jason A. Donenfeld" , Thomas Gleixner Subject: [PATCH next-next 1/4] wireguard: ratelimiter: use hrtimer in selftest Date: Tue, 2 Aug 2022 14:56:10 +0200 Message-Id: <20220802125613.340848-2-Jason@zx2c4.com> In-Reply-To: <20220802125613.340848-1-Jason@zx2c4.com> References: <20220802125613.340848-1-Jason@zx2c4.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org Using msleep() is problematic because it's compared against ratelimiter.c's ktime_get_coarse_boottime_ns(), which means on systems with slow jiffies (such as UML's forced HZ=100), the result is inaccurate. So switch to using schedule_hrtimeout(). However, hrtimer gives us access only to the traditional posix timers, and none of the _COARSE variants. So now, rather than being too imprecise like jiffies, it's too precise. One solution would be to give it a large "range" value, but this will still fire early on a loaded system. A better solution is to align the timeout to the actual coarse timer, and then round up to the nearest tick, plus change. So add the timeout to the current coarse time, and then schedule_hrtimer() until the absolute computed time. This should hopefully reduce flakes in CI as well. Note that we keep the retry loop in case the entire function is running behind, because the test could still be scheduled out, by either the kernel or by the hypervisor's kernel, in which case restarting the test and hoping to not be scheduled out still helps. Fixes: e7096c131e51 ("net: WireGuard secure network tunnel") Suggested-by: Thomas Gleixner Signed-off-by: Jason A. Donenfeld --- drivers/net/wireguard/selftest/ratelimiter.c | 25 +++++++++++--------- kernel/time/hrtimer.c | 1 + 2 files changed, 15 insertions(+), 11 deletions(-) diff --git a/drivers/net/wireguard/selftest/ratelimiter.c b/drivers/net/wireguard/selftest/ratelimiter.c index 007cd4457c5f..ba87d294604f 100644 --- a/drivers/net/wireguard/selftest/ratelimiter.c +++ b/drivers/net/wireguard/selftest/ratelimiter.c @@ -6,28 +6,29 @@ #ifdef DEBUG #include +#include static const struct { bool result; - unsigned int msec_to_sleep_before; + u64 nsec_to_sleep_before; } expected_results[] __initconst = { [0 ... PACKETS_BURSTABLE - 1] = { true, 0 }, [PACKETS_BURSTABLE] = { false, 0 }, - [PACKETS_BURSTABLE + 1] = { true, MSEC_PER_SEC / PACKETS_PER_SECOND }, + [PACKETS_BURSTABLE + 1] = { true, NSEC_PER_SEC / PACKETS_PER_SECOND }, [PACKETS_BURSTABLE + 2] = { false, 0 }, - [PACKETS_BURSTABLE + 3] = { true, (MSEC_PER_SEC / PACKETS_PER_SECOND) * 2 }, + [PACKETS_BURSTABLE + 3] = { true, (NSEC_PER_SEC / PACKETS_PER_SECOND) * 2 }, [PACKETS_BURSTABLE + 4] = { true, 0 }, [PACKETS_BURSTABLE + 5] = { false, 0 } }; static __init unsigned int maximum_jiffies_at_index(int index) { - unsigned int total_msecs = 2 * MSEC_PER_SEC / PACKETS_PER_SECOND / 3; + u64 total_nsecs = 2 * NSEC_PER_SEC / PACKETS_PER_SECOND / 3; int i; for (i = 0; i <= index; ++i) - total_msecs += expected_results[i].msec_to_sleep_before; - return msecs_to_jiffies(total_msecs); + total_nsecs += expected_results[i].nsec_to_sleep_before; + return nsecs_to_jiffies(total_nsecs); } static __init int timings_test(struct sk_buff *skb4, struct iphdr *hdr4, @@ -42,8 +43,12 @@ static __init int timings_test(struct sk_buff *skb4, struct iphdr *hdr4, loop_start_time = jiffies; for (i = 0; i < ARRAY_SIZE(expected_results); ++i) { - if (expected_results[i].msec_to_sleep_before) - msleep(expected_results[i].msec_to_sleep_before); + if (expected_results[i].nsec_to_sleep_before) { + ktime_t timeout = ktime_add(ktime_add_ns(ktime_get_coarse_boottime(), TICK_NSEC * 4 / 3), + ns_to_ktime(expected_results[i].nsec_to_sleep_before)); + set_current_state(TASK_UNINTERRUPTIBLE); + schedule_hrtimeout_range_clock(&timeout, 0, HRTIMER_MODE_ABS, CLOCK_BOOTTIME); + } if (time_is_before_jiffies(loop_start_time + maximum_jiffies_at_index(i))) @@ -127,7 +132,7 @@ bool __init wg_ratelimiter_selftest(void) if (IS_ENABLED(CONFIG_KASAN) || IS_ENABLED(CONFIG_UBSAN)) return true; - BUILD_BUG_ON(MSEC_PER_SEC % PACKETS_PER_SECOND != 0); + BUILD_BUG_ON(NSEC_PER_SEC % PACKETS_PER_SECOND != 0); if (wg_ratelimiter_init()) goto out; @@ -176,7 +181,6 @@ bool __init wg_ratelimiter_selftest(void) test += test_count; goto err; } - msleep(500); continue; } else if (ret < 0) { test += test_count; @@ -195,7 +199,6 @@ bool __init wg_ratelimiter_selftest(void) test += test_count; goto err; } - msleep(50); continue; } test += test_count; diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index 0ea8702eb516..23af5eca11b1 100644 --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -2311,6 +2311,7 @@ schedule_hrtimeout_range_clock(ktime_t *expires, u64 delta, return !t.task ? 0 : -EINTR; } +EXPORT_SYMBOL_GPL(schedule_hrtimeout_range_clock); /** * schedule_hrtimeout_range - sleep until timeout