From patchwork Sun Sep 27 02:54:17 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Brad Harper X-Patchwork-Id: 286915 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=-6.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=no 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 13BBFC2D0A8 for ; Sun, 27 Sep 2020 02:55:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B4004238E6 for ; Sun, 27 Sep 2020 02:55:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="BsgegHhV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729291AbgI0CzF (ORCPT ); Sat, 26 Sep 2020 22:55:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51350 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726478AbgI0CzF (ORCPT ); Sat, 26 Sep 2020 22:55:05 -0400 Received: from mail-pl1-x642.google.com (mail-pl1-x642.google.com [IPv6:2607:f8b0:4864:20::642]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DF405C0613CE; Sat, 26 Sep 2020 19:55:04 -0700 (PDT) Received: by mail-pl1-x642.google.com with SMTP id m15so1469635pls.8; Sat, 26 Sep 2020 19:55:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=CdI7d+rqTIus/Dk9IPQIHfyY4/Pg7193PjaOocT5lDU=; b=BsgegHhV3kefxn2D8GvNrxhp0LxzvLSwSKkojhRVVzWb71cHzJQrp5Cmopy5sYghVw LKs6ZGlZHINXlRyyoW+vB1qtQHcIXfKiNWDpDAYs8npfTxh4FXABfra/r9yRIlEVdRN2 F8Uc7hjz8n4VKGlU462m+IPQdEVtPHqXsWFcbLbdh3SwGASXdn0daDd5usbT17c2JpNs j/OXWCWXWikHzVz1F5xrDDxbBIt+A1Ol9VVpfEBj6xrhKes+0QFk/GyZHk3jhNpoiUyO ESlWSmw/HGHrSHRtEr+Gz44oTd/fmHMjiJV9mwdkklwutPvBtGHsmH+v01LTUHjvsCpM Uwxg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=CdI7d+rqTIus/Dk9IPQIHfyY4/Pg7193PjaOocT5lDU=; b=FRugR8FF124NlXYAN2dmTZ+EygJg6PdzOD2WN+1QmHXSqdmGFFioUKPia7lunC0x0o +AgdPuhnUaOSgKwQF7M2X6i1hsMt/ooaHSN0DDmQ2BaHUlkkkyHvQNO6xT7UCbXJ4Xy9 yodVo5dT6NDDY4qMCkiOfCSVEhBBVsRBQ25MupqhracW489xract2dqu41sBsJ4P8UmZ nhzdfdICGLuAO0Ukcs2tIJ2gpPSea+HkotndA2jG6yY1vN0CcnAnPNlmyPSRVaptPu67 ScnitCK7Spgz/GbWDGEPoBrOL5m9pGf1QzYc2/1VnKI4pImNnbInMfa5Vu7zGOYqh0ZG yktA== X-Gm-Message-State: AOAM5310PQHp2WwWZdKOCT9kZorZUPHdaeVd6EMYxAfm3bkUjPj7wk2L Monyi+u7FbBSOnRiBciwhLw= X-Google-Smtp-Source: ABdhPJy8i2o3+umP00g/fisYoUR9aq+h9qENz1zxtHXrPf0UF0Oc1U9Hi2JEZOQs2ZFMccMPAhQESw== X-Received: by 2002:a17:902:7c8d:b029:d2:80bd:2f30 with SMTP id y13-20020a1709027c8db02900d280bd2f30mr3826797pll.22.1601175304211; Sat, 26 Sep 2020 19:55:04 -0700 (PDT) Received: from buster.buster.your.domain ([2402:b801:2840:8200:21e:6ff:fe42:5032]) by smtp.gmail.com with ESMTPSA id x13sm6685025pfj.199.2020.09.26.19.55.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 26 Sep 2020 19:55:03 -0700 (PDT) From: Brad Harper To: linux-amlogic@lists.infradead.org, linux-mmc@vger.kernel.org Cc: linux-rt-users@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Brad Harper Subject: [PATCH v2 0/1] mmc: host: meson-gx-mmc: fix possible deadlock condition for preempt_rt Date: Sat, 26 Sep 2020 22:54:17 -0400 Message-Id: <20200927025418.12382-1-bjharper@gmail.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org This is a updated experiamental patch for review following discussions with Jerome / Sebastian regarding the usage of threadded interupts in meson-gx-mmc. I don't have a complete understanding or am I a kernel developer but this is my best efforts attempt to address this issue. Also thanks to both of of them for opening up the discussions and Kevin for pointing me in the right direction for patch formatting. Force threaded interrupts for meson_mmc_irq to prevent possible deadlock condition during mmc operations when using preempt_rt with 5.9.0-rc3-rt3 patches on arm64. Using meson-gx-mmc with an emmc device on Hardkernel Odroid N2+ configured with preempt_rt resulted in the soc becoming unresponsive. With lock checking enabled the below inconsistent lock state was observed during boot. After some discussions with tglx in IRC #linux-rt a patch was suggested