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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 99A53CCA485 for ; Mon, 27 Jun 2022 11:43:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237023AbiF0Ln0 (ORCPT ); Mon, 27 Jun 2022 07:43:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43378 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237449AbiF0Lmw (ORCPT ); Mon, 27 Jun 2022 07:42:52 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 72921B3D; Mon, 27 Jun 2022 04:38:12 -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 22D0FB81126; Mon, 27 Jun 2022 11:38:11 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D28C8C3411D; Mon, 27 Jun 2022 11:38:08 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="U0NsycCg" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1656329886; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=mmtDk5vsnneok1FhZ42DmbNlIYBF/ihqmYi8OhtCQUY=; b=U0NsycCgDgx26b01Ari7PRQQoXt8/B+eTA+YCnKjtdJUToEpj1zNY2Mzkeyp/T+kLjQaf+ gQI/MrDZLWJZXXbPLBjqAfAgq9SKxMf13Cy2CXo4oPDsduPse0pvc/IuSfEtdyjIgZtSF4 ceMnMCMoRPs0fWcBb5B2xnyxxUr0vIs= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 2ea245f1 (TLSv1.3:AEAD-AES256-GCM-SHA384:256:NO); Mon, 27 Jun 2022 11:38:06 +0000 (UTC) From: "Jason A. Donenfeld" To: linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org, =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= Cc: "Jason A. Donenfeld" , Gregory Erwin , Kalle Valo , Rui Salvaterra , Herbert Xu , stable@vger.kernel.org Subject: [PATCH v5] ath9k: sleep for less time when unregistering hwrng Date: Mon, 27 Jun 2022 13:37:49 +0200 Message-Id: <20220627113749.564132-1-Jason@zx2c4.com> In-Reply-To: <20220627104955.534013-1-Jason@zx2c4.com> References: <20220627104955.534013-1-Jason@zx2c4.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org Even though hwrng provides a `wait` parameter, it doesn't work very well when waiting for a long time. There are numerous deadlocks that emerge related to shutdown. Work around this API limitation by waiting for a shorter amount of time and erroring more frequently. This commit also prevents hwrng from splatting messages to dmesg when there's a timeout and switches to using schedule_timeout_interruptible(), so that the kthread can be stopped. Reported-by: Gregory Erwin Tested-by: Gregory Erwin Cc: Toke Høiland-Jørgensen Cc: Kalle Valo Cc: Rui Salvaterra Cc: Herbert Xu Cc: stable@vger.kernel.org Fixes: fcd09c90c3c5 ("ath9k: use hw_random API instead of directly dumping into random.c") Link: https://lore.kernel.org/all/CAO+Okf6ZJC5-nTE_EJUGQtd8JiCkiEHytGgDsFGTEjs0c00giw@mail.gmail.com/ Link: https://lore.kernel.org/lkml/CAO+Okf5k+C+SE6pMVfPf-d8MfVPVq4PO7EY8Hys_DVXtent3HA@mail.gmail.com/ Link: https://bugs.archlinux.org/task/75138 Signed-off-by: Jason A. Donenfeld --- Sorry for all the churn here in sending a v4 and v5 so soon. The semantics of schedule_timeout_interruptible vs msleep_interruptible with respect to kthreads is kind of confusing. I'll send a follow up patch for that elsewhere. For now I think this should suffice for fixing the bug. drivers/char/hw_random/core.c | 3 +-- drivers/net/wireless/ath/ath9k/rng.c | 20 +++----------------- 2 files changed, 4 insertions(+), 19 deletions(-) diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c index 16f227b995e8..5309fab98631 100644 --- a/drivers/char/hw_random/core.c +++ b/drivers/char/hw_random/core.c @@ -513,8 +513,7 @@ static int hwrng_fillfn(void *unused) break; if (rc <= 0) { - pr_warn("hwrng: no data available\n"); - msleep_interruptible(10000); + schedule_timeout_interruptible(HZ * 10); continue; } diff --git a/drivers/net/wireless/ath/ath9k/rng.c b/drivers/net/wireless/ath/ath9k/rng.c index cb5414265a9b..757603d1949d 100644 --- a/drivers/net/wireless/ath/ath9k/rng.c +++ b/drivers/net/wireless/ath/ath9k/rng.c @@ -52,20 +52,6 @@ static int ath9k_rng_data_read(struct ath_softc *sc, u32 *buf, u32 buf_size) return j << 2; } -static u32 ath9k_rng_delay_get(u32 fail_stats) -{ - u32 delay; - - if (fail_stats < 100) - delay = 10; - else if (fail_stats < 105) - delay = 1000; - else - delay = 10000; - - return delay; -} - static int ath9k_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) { struct ath_softc *sc = container_of(rng, struct ath_softc, rng_ops); @@ -80,10 +66,10 @@ static int ath9k_rng_read(struct hwrng *rng, void *buf, size_t max, bool wait) bytes_read += max & 3UL; memzero_explicit(&word, sizeof(word)); } - if (!wait || !max || likely(bytes_read) || fail_stats > 110) + if (!wait || !max || likely(bytes_read) || ++fail_stats >= 100 || + ((current->flags & PF_KTHREAD) && kthread_should_stop()) || + schedule_timeout_interruptible(HZ / 20)) break; - - msleep_interruptible(ath9k_rng_delay_get(++fail_stats)); } if (wait && !bytes_read && max) -- 2.35.1