From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754030AbdJIIdK (ORCPT ); Mon, 9 Oct 2017 04:33:10 -0400 Received: from m12-18.163.com ([220.181.12.18]:44135 "EHLO m12-18.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753981AbdJIIdJ (ORCPT ); Mon, 9 Oct 2017 04:33:09 -0400 Subject: Re: [PATCH] pci: Fix a possible sleep-in-atomic bug in pci_set_power_state To: Greg KH Cc: patrik.r.jakobsson@gmail.com, airlied@linux.ie, bhelgaas@google.com, forest@alittletooquiet.net, simon@nikanor.nu, scott@matheina.com, tvboxspy@gmail.com, dan.a.cashman@gmail.com, golubev.mikhail@gmail.com, devel@driverdev.osuosl.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org References: <1507536980-9345-1-git-send-email-baijiaju1990@163.com> <20171009081747.GA23371@kroah.com> From: Jia-Ju Bai Message-ID: <511f30f4-1b9e-1b1a-aad8-6c0505b40e4e@163.com> Date: Mon, 9 Oct 2017 16:32:33 +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: <20171009081747.GA23371@kroah.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-CM-TRANSID: EsCowAAXoDIkNNtZFmiIMw--.9406S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7Ww4fKr45Ar47WFyfWFyfZwb_yoW8GrW8pF W7Wan5AFyrJ342vF42vF40vFyrKwnxZ3y7try09wnxWw17ZF9xKr4DtrWYyr98XrZ7XFnI yr12yryDWFsxCwUanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07b1dgXUUUUU= X-Originating-IP: [166.111.70.12] X-CM-SenderInfo: xedlyx5dmximizq6il2tof0z/1tbiYwRselaDvJ8NdAAAs+ Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Oh, sorry, I will send the patches for each driver. Thanks, Jia-Ju Bai On 2017/10/9 16:17, Greg KH wrote: > On Mon, Oct 09, 2017 at 04:16:20PM +0800, Jia-Ju Bai wrote: >> The drivers vt6655 and gma500 call pci_set_power_state under a spinlock, which may sleep. >> The function call paths are: >> gma_power_begin (acquire the spinlock) (drivers/gpu/drm/gma500/power.c) >> gma_resume_pci >> pci_set_power_state >> __pci_start_power_transition (drivers/pci/pci.c) >> msleep --> may sleep >> >> gma_power_begin (acquire the spinlock) (drivers/gpu/drm/gma500/power.c) >> gma_resume_pci >> pci_enable_device >> pci_enable_device_flags (drivers/pci/pci.c) >> do_pci_enable_device >> pci_set_power_state >> __pci_start_power_transition >> msleep --> may sleep >> >> vt6655_suspend (acquire the spinlock) (drivers/staging/vt6655/device_main.c) >> pci_set_power_state >> __pci_start_power_transition (drivers/pci/pci.c) >> msleep --> may sleep >> >> To fix these bugs, msleep is replaced with mdelay in __pci_start_power_transition >> >> These bugs are found by my static analysis tool and my code review. > Wait, no, why not fix the callers to not have a spinlock. Those are the > only users of these calls that are doing so incorrectly, don't change > the PCI core for the fault of 2 broken drivers. > > thanks, > > greg k-h