From patchwork Tue Jul 4 21:54:04 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Rokosov X-Patchwork-Id: 700564 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 52083EB64DA for ; Tue, 4 Jul 2023 21:54:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231379AbjGDVyY (ORCPT ); Tue, 4 Jul 2023 17:54:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37296 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230129AbjGDVyX (ORCPT ); Tue, 4 Jul 2023 17:54:23 -0400 Received: from mx1.sberdevices.ru (mx1.sberdevices.ru [37.18.73.165]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9B6F0127; Tue, 4 Jul 2023 14:54:20 -0700 (PDT) Received: from p-infra-ksmg-sc-msk01 (localhost [127.0.0.1]) by mx1.sberdevices.ru (Postfix) with ESMTP id CCAC3100069; Wed, 5 Jul 2023 00:54:17 +0300 (MSK) DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.sberdevices.ru CCAC3100069 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sberdevices.ru; s=mail; t=1688507657; bh=sMHKeng6YabVu1I8dRw/uL0UU93WVerpkNgP4pxZLzY=; h=From:To:Subject:Date:Message-ID:MIME-Version:Content-Type:From; b=rpmRKrpVDesQVijIsKp7PCvkhThX73sNXsYr9+Nsw4vfhGsBqh2cUebtGtW9+V/xh iZ/uoyS4Dn1Ks7wksuOg5KornPBRCCsUi5J7V9TxO+67KsBYWkxxRllRAI0Utm2vKm IpFEXviTHYWMtst4VlDJnlnc/w9y3ME+75l8kQgfHz3FgQHkNln6sUHjbJ3dueBAqc s+h+POjDs1vncnibrvJhxJVCSy9zB2kCClHPc4nhsZK5MmkGwnniQ03BQnvq4eS1XN FeqtCK5zZhlpPt9fJiYQr3KxnnihKgEIp/YF/U1Uoe8/ZotbjzsrYX+VAw/A2o0TOG JA1Y/S/s+7CZw== Received: from p-i-exch-sc-m01.sberdevices.ru (p-i-exch-sc-m01.sberdevices.ru [172.16.192.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.sberdevices.ru (Postfix) with ESMTPS; Wed, 5 Jul 2023 00:54:17 +0300 (MSK) Received: from localhost.localdomain (100.64.160.123) by p-i-exch-sc-m01.sberdevices.ru (172.16.192.107) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.30; Wed, 5 Jul 2023 00:54:04 +0300 From: Dmitry Rokosov To: , , , , , CC: , , , , , , , , Dmitry Rokosov , Jan Dakinevich Subject: [PATCH v2] clk: meson: change usleep_range() to udelay() for atomic context Date: Wed, 5 Jul 2023 00:54:04 +0300 Message-ID: <20230704215404.11533-1-ddrokosov@sberdevices.ru> X-Mailer: git-send-email 2.36.0 MIME-Version: 1.0 X-Originating-IP: [100.64.160.123] X-ClientProxiedBy: p-i-exch-sc-m02.sberdevices.ru (172.16.192.103) To p-i-exch-sc-m01.sberdevices.ru (172.16.192.107) X-KSMG-Rule-ID: 10 X-KSMG-Message-Action: clean X-KSMG-AntiSpam-Lua-Profiles: 178432 [Jul 04 2023] X-KSMG-AntiSpam-Version: 5.9.59.0 X-KSMG-AntiSpam-Envelope-From: DDRokosov@sberdevices.ru X-KSMG-AntiSpam-Rate: 0 X-KSMG-AntiSpam-Status: not_detected X-KSMG-AntiSpam-Method: none X-KSMG-AntiSpam-Auth: dkim=none X-KSMG-AntiSpam-Info: LuaCore: 520 520 ccb018a655251011855942a2571029252d3d69a2, {Tracking_uf_ne_domains}, {Tracking_from_domain_doesnt_match_to}, p-i-exch-sc-m01.sberdevices.ru:7.1.1,5.0.1; sberdevices.ru:7.1.1,5.0.1; lore.kernel.org:7.1.1; 127.0.0.199:7.1.2; d41d8cd98f00b204e9800998ecf8427e.com:7.1.1; 100.64.160.123:7.1.2, FromAlignment: s, {Tracking_white_helo}, ApMailHostAddress: 100.64.160.123 X-MS-Exchange-Organization-SCL: -1 X-KSMG-AntiSpam-Interceptor-Info: scan successful X-KSMG-AntiPhishing: Clean, bases: 2023/07/04 20:47:00 X-KSMG-LinksScanning: Clean, bases: 2023/07/04 20:47:00 X-KSMG-AntiVirus: Kaspersky Secure Mail Gateway, version 2.0.1.6960, bases: 2023/07/04 15:36:00 #21561860 X-KSMG-AntiVirus-Status: Clean, skipped Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org The function meson_clk_pll_enable() can be invoked under the enable_lock spinlock from the clk core logic, which risks a kernel panic during the usleep_range() call: BUG: scheduling while atomic: kworker/u4:2/36/0x00000002 Modules linked in: g_ffs usb_f_fs libcomposite CPU: 1 PID: 36 Comm: kworker/u4:2 Not tainted 6.4.0-rc5 #273 Workqueue: events_unbound async_run_entry_fn Call trace: dump_backtrace+0x9c/0x128 show_stack+0x20/0x38 dump_stack_lvl+0x48/0x60 dump_stack+0x18/0x28 __schedule_bug+0x58/0x78 __schedule+0x828/0xa88 schedule+0x64/0xd8 schedule_hrtimeout_range_clock+0xd0/0x208 schedule_hrtimeout_range+0x1c/0x30 usleep_range_state+0x6c/0xa8 meson_clk_pll_enable+0x1f4/0x310 clk_core_enable+0x78/0x200 clk_core_enable+0x58/0x200 clk_core_enable+0x58/0x200 clk_core_enable+0x58/0x200 clk_enable+0x34/0x60 So it is required to use the udelay() function instead of usleep_range() for the atomic context safety. Fixes: b6ec400aa153 ("clk: meson: introduce new pll power-on sequence for A1 SoC family") Reported-by: Jan Dakinevich Signed-off-by: Dmitry Rokosov --- Changes v2 since v1 at [1]: - remove redundant SoB from commit msg - drop unuseful reference to clk_core_enable() from commit msg Links: [1] https://lore.kernel.org/all/20230703200404.20361-1-ddrokosov@sberdevices.ru/ --- drivers/clk/meson/clk-pll.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/clk/meson/clk-pll.c b/drivers/clk/meson/clk-pll.c index 56ec2210f1ad..eef6f37c8d8d 100644 --- a/drivers/clk/meson/clk-pll.c +++ b/drivers/clk/meson/clk-pll.c @@ -367,9 +367,9 @@ static int meson_clk_pll_enable(struct clk_hw *hw) * 3. enable the lock detect module */ if (MESON_PARM_APPLICABLE(&pll->current_en)) { - usleep_range(10, 20); + udelay(10); meson_parm_write(clk->map, &pll->current_en, 1); - usleep_range(40, 50); + udelay(40); }; if (MESON_PARM_APPLICABLE(&pll->l_detect)) {