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 37F20C433F5 for ; Mon, 3 Oct 2022 17:49:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229812AbiJCRs7 (ORCPT ); Mon, 3 Oct 2022 13:48:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42642 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229678AbiJCRst (ORCPT ); Mon, 3 Oct 2022 13:48:49 -0400 Received: from mail-qv1-xf31.google.com (mail-qv1-xf31.google.com [IPv6:2607:f8b0:4864:20::f31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8C12E25E82 for ; Mon, 3 Oct 2022 10:48:35 -0700 (PDT) Received: by mail-qv1-xf31.google.com with SMTP id de14so7214566qvb.5 for ; Mon, 03 Oct 2022 10:48:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date; bh=0C6yn+Jn2hn9bHpTYIQGfMQvGSUJwmSgN1JbJ6wT+Qw=; b=UxquGlCPU0Lxr38j5xuVAab5bB4JR6CVnYGjR9TJU5chw7InxO/KyV1T0YpRhUJTtR Tyy3DPu5BGyAcxVWu15wE62nScZBCd01Lf1ycu+7fEc7wt6uJimMG3poD5hyOCoun8LO q1fvJgEDFwQG/5GNmnw1FmaM6to2K3RlolaOswgn72w2g+5GbVBeOnAW+2jmG/o/7rUQ 1F9FYpK6iR7JNBjC9xiOHaVqlL4U7rxCOlz1iAzLZ0GLmnXtertHWZ/Q78d6Kb8yoFM/ l0AQym463rcezixaDAHMg9nvDvYuhjPR+g+hqQnJbUejeNmSERcTx00mQZoCCjSE9yWF Aw8Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date; bh=0C6yn+Jn2hn9bHpTYIQGfMQvGSUJwmSgN1JbJ6wT+Qw=; b=hwsQnZURlKLsdkRsjJ9So79rlcvQg9NSv/vcDlWG01EQDGpUgyV7BJ1h78Elr4pmwx QgLRqql+dk2tdUe/p9n68nv5UePEYHG9090cLJRYWcjRei1lKv5x7ZTvmp00iFA6VmgI fdIBpqOcq0ng7j20PGIGIQfzKe36+FSSp3B005nvDbfIh2WTzU47s/tf2pLIeWs/E92N 6xbZ621oTM++fAP+i/q9uzdbE6qmuBJH2R2yerfgZGWet44E2/7HiOXHIromDbNHCczx Witwzzw224PqhqBEm5XBej2ghyxt6qPTabsG2ld2Dx7GUI7xCkmwSMJLgREUyr4JTr1g I/eQ== X-Gm-Message-State: ACrzQf0uzKJ8iGvB5F89Q1kwMRfEsPhLfGn+oBWDHqwUd5CCQ3pueHaF Je2SkMiaW1sYK19i2Tmqp9Y= X-Google-Smtp-Source: AMsMyM4CoyRnuDtKUgrn9x6v7MJeGrWrZeDtxB0bZfhjyJC5KBwnJKsttLVcbw67Oke1SPssDx7Omg== X-Received: by 2002:ad4:5f48:0:b0:4af:b266:3bbd with SMTP id p8-20020ad45f48000000b004afb2663bbdmr16065477qvg.0.1664819314688; Mon, 03 Oct 2022 10:48:34 -0700 (PDT) Received: from [10.69.46.142] ([192.19.223.252]) by smtp.gmail.com with ESMTPSA id b1-20020ac87541000000b0035bb6c3811asm9895482qtr.53.2022.10.03.10.48.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 03 Oct 2022 10:48:34 -0700 (PDT) Message-ID: <8aeea62b-c947-6414-bca1-3bd3f427cd56@gmail.com> Date: Mon, 3 Oct 2022 10:48:31 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.3.0 Subject: Re: [PATCH] nvme-fc: fix sleep-in-atomic-context bug caused by nvme_fc_rcv_ls_req Content-Language: en-US To: duoming@zju.edu.cn Cc: linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org, james.smart@broadcom.com, kbusch@kernel.org, axboe@fb.com, hch@lst.de, sagi@grimberg.me References: <20221002001909.20070-1-duoming@zju.edu.cn> <305fbf18-6759-9b00-6fc0-93a4a2e40be2@gmail.com> <7bd9e071.1063f1.1839b89cefa.Coremail.duoming@zju.edu.cn> <2f36fa52-2dc3-21f3-b53c-d0a9186c3ceb@gmail.com> From: James Smart In-Reply-To: <2f36fa52-2dc3-21f3-b53c-d0a9186c3ceb@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/2/2022 7:56 PM, James Smart wrote: > On 10/2/2022 6:50 PM, duoming@zju.edu.cn wrote: >> Hello, >> >> On Sun, 2 Oct 2022 10:12:15 -0700 James Smart wrote: >> >>> On 10/1/2022 5:19 PM, Duoming Zhou wrote: >>>> The function lpfc_poll_timeout() is a timer handler that runs in an >>>> atomic context, but it calls "kzalloc(.., GFP_KERNEL)" that may sleep. >>>> As a result, the sleep-in-atomic-context bug will happen. The processes >>>> is shown below: >>>> >>>> lpfc_poll_timeout() >>>>    lpfc_sli_handle_fast_ring_event() >>>>     lpfc_sli_process_unsol_iocb() >>>>      lpfc_complete_unsol_iocb() >>>>       lpfc_nvme_unsol_ls_handler() >>>>        lpfc_nvme_handle_lsreq() >>>>         nvme_fc_rcv_ls_req() >>>>          kzalloc(sizeof(.., GFP_KERNEL) //may sleep >>>> >>>> This patch changes the gfp_t parameter of kzalloc() from GFP_KERNEL to >>>> GFP_ATOMIC in order to mitigate the bug. >>>> >>>> Fixes: 14fd1e98afaf ("nvme-fc: Add Disconnect Association Rcv support") >>>> Signed-off-by: Duoming Zhou >>>> --- >>>>    drivers/nvme/host/fc.c | 2 +- >>>>    1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c >>>> index 127abaf9ba5..36698dfc8b3 100644 >>>> --- a/drivers/nvme/host/fc.c >>>> +++ b/drivers/nvme/host/fc.c >>>> @@ -1754,7 +1754,7 @@ nvme_fc_rcv_ls_req(struct nvme_fc_remote_port >>>> *portptr, >>>>        lsop = kzalloc(sizeof(*lsop) + >>>>                sizeof(union nvmefc_ls_requests) + >>>>                sizeof(union nvmefc_ls_responses), >>>> -            GFP_KERNEL); >>>> +            GFP_ATOMIC); >>>>        if (!lsop) { >>>>            dev_info(lport->dev, >>>>                "RCV %s LS failed: No memory\n", >>> >>> I would prefer this was fixed within lpfc rather than introducing atomic >>> allocations (1st in either host or target transport).  It was introduced >>> by lpfc change in irq handling style. >> >> Thank your for your reply and suggestions! >> >> Do you think change the lpfc_poll_timeout() to a delayed_work is better? >> >> Best regards, >> Duoming Zhou > > as a minimum: the lpfc_complete_unsol_iocb handler should be passing off > the iocb to a work queue routine - so that the context changes so that > either nvme host or nvmet ls callback routines can be called. If > possible, it should do the axchg alloc - to avoid a GFP_ATOMIC there as > well... > > It's usually best for these nvme LS's and ELS's to be done in a slow > path thread/work queue element. That may mean segmenting a little > earlier in the path. > > -- james > looking further... lpfc_poll_timeout() should only be used on an SLI-3 adapter. The existing SLI-3 adapters don't support NVMe. So I'm a little confused by this stack trace. Can you describe what the system config/software setup is and specifically what lpfc adapter is being used (dmesg attachment logs are sufficient, or lspci output). -- james