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 X-Spam-Level: X-Spam-Status: No, score=-11.3 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 E26D0C433DF for ; Thu, 16 Jul 2020 05:30:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ADE3F206F4 for ; Thu, 16 Jul 2020 05:30:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="jQND8iLs" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726233AbgGPFaW (ORCPT ); Thu, 16 Jul 2020 01:30:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49034 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726059AbgGPFaV (ORCPT ); Thu, 16 Jul 2020 01:30:21 -0400 Received: from mail-pl1-x643.google.com (mail-pl1-x643.google.com [IPv6:2607:f8b0:4864:20::643]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 38FFEC061755 for ; Wed, 15 Jul 2020 22:30:21 -0700 (PDT) Received: by mail-pl1-x643.google.com with SMTP id k5so3365633plk.13 for ; Wed, 15 Jul 2020 22:30:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:subject:to:cc:references:from:autocrypt:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=vqYp+m7poFYGaCADKhMFMyKYCoivm3CAg0E2XiQB4uA=; b=jQND8iLsyQbPEL6SHrhg+mruO8aswQssHwjWyQSW95RZ2s4ifcXlrhydDwXdGKM+R9 LhEopGUuCmTe9c2El+1a9AgUAI7Ilh/oo4PzXdWj4taO8HdjEHJHP1J4XmKFuD9xCp95 dqQ/9a6p0bbVu9knAUX9nOKqUxmwvhl5Sui/21+zzjyY/PMahgEvAWabiXPVMh96qEFF xuxtSbzPxBmwPzQPFAK78lPRDJeaolvgt88b8RJxTCXtlBR/kIuqfx+LWsaesV9AA08i g2+2M1hkiwTnnzc/MNSOaIB/YUHYlEAD4jlnpBVeKzOFlPYi/LAn3bLruVC3z9hA8exk abxw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:subject:to:cc:references:from:autocrypt :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=vqYp+m7poFYGaCADKhMFMyKYCoivm3CAg0E2XiQB4uA=; b=ZFLs7sjFk9mvUoiYXZ3aIgvdWLWGgXijGlpGLtsSQ3Y5HiqKrIDxRKeYeP9iZdNmEr 1sHdCaACpBHB0dDfI47hdh1AdeKiqAFoPekPgNWUV3l6y8WPikw4JZGK58tCsnSypzTY mOogJc+EmwYo5atXOmctPexN+4Z9blcBOHP/Ld2AU4DS/ms4+rVeQW2gR8DMnhKO6tLf KO2MeG382HmCmoghT+0tUCHB+2ud0DnE2keCI0aUyQmaeS/bBJ6JtF9v3OVounXBfntw 2FhlA5559Q/bNp+0pLBT1mSDO8Ux/10AQ6XcPMEZJx0MOE12UPDHdiYhZ1qDQbmSJbI5 L5VQ== X-Gm-Message-State: AOAM5319zKqCZfU1A27gUgisFB3pnZwO+oUlLYeyK26Ng61T9VaUSGLx b/hu3PidOf9EvEWLodcu65e/89ig X-Google-Smtp-Source: ABdhPJzgolvwUH+q8ytZ+v7JJ3GYHy2m4H/39farjhUARdRU8osnHf2QPy/J2CxmvQCBxIiUpnhNVQ== X-Received: by 2002:a17:902:b78a:: with SMTP id e10mr2344993pls.34.1594877420379; Wed, 15 Jul 2020 22:30:20 -0700 (PDT) Received: from server.roeck-us.net ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id b24sm3757249pgn.8.2020.07.15.22.30.18 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 15 