to remove IRQF_ONESHOT from request_threaded_irq. This has been tested and confirmed by me to resolve both the unresponsive soc and the inconsistent lock state warning when using 5.9.0-rc3-rt3 on arm64 Odroid N2+. Further review and testing is required to ensure there are no adverse impacts or concerns and that is the correct method to resolve the problem. I will continue to test on various amlogic devices with both standard mainline low latency kernel and preempt_rt kernel with -rt patches. Changes since v1: - Add spinlock_t lock to meson_host structure - Add spin_lock_init to driver probe for the host lock to ensure the irq will not attempt to fire again if the threaded irq component is not complete [ 7.858446] ================================ [ 7.858448] WARNING: inconsistent lock state [ 7.858450] 5.9.0-rc3-rt3+ #33 Not tainted [ 7.858453] -------------------------------- [ 7.858456] inconsistent {IN-HARDIRQ-R} -> {HARDIRQ-ON-W} usage. [ 7.858459] swapper/0/1 [HC0[0]:SC0[0]:HE1:SE1] takes: [ 7.858465] ffff80001219f4d8 (&trig->leddev_list_lock){+?.+}-{0:0}, at: led_trigger_set+0x104/0x270 [ 7.858482] {IN-HARDIRQ-R} state was registered at: [ 7.858484] lock_acquire+0xec/0x468 [ 7.858491] rt_read_lock+0xb0/0x108 [ 7.858497] led_trigger_event+0x34/0x88 [ 7.858501] mmc_request_done+0x3f0/0x450 [ 7.858505] meson_mmc_irq+0x284/0x378 [ 7.858511] __handle_irq_event_percpu+0xcc/0x4a8 [ 7.858515] handle_irq_event_percpu+0x60/0xb0 [ 7.858519] handle_irq_event+0x50/0x108 [ 7.858522] handle_fasteoi_irq+0xd0/0x180 [ 7.858527] generic_handle_irq+0x38/0x50 [ 7.858530] __handle_domain_irq+0x6c/0xc8 [ 7.858533] gic_handle_irq+0x5c/0xb8 [ 7.858537] el1_irq+0xbc/0x180 [ 7.858540] arch_cpu_idle+0x28/0x38 [ 7.858544] default_idle_call+0x90/0x3f0 [ 7.858547] do_idle+0x250/0x268 [ 7.858551] cpu_startup_entry+0x2c/0x78 [ 7.858554] rest_init+0x1b0/0x284 [ 7.858559] arch_call_rest_init+0x18/0x24 [ 7.858565] start_kernel+0x550/0x588 [ 7.858569] irq event stamp: 1925495 [ 7.858571] hardirqs last enabled at (1925495): [] _raw_spin_unlock_irqrestore+0xa4/0xb0 [ 7.858576] hardirqs last disabled at (1925494): [] _raw_spin_lock_irqsave+0xa8/0xb8 [ 7.858580] softirqs last enabled at (1857856): [] bdi_register_va+0x114/0x368 [ 7.858586] softirqs last disabled at (1857849): [] bdi_register_va+0x114/0x368 [ 7.858590] other info that might help us debug this: [ 7.858592] Possible unsafe locking scenario: [ 7.858594] CPU0 [ 7.858595] ---- [ 7.858597] lock(&trig->leddev_list_lock); [ 7.858600] [ 7.858602] lock(&trig->leddev_list_lock); [ 7.858604] *** DEADLOCK *** [ 7.858606] 3 locks held by swapper/0/1: [ 7.858609] #0: ffff80001219eb30 (leds_list_lock){++++}-{0:0}, at: led_trigger_register+0xf4/0x1c0 [ 7.858619] #1: ffff0000b0696a70 (&led_cdev->trigger_lock){+.+.}-{0:0}, at: led_trigger_register+0x134/0x1c0 [ 7.858629] #2: ffff800011fb83d0 (rcu_read_lock){....}-{1:2}, at: rt_write_lock+0x8/0x108 [ 7.858637] stack backtrace: [ 7.858640] CPU: 5 PID: 1 Comm: swapper/0 Not tainted 5.9.0-rc3-rt3+ #33 [ 7.858643] Hardware name: Hardkernel ODROID-N2Plus (DT) [ 7.858646] Call trace: [ 7.858647] dump_backtrace+0x0/0x1e8 [ 7.858650] show_stack+0x20/0x30 [ 7.858653] dump_stack+0xf0/0x164 [ 7.858659] print_usage_bug+0x2b4/0x2c0 [ 7.858662] mark_lock+0x2e8/0x360 [ 7.858665] __lock_acquire+0x238/0x1858 [ 7.858669] lock_acquire+0xec/0x468 [ 7.858672] rt_write_lock+0xb0/0x108 [ 7.858675] led_trigger_set+0x104/0x270 [ 7.858678] led_trigger_register+0x180/0x1c0 [ 7.858681] heartbeat_trig_init+0x28/0x5c [ 7.858686] do_one_initcall+0x90/0x4bc [ 7.858690] kernel_init_freeable+0x2cc/0x338 [ 7.858694] kernel_init+0x1c/0x11c [ 7.858697] ret_from_fork+0x10/0x34 Brad Harper (1): mmc: host: meson-gx-mmc: fix possible deadlock condition for preempt_rt drivers/mmc/host/meson-gx-mmc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)