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=-5.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 69B4DC433E6 for ; Tue, 16 Mar 2021 14:33:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 384436507B for ; Tue, 16 Mar 2021 14:33:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235389AbhCPOdT (ORCPT ); Tue, 16 Mar 2021 10:33:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52054 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235321AbhCPOcq (ORCPT ); Tue, 16 Mar 2021 10:32:46 -0400 Received: from mail-il1-x132.google.com (mail-il1-x132.google.com [IPv6:2607:f8b0:4864:20::132]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2AA18C06174A for ; Tue, 16 Mar 2021 07:32:46 -0700 (PDT) Received: by mail-il1-x132.google.com with SMTP id e7so12835673ile.7 for ; Tue, 16 Mar 2021 07:32:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=AIXKXn4V6KkoJZ6335EhpGbuiRlD0jFB/a1rrupY8QM=; b=cS1JmGn2rJptT7YQqIPEEOI22LChvn9/DXBR5sv6XUdPsVLnxaBVrLAld78wHmFJty pP1yYsm98NhR5taOI6AwDi+LZvKNNTpZgn1LnC72j0z7wz8MPLtH3kgvHRnmFkwYbpfg PhmVY7BnxVmwY0yKETWF2UtqyGp+C7VWLGrNVuE0gJSTeqWAV8tlEyZZVIJ13oo3vemZ BrgbA5+FBgDbaiBDYWJsFPv7i9RQWvtHg5d5cEZ9JY/ctFzaUNoXMjK/jwyHvhcKvNlT 29FGUC0OZ508cPKL4HOZ695yznjPlnwWBNys5f49Fg6dCIRer9riCUVzYPFdbl2KWld4 1QIQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=AIXKXn4V6KkoJZ6335EhpGbuiRlD0jFB/a1rrupY8QM=; b=Vgew2Up7Gqagjmn7N8WaUx76Jly2suMwfhsDda/NXtms2aS/o1lvX6XdEg9ypusk95 a9dQ3IKD1dwTmBWDf7Cwedb50yNrZJSPIAAyx6DkswJF7aOUVCSdcrE/kXYv+ktiM/rb 8WBs/Rq7QChA86rLkMHHtwgHXCpg4NIDnzizBuqaH90jHNrK67bjtDobSQNVrlVzWsky 68IdOCq3iGl4kWTkH8SYFhrTdKRNNbjRt33Hho5TU6s+bpH6w1/Wma93PVyyIIGkv/ok t1DZnLuoXBODEFhJqcuvq9skhDnkDqIE6aBzIBRLX5yWAM8wvEvnjhcdl4gnmGBSLTv5 0Wqw== X-Gm-Message-State: AOAM533FDc5fbXC3bvze/r+T6PvDtY/EX1/HOwoinl0K0jZXQqqTUJya PVqsVA+BAv8eCOgwTI9xdapFow== X-Google-Smtp-Source: ABdhPJxl4tkgFxLgyMgFP9Z257Azxecrh39URoO9Ci+5LcDSRsR4IX+GtbDUC53HzZqFnsVW2kRrfA== X-Received: by 2002:a05:6e02:968:: with SMTP id q8mr4215049ilt.31.1615905165655; Tue, 16 Mar 2021 07:32:45 -0700 (PDT) Received: from [192.168.1.30] ([65.144.74.34]) by smtp.gmail.com with ESMTPSA id k10sm8593938iop.42.2021.03.16.07.32.45 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 16 Mar 2021 07:32:45 -0700 (PDT) Subject: Re: [PATCH] sbitmap: Fix sbitmap_put() To: Bart Van Assche Cc: linux-block@vger.kernel.org, Christoph Hellwig , Ming Lei , Hannes Reinecke , Omar Sandoval References: <20210316035420.2584-1-bvanassche@acm.org> From: Jens Axboe Message-ID: Date: Tue, 16 Mar 2021 08:32:44 -0600 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: <20210316035420.2584-1-bvanassche@acm.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 3/15/21 9:54 PM, Bart Van Assche wrote: > This patch fixes the following kernel warning: > > BUG: using smp_processor_id() in preemptible [00000000] code: scsi_eh_0/152 > caller is debug_smp_processor_id+0x17/0x20 > CPU: 1 PID: 152 Comm: scsi_eh_0 Tainted: G W 5.12.0-rc1-dbg+ #6 > Call Trace: > show_stack+0x52/0x58 > dump_stack+0xaf/0xf3 > check_preemption_disabled+0xce/0xd0 > debug_smp_processor_id+0x17/0x20 > scsi_device_unbusy+0x13a/0x1c0 [scsi_mod] > scsi_finish_command+0x4d/0x290 [scsi_mod] > scsi_eh_flush_done_q+0x1e7/0x280 [scsi_mod] > ata_scsi_port_error_handler+0x592/0x750 [libata] > ata_scsi_error+0x1a0/0x1f0 [libata] > scsi_error_handler+0x19e/0x330 [scsi_mod] > kthread+0x222/0x250 > ret_from_fork+0x1f/0x30 It'd be nice to have a bit of a description in here on what is being fixed, eg that we're preemptible and cannot safely use this_cpu_ptr(), and why that it's OK to use raw_cpu_ptr() instead for this particular application. -- Jens Axboe