From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx48dZ/e/JH3tGJGuEIYzYqdWtM+UPfE+2DFQmFYGXD0RoMXyJhUHkqVru3T18ci+OcqFrDTY ARC-Seal: i=1; a=rsa-sha256; t=1523372397; cv=none; d=google.com; s=arc-20160816; b=TjbP0fewVvzCuGpRNlwR3JdW6xwi/k9BNzLkdF0Qwrx1WRmCKRN+LVrENTtlQqcPYK VgygV5K8aLa2oYcdmG2IEuoTXybvLb1pmrZ6mBNeFFEuAjNkCa8CnarrlRZ6jhqhnX8O p3emcKre2O1cRrIAqCLmxBfSN38l8Qi4+tUZPZJSPi1tFs8fxruMmqzcrFfctu/3VBhp NBc9tOsgAFhE3KTB9OYjrhPFJbzbTeYcjYbRfEc5wOmZxHhJNTT5FGUa/Tk/QhsHeawP EiaxA4gibTjanAlbpoa6tJ4HgtMsIJIKTuFvroOe4L3yZ1E2wcmpTdFclNHgxY/s6K+7 LZMA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-language:content-transfer-encoding:in-reply-to:mime-version :user-agent:date:message-id:autocrypt:openpgp:from:references:cc:to :subject:dkim-signature:arc-authentication-results; bh=mvFgOB00QuldECABaOCBOjrRjLo/1rt3DJ0wzSsmOVE=; b=nyROunDxrkd/VczN8xtrWEGUQnLHPYbqnKt0/QYRiiw1bKHI77V0i+kB6ncXiZ8EQz HbnxK5NHkF3Zxnim0ZdkqQAXXo7LzNJtprCEzp5NkK/PBHSGsjhZcXZz5lciUiXUAstt iQfFdWhi83SUZ8B9sBck3qKpEoc+np6G+Lfq+TA4S4cFZ5pZuCf3OZ5LnPXzJkZgVzRx BgXwxDxz2PUz+6CJtBKUPAZzdkiS2QfDCiFPx+pXeSHHhYYCPJ+LYsqK4VTd/tbr+4Ml 4A+cLcngBMExy8KdkbpZLbicASslzyqyG8jjlpwr34x5u9+tvEv33QpmhWmcJFZSyte3 Mr6A== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@oracle.com header.s=corp-2017-10-26 header.b=HxzkUqDi; spf=pass (google.com: domain of boris.ostrovsky@oracle.com designates 141.146.126.78 as permitted sender) smtp.mailfrom=boris.ostrovsky@oracle.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=oracle.com Authentication-Results: mx.google.com; dkim=pass header.i=@oracle.com header.s=corp-2017-10-26 header.b=HxzkUqDi; spf=pass (google.com: domain of boris.ostrovsky@oracle.com designates 141.146.126.78 as permitted sender) smtp.mailfrom=boris.ostrovsky@oracle.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=oracle.com Subject: Re: [PATCH 1/4] xen: xen-pciback: Replace GFP_ATOMIC with GFP_KERNEL in pcistub_probe To: Jia-Ju Bai , jgross@suse.com, gregkh@linuxfoundation.org Cc: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org References: <1523286216-26345-1-git-send-email-baijiaju1990@gmail.com> <74fe5dd3-fb85-bed8-82b6-a9fb7a3a376d@gmail.com> From: Boris Ostrovsky Openpgp: preference=signencrypt Autocrypt: addr=boris.ostrovsky@oracle.com; 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Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <74fe5dd3-fb85-bed8-82b6-a9fb7a3a376d@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=8858 signatures=668698 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1711220000 definitions=main-1804100146 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1597281379484745930?= X-GMAIL-MSGID: =?utf-8?q?1597371735645999839?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On 04/10/2018 10:31 AM, Jia-Ju Bai wrote: > > > > On 2018/4/10 22:27, Boris Ostrovsky wrote: >> On 04/09/2018 11:03 AM, Jia-Ju Bai wrote: >>> pcistub_probe() is never called in atomic context. >>> This function is only set as ".probe" in struct pci_driver. >>> >>> Despite never getting called from atomic context, >>> pcistub_probe() calls kmalloc() with GFP_ATOMIC, >>> which does not sleep for allocation. >>> GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL, >>> which can sleep and improve the possibility of sucessful allocation. >>> >>> This is found by a static analysis tool named DCNS written by myself. >>> And I also manually check it. >>> >>> Signed-off-by: Jia-Ju Bai >> What about use of GFP_ATOMIC in pcistub_reg_add()? > > Thanks for your reply :) > I find pcistub_reg_add() is called by pcistub_quirk_add(). > And pcistub_quirk_add() is called in the macro DRIVER_ATTR(). > I am not sure whether DRIVER_ATTR() can make the function called in > atomic context, > so I do not analyze it in my tool. I don't see why it needs to be ATOMIC, it's sysfs access. Can you send a patch to fix it as well? Thanks. -boris