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 9A1FFC433FE for ; Thu, 16 Dec 2021 15:41:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238596AbhLPPln (ORCPT ); Thu, 16 Dec 2021 10:41:43 -0500 Received: from smtp23.cstnet.cn ([159.226.251.23]:56034 "EHLO cstnet.cn" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S232607AbhLPPlm (ORCPT ); Thu, 16 Dec 2021 10:41:42 -0500 Received: from localhost.localdomain (unknown [124.16.138.126]) by APP-03 (Coremail) with SMTP id rQCowADHz1saXrthvu1IAw--.262S2; Thu, 16 Dec 2021 23:41:14 +0800 (CST) From: Jiasheng Jiang To: gregkh@linuxfoundation.org, jirislaby@kernel.org Cc: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, Jiasheng Jiang Subject: Re: Re: Re: [PATCH v3] serial: pch_uart: potential dereference of null pointer Date: Thu, 16 Dec 2021 23:41:13 +0800 Message-Id: <20211216154113.423442-1-jiasheng@iscas.ac.cn> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID: rQCowADHz1saXrthvu1IAw--.262S2 X-Coremail-Antispam: 1UD129KBjvdXoWrWry5CF4xXw18Xr4DAw4Utwb_yoWxXFg_WF 9IgrsrG395Wa97Ary3JFsrta43tFs3uryYqr45X34SqrZ5XFy5Jwn8tr95Jr4xGFsYyF4v yFWvvrW2vw15ZjkaLaAFLSUrUUUUUb8apTn2vfkv8UJUUUU8Yxn0WfASr-VFAUDa7-sFnT 9fnUUIcSsGvfJTRUUUbckFF20E14v26r1j6r4UM7CY07I20VC2zVCF04k26cxKx2IYs7xG 6rWj6s0DM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48ve4kI8w A2z4x0Y4vE2Ix0cI8IcVAFwI0_Ar0_tr1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI0_Cr0_ Gr1UM28EF7xvwVC2z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s 0DM2AIxVAIcxkEcVAq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xII jxv20xvE14v26r1j6r18McIj6I8E87Iv67AKxVW8JVWxJwAm72CE4IkC6x0Yz7v_Jr0_Gr 1lF7xvr2IYc2Ij64vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7MxkIecxEwVAFwVW5WwCF 04k20xvY0x0EwIxGrwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r 18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_JF0_Jw1lIxkGc2Ij64vI r41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Jr0_Gr 1lIxAIcVCF04k26cxKx2IYs7xG6rWUJVWrZr1UMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF 0xvEx4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x0JU8rc3UUUUU= X-Originating-IP: [124.16.138.126] X-CM-SenderInfo: pmld2xxhqjqxpvfd2hldfou0/ Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 16, 2021 at 11:24:36PM +0800, Greg KH wrote: > Did you run the kernel before your change and then after your change to > ensure that the failure you saw before your change is now properly > fixed? > > How did you test this? Thank you for your answer. But I haven't run it yet. And in fact I don't know how to trigger the alloc failure. I just find the other place like eni_init_one() in `drivers/atm/eni.c` check the return value of the dma_alloc_coherent(). So that's possible to alloc failure. Therefore, in order to avoid the dereference of the null pointer, it might be better to deal with it. Sincerely thanks, jiasheng jiang