From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: ARC-Seal: i=1; a=rsa-sha256; t=1523408458; cv=none; d=google.com; s=arc-20160816; b=LrUOcJ5OF0yKH9EHy/nqfxNHmlbu2fBCXh750/Uo0TPFhVWq6SAHIB24skTStIN1j0 QCr7p8lmzl1zPGJ3Fgfl1+hr4mwJjbRuZbmQWNRpXXT2oaF6WjfMzCiez9LAaIPPzzJc qNkZrnLizif9eTdT4mOSo4pBOecAX7CfBHQD/xf6MRo7MbGSVDAI1ttvvtxD+zNkBYb8 u7cyjwCIiK8eHIQRIPHw+kbZkvjlY5qpPBNxlzd6LPXI3XWO8zz7w1svwcC9HCbGNeP0 kWthDLTJdYQXXRb9fypZs5fUIW6wzLU5P4EF3rSdmH5uKNOnyVYZsioghUIr3b6MeOOk GBig== 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:from:references:cc:to:subject :dkim-signature:arc-authentication-results; bh=wgo6oROl6R5+k6yVmQTX0kXOCldSEzv+lbBgARzDRFo=; b=eqyP67ka8L532bjmRFLKwlP2N+2X2EmlMVia0+7i2c6VXOTSJwOc+K91nIzSslGP+A eie/QexH6s1T/ipLEizdPzxCf1zt+UGn6MzaYYdy41iC5Csk3AB7/cyLW+kXIV+YmzHD OMaLiIQT8PqtM0+auC68xLDZAXmkCdnVu3X5KJUFUSxvUcCXy15F6XUPubZ5aE1oEWDB 9fyUqVj/O0Rz2YXmMoMUUOqVfomkFN8f1EfuFKdFVK7LxQsE53siDl8u/z9iYQt/vHuh U3OJnK3njRIk9L22SH5ZuY8fpONLr8VwSAxlhzDjuIygBxw811/1GVGsEe5vmzYWsxHt 9RmA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=VxQGUjGa; spf=pass (google.com: domain of baijiaju1990@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=baijiaju1990@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b=VxQGUjGa; spf=pass (google.com: domain of baijiaju1990@gmail.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=baijiaju1990@gmail.com; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com X-Google-Smtp-Source: AIpwx4/GQ3epnJ+A18s2sVTEKnZ1rwrq/fgH12ebjhtqDLqlvUkiLAtFHdHD07KK7cU3GZiV+n3yAw== Subject: Re: [PATCH 1/4] xen: xen-pciback: Replace GFP_ATOMIC with GFP_KERNEL in pcistub_probe To: Boris Ostrovsky , 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> <9703e77f-35e8-aa11-9ddb-fdc322efd6d2@oracle.com> From: Jia-Ju Bai Message-ID: <311acb17-1cab-bb1a-b612-23e7523f6709@gmail.com> Date: Wed, 11 Apr 2018 09:00:40 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0 MIME-Version: 1.0 In-Reply-To: <9703e77f-35e8-aa11-9ddb-fdc322efd6d2@oracle.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1597281379484745930?= X-GMAIL-MSGID: =?utf-8?q?1597409548206626031?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On 2018/4/10 23:01, Boris Ostrovsky wrote: > 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? Okay, I will send a patch for it soon. You can have a look :) Best wishes, Jia-Ju Bai