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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EFF03C433FE for ; Fri, 15 Oct 2021 17:54:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CB17B60F41 for ; Fri, 15 Oct 2021 17:54:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242354AbhJOR4s (ORCPT ); Fri, 15 Oct 2021 13:56:48 -0400 Received: from mail-pg1-f171.google.com ([209.85.215.171]:40912 "EHLO mail-pg1-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242303AbhJOR4q (ORCPT ); Fri, 15 Oct 2021 13:56:46 -0400 Received: by mail-pg1-f171.google.com with SMTP id q5so9234019pgr.7; Fri, 15 Oct 2021 10:54:40 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=uR9uz/OLZele/hv90GFPXJReAhLyZUOecNTgoswKJTo=; b=OikXIrEWy11MzZfeU2gXfI9GMF3TAE8x0do2OdDSPweM7O9dJk7ZGxMo27Jw1NrhVk oZ6mZtSvoFq8MB5sGw8PwS8tvkiO2GTYV+pvNSL07h7lhAfYUVPNIVfe8rf0988+/PBe AWbExGGmEdefYbGOWEDHH8z9jxZbqAoHfZQ6K7blzqniR4weYjC4ApVYkgZKShQWyAJN jNaMpaiKZKYzn7OLgUsSu99dZ5F8SRdptOLSvONb8rUzeH7+CcBYdVIQPEST1tJF7xTT NZAyVK7sW9yjcCXVSQKgIzu6tjz2AqnRIUlCXdPD8ww4PPee9jlc/hH5GnQMlSG+JHom Qzew== X-Gm-Message-State: AOAM532sYny7hN+cfFal1Ujq5Ay0IxptJtikw/JwYmU7NDNzfNOLFaNo fuWQaS1e1GBmCemNxyecyojB7xfNdlQ= X-Google-Smtp-Source: ABdhPJzl6ayTJdtiiPH0GTkLc6dA9jF/TVYxeu3wirUyYx4iT6g+5fgvZVrqzcyBQ9mdvRXCJ71mSA== X-Received: by 2002:a63:fc65:: with SMTP id r37mr10273633pgk.28.1634320479541; Fri, 15 Oct 2021 10:54:39 -0700 (PDT) Received: from ?IPV6:2601:647:4000:d7:cbb9:9363:2c17:8891? ([2601:647:4000:d7:cbb9:9363:2c17:8891]) by smtp.gmail.com with ESMTPSA id u193sm5116561pgc.34.2021.10.15.10.54.37 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 15 Oct 2021 10:54:38 -0700 (PDT) Message-ID: Date: Fri, 15 Oct 2021 10:54:36 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.1.2 Subject: Re: [PATCH] scsi: sd: fix crashes in sd_resume_runtime Content-Language: en-US To: Miles Chen , "James E . J . Bottomley" , "Martin K . Petersen" , Matthias Brugger , Martin Kepplinger Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, wsd_upstream@mediatek.com, Stanley Chu References: <20211015074654.19615-1-miles.chen@mediatek.com> From: Bart Van Assche In-Reply-To: <20211015074654.19615-1-miles.chen@mediatek.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/15/21 00:46, Miles Chen wrote: > Crash: > [ 4.695171][ T151] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008 > [ 4.710577][ T151] Internal error: Oops: 96000005 [#1] PREEMPT SMP > [ 4.856708][ T151] die+0x16c/0x59c > [ 4.857191][ T151] __do_kernel_fault+0x1e8/0x210 > [ 4.857833][ T151] do_page_fault+0xa4/0x654 > [ 4.858418][ T151] do_translation_fault+0x6c/0x1b0 > [ 4.859083][ T151] do_mem_abort+0x68/0x10c > [ 4.859655][ T151] el1_abort+0x40/0x64 > [ 4.860182][ T151] el1h_64_sync_handler+0x54/0x88 > [ 4.860834][ T151] el1h_64_sync+0x7c/0x80 > [ 4.861395][ T151] sd_resume_runtime+0x20/0x14c > [ 4.862025][ T151] scsi_runtime_resume+0x84/0xe4 > [ 4.862667][ T151] __rpm_callback+0x1f4/0x8cc > [ 4.863275][ T151] rpm_resume+0x7e8/0xaa4 > [ 4.863836][ T151] __pm_runtime_resume+0xa0/0x110 > [ 4.864489][ T151] sd_probe+0x30/0x428 > [ 4.865016][ T151] really_probe+0x14c/0x500 > [ 4.865602][ T151] __driver_probe_device+0xb4/0x18c > [ 4.866278][ T151] driver_probe_device+0x60/0x2c4 > [ 4.866931][ T151] __device_attach_driver+0x228/0x2bc > [ 4.867630][ T151] __device_attach_async_helper+0x154/0x21c > [ 4.868398][ T151] async_run_entry_fn+0x5c/0x1c4 > [ 4.869038][ T151] process_one_work+0x3ac/0x590 > [ 4.869670][ T151] worker_thread+0x320/0x758 > [ 4.870265][ T151] kthread+0x2e8/0x35c > [ 4.870792][ T151] ret_from_fork+0x10/0x20 > > Cc: Stanley Chu > Fixes: ed4246d37f3b ("scsi: sd: REQUEST SENSE for BLIST_IGN_MEDIA_CHANGE devices in runtime_resume()") > Signed-off-by: Miles Chen > --- > drivers/scsi/sd.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c > index 523bf2fdc253..fce63335084e 100644 > --- a/drivers/scsi/sd.c > +++ b/drivers/scsi/sd.c > @@ -3683,7 +3683,12 @@ static int sd_resume(struct device *dev) > static int sd_resume_runtime(struct device *dev) > { > struct scsi_disk *sdkp = dev_get_drvdata(dev); > - struct scsi_device *sdp = sdkp->device; > + struct scsi_device *sdp; > + > + if (!sdkp) /* E.g.: runtime resume at the start of sd_probe() */ > + return 0; > + > + sdp = sdkp->device; > > if (sdp->ignore_media_change) { > /* clear the device's sense data */ Fixing this crash by adding a check inside sd_resume_runtime() seems wrong to me. sd_probe() namely calls dev_set_drvdata(dev, sdkp) before sd_probe() has finished so even with the above patch applied sd_resume() can be called before sd_probe() has finished. With which kernel version has this crash been encountered? The scsi_autopm_get_device() / scsi_autopm_put_device() pair added by commit 6fe8c1dbefd6 ("scsi: balance out autopm get/put calls in scsi_sysfs_add_sdev()"; kernel v3.18) should be sufficient to prevent the reported crash. Thanks, Bart.