Jul 2020 22:30:19 -0700 (PDT) Subject: Re: [PATCH v1] driver core: Fix scheduling while atomic warnings during device link deletion To: Saravana Kannan , Greg Kroah-Hartman , "Rafael J. Wysocki" Cc: Marek Szyprowski , kernel-team@android.com, linux-kernel@vger.kernel.org References: <20200716050846.2047110-1-saravanak@google.com> From: Guenter Roeck Autocrypt: addr=linux@roeck-us.net; keydata= xsFNBE6H1WcBEACu6jIcw5kZ5dGeJ7E7B2uweQR/4FGxH10/H1O1+ApmcQ9i87XdZQiB9cpN RYHA7RCEK2dh6dDccykQk3bC90xXMPg+O3R+C/SkwcnUak1UZaeK/SwQbq/t0tkMzYDRxfJ7 nyFiKxUehbNF3r9qlJgPqONwX5vJy4/GvDHdddSCxV41P/ejsZ8PykxyJs98UWhF54tGRWFl 7i1xvaDB9lN5WTLRKSO7wICuLiSz5WZHXMkyF4d+/O5ll7yz/o/JxK5vO/sduYDIlFTvBZDh gzaEtNf5tQjsjG4io8E0Yq0ViobLkS2RTNZT8ICq/Jmvl0SpbHRvYwa2DhNsK0YjHFQBB0FX IdhdUEzNefcNcYvqigJpdICoP2e4yJSyflHFO4dr0OrdnGLe1Zi/8Xo/2+M1dSSEt196rXaC kwu2KgIgmkRBb3cp2vIBBIIowU8W3qC1+w+RdMUrZxKGWJ3juwcgveJlzMpMZNyM1jobSXZ0 VHGMNJ3MwXlrEFPXaYJgibcg6brM6wGfX/LBvc/haWw4yO24lT5eitm4UBdIy9pKkKmHHh7s jfZJkB5fWKVdoCv/omy6UyH6ykLOPFugl+hVL2Prf8xrXuZe1CMS7ID9Lc8FaL1ROIN/W8Vk BIsJMaWOhks//7d92Uf3EArDlDShwR2+D+AMon8NULuLBHiEUQARAQABzTJHdWVudGVyIFJv ZWNrIChMaW51eCBhY2NvdW50KSA8bGludXhAcm9lY2stdXMubmV0PsLBgQQTAQIAKwIbAwYL CQgHAwIGFQgCCQoLBBYCAwECHgECF4ACGQEFAlVcphcFCRmg06EACgkQyx8mb86fmYFg0RAA nzXJzuPkLJaOmSIzPAqqnutACchT/meCOgMEpS5oLf6xn5ySZkl23OxuhpMZTVX+49c9pvBx hpvl5bCWFu5qC1jC2eWRYU+aZZE4sxMaAGeWenQJsiG9lP8wkfCJP3ockNu0ZXXAXwIbY1O1 c+l11zQkZw89zNgWgKobKzrDMBFOYtAh0pAInZ9TSn7oA4Ctejouo5wUugmk8MrDtUVXmEA9 7f9fgKYSwl/H7dfKKsS1bDOpyJlqhEAH94BHJdK/b1tzwJCFAXFhMlmlbYEk8kWjcxQgDWMu GAthQzSuAyhqyZwFcOlMCNbAcTSQawSo3B9yM9mHJne5RrAbVz4TWLnEaX8gA5xK3uCNCeyI sqYuzA4OzcMwnnTASvzsGZoYHTFP3DQwf2nzxD6yBGCfwNGIYfS0i8YN8XcBgEcDFMWpOQhT Pu3HeztMnF3HXrc0t7e5rDW9zCh3k2PA6D2NV4fews9KDFhLlTfCVzf0PS1dRVVWM+4jVl6l HRIAgWp+2/f8dx5vPc4Ycp4IsZN0l1h9uT7qm1KTwz+sSl1zOqKD/BpfGNZfLRRxrXthvvY8 BltcuZ4+PGFTcRkMytUbMDFMF9Cjd2W9dXD35PEtvj8wnEyzIos8bbgtLrGTv/SYhmPpahJA l8hPhYvmAvpOmusUUyB30StsHIU2LLccUPPOwU0ETofVZwEQALlLbQeBDTDbwQYrj0gbx3bq 7kpKABxN2MqeuqGr02DpS9883d/t7ontxasXoEz2GTioevvRmllJlPQERVxM8gQoNg22twF7 pB/zsrIjxkE9heE4wYfN1AyzT+AxgYN6f8hVQ7Nrc9XgZZe+8IkuW/Nf64KzNJXnSH4u6nJM J2+Dt274YoFcXR1nG76Q259mKwzbCukKbd6piL+VsT/qBrLhZe9Ivbjq5WMdkQKnP7gYKCAi pNVJC4enWfivZsYupMd9qn7Uv/oCZDYoBTdMSBUblaLMwlcjnPpOYK5rfHvC4opxl+P/Vzyz 6WC2TLkPtKvYvXmdsI6rnEI4Uucg0Au/Ulg7aqqKhzGPIbVaL+U0Wk82nz6hz+WP2ggTrY1w ZlPlRt8WM9w6WfLf2j+PuGklj37m+KvaOEfLsF1v464dSpy1tQVHhhp8LFTxh/6RWkRIR2uF I4v3Xu/k5D0LhaZHpQ4C+xKsQxpTGuYh2tnRaRL14YMW1dlI3HfeB2gj7Yc8XdHh9vkpPyuT