From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from dggsgout12.his.huawei.com (dggsgout12.his.huawei.com [45.249.212.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7D3871427A for ; Tue, 30 Dec 2025 02:52:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767063129; cv=none; b=r4gDcjA7rtzPSmGMDWpwPAf3h0iC82zdGp8P2LTK+xiLibG+5pZYO6/zC/drJULhYu2QPeHxluThpwsh7ix8A4AYDr5ovUfyUk/hLIkTFJ9sJzvKmc13WUHZFFHMkAbh458hFI7jervowM6xUfiVhwTcjbwCLFAbcJaGxjpeVlk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767063129; c=relaxed/simple; bh=PcnJPZ51sozxq82KwDewQ45Ixdqqu/YmFo3fA9JNe6E=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=pgjJlBUUGUV1sVM9ROMpHh1rwPzkKNp6ZX1h2v2RiZaC82g/qNDwx99NwnVnuKxJLCzj/d71VuifMXSGfkrjz7KbsqZ97F1rx5lYFJk8Ec8JAmWuJU5iXkkKoHFV9VtH0weTEP6sFcZZRQ+rhXJjvbfMlutMxTOuHY6M35hZkQ4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.170]) by dggsgout12.his.huawei.com (SkyGuard) with ESMTPS id 4dgHfb4NDtzKHMQc for ; Tue, 30 Dec 2025 10:51:35 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.128]) by mail.maildlp.com (Postfix) with ESMTP id 01BCB4056B for ; Tue, 30 Dec 2025 10:52:04 +0800 (CST) Received: from [10.174.178.129] (unknown [10.174.178.129]) by APP4 (Coremail) with SMTP id gCh0CgAXePhSPlNpWTDkBw--.29396S3; Tue, 30 Dec 2025 10:52:03 +0800 (CST) Message-ID: <05a36e03-a1d3-bd2e-1e95-86d71add6a8b@huaweicloud.com> Date: Tue, 30 Dec 2025 10:52:02 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.10.0 Subject: Re: [PATCH] char: lp: Fix NULL pointer dereference of cad To: Al Viro Cc: arnd@arndb.de, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, "wanghai (M)" References: <20251218142019.2822081-1-linan666@huaweicloud.com> <5e81851f-a7f4-5606-9e0d-b823aa5210e5@huaweicloud.com> <20251230021016.GF1712166@ZenIV> From: Li Nan In-Reply-To: <20251230021016.GF1712166@ZenIV> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-CM-TRANSID:gCh0CgAXePhSPlNpWTDkBw--.29396S3 X-Coremail-Antispam: 1UD129KBjvdXoW7JFykAFWUAr4fWFyUAFW3GFg_yoWkWFb_ur W0v3s7Cr9xJw48Ww1DKFZxt39rCF1kZry3J3yjqw4av3yUJF1DXrWvv3s7A3yxWF48JFZ0 krZ8ZryxCwnF9jkaLaAFLSUrUUUUjb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUIcSsGvfJTRUUUb3xYFVCjjxCrM7AC8VAFwI0_Jr0_Gr1l1xkIjI8I6I8E6xAIw20E Y4v20xvaj40_Wr0E3s1l1IIY67AEw4v_Jr0_Jr4l8cAvFVAK0II2c7xJM28CjxkF64kEwV A0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW7JVWDJwA2z4x0Y4vE2Ix0cI8IcVCY1x02 67AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I 0E14v26rxl6s0DM2vYz4IE04k24VAvwVAKI4IrM2AIxVAIcxkEcVAq07x20xvEncxIr21l 5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv67 AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IY64vIr41lc7I2V7IY0VAS07Al zVAYIcxG8wCY1x0262kKe7AKxVWUAVWUtwCF04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7x kEbVWUJVW8JwC20s026c02F40E14v26r1j6r18MI8I3I0E7480Y4vE14v26r106r1rMI8E 67AF67kF1VAFwI0_JF0_Jw1lIxkGc2Ij64vIr41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCw CI42IY6xIIjxv20xvEc7CjxVAFwI0_Jr0_Gr1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1x MIIF0xvEx4A2jsIE14v26r1j6r4UMIIF0xvEx4A2jsIEc7CjxVAFwI0_Jr0_GrUvcSsGvf C2KfnxnUUI43ZEXa7IU8Y0P3UUUUU== X-CM-SenderInfo: polqt0awwwqx5xdzvxpfor3voofrz/ 在 2025/12/30 10:10, Al Viro 写道: > On Tue, Dec 30, 2025 at 09:51:43AM +0800, Li Nan wrote: >> Friendly ping... > >>> @@ -569,10 +579,13 @@ static int lp_release(struct inode *inode, struct file *file) >>> { >>> unsigned int minor = iminor(inode); >>> + if (mutex_lock_interruptible(&lp_table[minor].port_mutex)) >>> + return -EINTR; > > ->release() return value is never checked, simply because there is nothing > to do with it. It will *not* leave file opened - it will simply leak, > with no way to recover from that. > > If you need to report some errors on close, do that in ->flush(). > If you ever see ->release() returning a non-zero value, you are very > likely looking at deeply confused code. > > Don't do that. ->release() can't fail, period. It should've been > void (*release)(struct file *), but for historical reasons it returns > int and there are too many instances to change that. Thank you for your patient explanation. Would it be acceptable to switch to mutex_lock() here? Looking at the code and historical changes, I don't see a compelling reason for the interruptible function here. -- Thanks, Nan