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 9CED1C433F5 for ; Mon, 25 Apr 2022 10:15:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238066AbiDYKSt (ORCPT ); Mon, 25 Apr 2022 06:18:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46810 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237682AbiDYKSf (ORCPT ); Mon, 25 Apr 2022 06:18:35 -0400 Received: from mail-ed1-x52c.google.com (mail-ed1-x52c.google.com [IPv6:2a00:1450:4864:20::52c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E554835AA3 for ; Mon, 25 Apr 2022 03:15:29 -0700 (PDT) Received: by mail-ed1-x52c.google.com with SMTP id d6so12674489ede.8 for ; Mon, 25 Apr 2022 03:15:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bgdev-pl.20210112.gappssmtp.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=ZUseZCfMKifoEa5D6gPAjOPxAmseKNfZjI+ANN1hWKA=; b=xN1mcgLdS8Dsbu4fb0NAWfjb5zQSOZomJvqSm7qIYj0sSJ83Uu4Tn/rSivmqLDxE0q +sVA6jVhEnFHdHekhGKcfJ+uOxnkgPK/cUjEjZ84oL3augNVhysnRLXA0+UwZhGOxyOl bmHp9OAEQIvrLAJqiW+kWFFw8IR0lqVwbtLtMDX+UQKrGG/wN9HCPBVanEEZ87kCRmp+ yT/tsJrN4Cjj1cfy1VPfFPodyiOUK0fJr/lEMg0y+VkocAMVecRZCUMfYMGWZnAW7Cr0 byFgw2UHxfDOdNCEeYR7zGgZxIpmrqzmbVaqjQEQU6QvSqVddvRBRTeEyTV8RF6v293h fdSw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=ZUseZCfMKifoEa5D6gPAjOPxAmseKNfZjI+ANN1hWKA=; b=BJpAT3GOVOicoGzkAWY8fWUi43GEq3i4UEiqU3n1LBAot40XGNYvPWy5xVNcexnfI8 uhUZol+mjxSXfoOSYGzLxOQ+LJn2o0cjvH+HIxNxppLEKsNVr8Zuw04Ak/BlC1dzfh6l GcrawLLvuFD08YMQUZF9Bt7JIRv8UIV+p/J5PGwLKwK6MmmjUmAT7DIrUovptMROHfOz lzUP5AzR2xK4fXKYGHBdLiH9AKuIeIVFS20LhoAePLcALVfzHPjJch03AX10kjxxF/dn 4Ivw+EkQcqJz0gI9oaJWVLb12vh1FA0CD3zndz3cRFLTvp03neOgKd0oAHEtxxnUUeAA PFzg== X-Gm-Message-State: AOAM530MGW86lkR6ZA/yx0Fr2h7IMWBwa+xLCEkVZGDSx7qpw/v8BCYZ f7nZiDUXdXtdF8SESufiBsqz4icGMVn8Aahmr0tZByMG0KwIug== X-Google-Smtp-Source: ABdhPJwLTBx4/Q88g+QHH0yd1sat4fNWvOXd8gjHc5E2PIUHyeEUX0480EWsccm5/7ZCUqbcQHURieCwOjJN1RBqblk= X-Received: by 2002:a05:6402:5286:b0:425:f0fb:5d23 with SMTP id en6-20020a056402528600b00425f0fb5d23mr1680469edb.243.1650881728489; Mon, 25 Apr 2022 03:15:28 -0700 (PDT) MIME-Version: 1.0 References: <20220419012810.88417-1-schspa@gmail.com> In-Reply-To: <20220419012810.88417-1-schspa@gmail.com> From: Bartosz Golaszewski Date: Mon, 25 Apr 2022 12:15:17 +0200 Message-ID: Subject: Re: [PATCH v3] gpio: use raw spinlock for gpio chip shadowed data To: Schspa Shi Cc: Andy Shevchenko , Linus Walleij , Florian Fainelli , Serge Semin , Hoan Tran , Linux ARM , "open list:GPIO SUBSYSTEM" , Linux Kernel Mailing List , Doug Berger Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 19, 2022 at 3:28 AM Schspa Shi wrote: > > In case of PREEMPT_RT, there is a raw_spinlock -> spinlock dependency > as the lockdep report shows. > > __irq_set_handler > irq_get_desc_buslock > __irq_get_desc_lock > raw_spin_lock_irqsave(&desc->lock, *flags); // raw spinlock get here > __irq_do_set_handler > mask_ack_irq > dwapb_irq_ack > spin_lock_irqsave(&gc->bgpio_lock, flags); // sleep able spinlock > irq_put_desc_busunlock > > Replace with a raw lock to avoid BUGs. This lock is only used to access > registers, and It's safe to replace with the raw lock without bad > influence. > > [ 15.090359][ T1] ============================= > [ 15.090365][ T1] [ BUG: Invalid wait context ] > [ 15.090373][ T1] 5.10.59-rt52-00983-g186a6841c682-dirty #3 Not tainted > [ 15.090386][ T1] ----------------------------- > [ 15.090392][ T1] swapper/0/1 is trying to lock: > [ 15.090402][ T1] 70ff00018507c188 (&gc->bgpio_lock){....}-{3:3}, at: _raw_spin_lock_irqsave+0x1c/0x28 > [ 15.090470][ T1] other info that might help us debug this: > [ 15.090477][ T1] context-{5:5} > [ 15.090485][ T1] 3 locks held by swapper/0/1: > [ 15.090497][ T1] #0: c2ff0001816de1a0 (&dev->mutex){....}-{4:4}, at: __device_driver_lock+0x98/0x104 > [ 15.090553][ T1] #1: ffff90001485b4b8 (irq_domain_mutex){+.+.}-{4:4}, at: irq_domain_associate+0xbc/0x6d4 > [ 15.090606][ T1] #2: 4bff000185d7a8e0 (lock_class){....}-{2:2}, at: _raw_spin_lock_irqsave+0x1c/0x28 > [ 15.090654][ T1] stack backtrace: > [ 15.090661][ T1] CPU: 4 PID: 1 Comm: swapper/0 Not tainted 5.10.59-rt52-00983-g186a6841c682-dirty #3 > [ 15.090682][ T1] Hardware name: Horizon Robotics Journey 5 DVB (DT) > [ 15.090692][ T1] Call trace: > ...... > [ 15.090811][ T1] _raw_spin_lock_irqsave+0x1c/0x28 > [ 15.090828][ T1] dwapb_irq_ack+0xb4/0x300 > [ 15.090846][ T1] __irq_do_set_handler+0x494/0xb2c > [ 15.090864][ T1] __irq_set_handler+0x74/0x114 > [ 15.090881][ T1] irq_set_chip_and_handler_name+0x44/0x58 > [ 15.090900][ T1] gpiochip_irq_map+0x210/0x644 > > Signed-off-by: Schspa Shi > > --- Applied, thanks! Bart