nY/ZsFbnvBtiw7GchKKri2gDhRb2QNNDyBnQn5mRFw7CyuFclAksOdV/sdpQnYlYcRQWOUGY HhQ5eqTRZjm9z+qQe/T0HQpmiPTqQcIaG/edgKVTUjITfA7AJMKLQHgp04Vylb+G6jocnQQX JqvvP09whbqrABEBAAHCwWUEGAECAA8CGwwFAlVcpi8FCRmg08MACgkQyx8mb86fmYHNRQ/+ J0OZsBYP4leJvQF8lx9zif+v4ZY/6C9tTcUv/KNAE5leyrD4IKbnV4PnbrVhjq861it/zRQW cFpWQszZyWRwNPWUUz7ejmm9lAwPbr8xWT4qMSA43VKQ7ZCeTQJ4TC8kjqtcbw41SjkjrcTG wF52zFO4bOWyovVAPncvV9eGA/vtnd3xEZXQiSt91kBSqK28yjxAqK/c3G6i7IX2rg6pzgqh hiH3/1qM2M/LSuqAv0Rwrt/k+pZXE+B4Ud42hwmMr0TfhNxG+X7YKvjKC+SjPjqp0CaztQ0H nsDLSLElVROxCd9m8CAUuHplgmR3seYCOrT4jriMFBtKNPtj2EE4DNV4s7k0Zy+6iRQ8G8ng QjsSqYJx8iAR8JRB7Gm2rQOMv8lSRdjva++GT0VLXtHULdlzg8VjDnFZ3lfz5PWEOeIMk7Rj trjv82EZtrhLuLjHRCaG50OOm0hwPSk1J64R8O3HjSLdertmw7eyAYOo4RuWJguYMg5DRnBk WkRwrSuCn7UG+qVWZeKEsFKFOkynOs3pVbcbq1pxbhk3TRWCGRU5JolI4ohy/7JV1TVbjiDI HP/aVnm6NC8of26P40Pg8EdAhajZnHHjA7FrJXsy3cyIGqvg9os4rNkUWmrCfLLsZDHD8FnU mDW4+i+XlNFUPUYMrIKi9joBhu18ssf5i5Q= Message-ID: Date: Wed, 15 Jul 2020 22:30:17 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200716050846.2047110-1-saravanak@google.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/15/20 10:08 PM, Saravana Kannan wrote: > Marek and Guenter reported that commit 287905e68dd2 ("driver core: > Expose device link details in sysfs") caused sleeping/scheduling while > atomic warnings. > > BUG: sleeping function called from invalid context at kernel/locking/mutex.c:935 > in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 12, name: kworker/0:1 > 2 locks held by kworker/0:1/12: > #0: ee8074a8 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x174/0x7dc > #1: ee921f20 ((work_completion)(&sdp->work)){+.+.}-{0:0}, at: process_one_work+0x174/0x7dc > Preemption disabled at: > [] srcu_invoke_callbacks+0xc0/0x154 > ----- 8< ----- SNIP > [] (device_del) from [] (device_unregister+0x24/0x64) > [] (device_unregister) from [] (srcu_invoke_callbacks+0xcc/0x154) > [] (srcu_invoke_callbacks) from [] (process_one_work+0x234/0x7dc) > [] (process_one_work) from [] (worker_thread+0x44/0x51c) > [] (worker_thread) from [] (kthread+0x158/0x1a0) > [] (kthread) from [] (ret_from_fork+0x14/0x20) > Exception stack(0xee921fb0 to 0xee921ff8) > > This was caused by the device link device being released in the context > of srcu_invoke_callbacks(). There is no need to wait till the RCU > callback to release the device link device. So release the device > earlier and revert the RCU callback code to what it was before > commit 287905e68dd2 ("driver core: Expose device link details in sysfs") > > Fixes: 287905e68dd2 ("driver core: Expose device link details in sysfs") > Reported-by: Marek Szyprowski > Reported-by: Guenter Roeck > Signed-off-by: Saravana Kannan > --- > Marek and Guenter, > > It haven't had a chance to test this yet. Can one of you please test it > and confirm it fixes the issue? > With this patch applied, the original warning is gone, but I get lots of other warnings. WARNING: CPU: 0 PID: 1 at drivers/base/core.c:1790 device_release+0x94/0xa4^M Device 'regulators:regulator@0:50038000.ethernet' does not have a release() function, it is broken and must be fixed. WARNING: CPU: 0 PID: 1 at drivers/base/core.c:1790 device_release+0x94/0xa4 Device '53f9c000.gpio:50038000.ethernet' does not have a release() function, it is broken and must be fixed. WARNING: CPU: 0 PID: 1 at drivers/base/core.c:1790 device_release+0x94/0xa4^M Device '50030000.tscadc:50030400.tcq' does not have a release() function, it is broken and must be fixed. and so on. I don't know if this is caused by this patch or by some other patch in -next. Guenter > Thanks, > Saravana > > drivers/base/core.c | 10 +++------- > 1 file changed, 3 insertions(+), 7 deletions(-) > > diff --git a/drivers/base/core.c b/drivers/base/core.c > index 5373ddd029f6..ccb2ce11f5b5 100644 > --- a/drivers/base/core.c > +++ b/drivers/base/core.c > @@ -306,16 +306,10 @@ static struct attribute *devlink_attrs[] = { > }; > ATTRIBUTE_GROUPS(devlink); > > -static void devlink_dev_release(struct device *dev) > -{ > - kfree(to_devlink(dev)); > -} > - > static struct class devlink_class = { > .name = "devlink", > .owner = THIS_MODULE, > .dev_groups = devlink_groups, > - .dev_release = devlink_dev_release, > }; > > static int devlink_add_symlinks(struct device *dev, > @@ -737,7 +731,7 @@ static void device_link_free(struct device_link *link) > > put_device(link->consumer); > put_device(link->supplier); > - device_unregister(&link->link_dev); > + kfree(link); > } > > #ifdef CONFIG_SRCU > @@ -756,6 +750,7 @@ static void __device_link_del(struct kref *kref) > if (link->flags & DL_FLAG_PM_RUNTIME) > pm_runtime_drop_link(link->consumer); > > + device_unregister(&link->link_dev); > list_del_rcu(&link->s_node); > list_del_rcu(&link->c_node); > call_srcu(&device_links_srcu, &link->rcu_head, __device_link_free_srcu); > @@ -771,6 +766,7 @@ static void __device_link_del(struct kref *kref) > if (link->flags & DL_FLAG_PM_RUNTIME) > pm_runtime_drop_link(link->consumer); > > + device_unregister(&link->link_dev); > list_del(&link->s_node); > list_del(&link->c_node); > device_link_free(link); >