From mboxrd@z Thu Jan 1 00:00:00 1970 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 C44C1ECAAD4 for ; Tue, 30 Aug 2022 10:12:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230237AbiH3KMf (ORCPT ); Tue, 30 Aug 2022 06:12:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34478 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230142AbiH3KLx (ORCPT ); Tue, 30 Aug 2022 06:11:53 -0400 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 871D6EA885 for ; Tue, 30 Aug 2022 03:07:35 -0700 (PDT) Received: from dggpemm500022.china.huawei.com (unknown [172.30.72.56]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4MH2xk49lDzHnVM; Tue, 30 Aug 2022 18:05:46 +0800 (CST) Received: from dggpemm500006.china.huawei.com (7.185.36.236) by dggpemm500022.china.huawei.com (7.185.36.162) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Tue, 30 Aug 2022 18:07:32 +0800 Received: from [10.174.178.55] (10.174.178.55) by dggpemm500006.china.huawei.com (7.185.36.236) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Tue, 30 Aug 2022 18:07:32 +0800 Subject: Re: [PATCH v2] ARM: Add sanity check for dev->periphid in amba_probe() To: "Russell King (Oracle)" CC: , , , Saravana Kannan , "Kefeng Wang" , Linus Walleij References: <20220830065413.638-1-thunder.leizhen@huawei.com> From: "Leizhen (ThunderTown)" Message-ID: <4236a152-c848-a8f9-45db-4b6b7b4b586a@huawei.com> Date: Tue, 30 Aug 2022 18:07:31 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.178.55] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To dggpemm500006.china.huawei.com (7.185.36.236) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/8/30 17:50, Russell King (Oracle) wrote: > Please don't send the patch system patches that have not had any chance > of review. The patch system is supposed to be for patches that are to > be applied. Okay, I get it now. > > Sending patches that are yet to be reviewed makes extra work for me. I'm so sorry. > > Thanks. > > On Tue, Aug 30, 2022 at 02:54:13PM +0800, Zhen Lei wrote: >> Commit f2d3b9a46e0e ("ARM: 9220/1: amba: Remove deferred device addition") >> forcibly invokes device_add() even if dev->periphid is not ready. Although >> it will be remedied in amba_match(): dev->periphid will be initialized >> if everything is in place; Otherwise, return -EPROBE_DEFER to block >> __driver_attach() from further execution. But not all drivers have .match >> hook, such as pl031, the dev->bus->probe will be called directly in >> __driver_attach(). Unfortunately, if dev->periphid is still not >> initialized, the following exception will be triggered. >> >> 8<--- cut here --- >> Unable to handle kernel NULL pointer dereference at virtual address 00000008 >> [00000008] *pgd=00000000 >> Internal error: Oops: 5 [#1] SMP ARM >> Modules linked in: >> CPU: 1 PID: 1 Comm: swapper/0 Not tainted 6.0.0-rc2+ #7 >> Hardware name: ARM-Versatile Express >> PC is at pl031_probe+0x8/0x208 >> LR is at amba_probe+0xf0/0x160 >> pc : 80698df8 lr : 8050eb54 psr: 80000013 >> sp : c0825df8 ip : 00000000 fp : 811fda38 >> r10: 00000000 r9 : 80d72470 r8 : fffffdfb >> r7 : 811fd800 r6 : be7eb330 r5 : 00000000 r4 : 811fd900 >> r3 : 80698df0 r2 : 37000000 r1 : 00000000 r0 : 811fd800 >> Flags: Nzcv IRQs on FIQs on Mode SVC_32 ISA ARM Segment none >> Control: 10c5387d Table: 6000406a DAC: 00000051 >> ... ... >> pl031_probe from amba_probe+0xf0/0x160 >> amba_probe from really_probe+0x118/0x290 >> really_probe from __driver_probe_device+0x84/0xe4 >> __driver_probe_device from driver_probe_device+0x30/0xd0 >> driver_probe_device from __driver_attach+0x8c/0xfc >> __driver_attach from bus_for_each_dev+0x70/0xb0 >> bus_for_each_dev from bus_add_driver+0x168/0x1f4 >> bus_add_driver from driver_register+0x7c/0x118 >> driver_register from do_one_initcall+0x44/0x1ec >> do_one_initcall from kernel_init_freeable+0x238/0x288 >> kernel_init_freeable from kernel_init+0x18/0x12c >> kernel_init from ret_from_fork+0x14/0x2c >> ... ... >> ---[ end trace 0000000000000000 ]--- >> >> Therefore, take the same action as in amba_match(): return -EPROBE_DEFER >> if dev->periphid is not ready in amba_probe(). >> >> Fixes: f2d3b9a46e0e ("ARM: 9220/1: amba: Remove deferred device addition") >> Signed-off-by: Zhen Lei >> --- >> KernelVersion: v6.0-rc3 >> drivers/amba/bus.c | 24 +++++++++++++++++++++--- >> 1 file changed, 21 insertions(+), 3 deletions(-) >> >> v1 --> v2: >> 1. Update this patch based on: >> https://lore.kernel.org/lkml/20220818172852.3548-1-isaacmanjarres@google.com/ >> 2. Move the operations of sanity checking and reading dev->periphid, >> updating uevent into new function amba_prepare_periphid(). >> >> diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c >> index 110a535648d2e1f..8e4c7e190880206 100644 >> --- a/drivers/amba/bus.c >> +++ b/drivers/amba/bus.c >> @@ -204,10 +204,9 @@ static int amba_read_periphid(struct amba_device *dev) >> return ret; >> } >> >> -static int amba_match(struct device *dev, struct device_driver *drv) >> +static int amba_prepare_periphid(struct device *dev) >> { >> struct amba_device *pcdev = to_amba_device(dev); >> - struct amba_driver *pcdrv = to_amba_driver(drv); >> >> mutex_lock(&pcdev->periphid_lock); >> if (!pcdev->periphid) { >> @@ -228,6 +227,19 @@ static int amba_match(struct device *dev, struct device_driver *drv) >> } >> mutex_unlock(&pcdev->periphid_lock); >> >> + return 0; >> +} >> + >> +static int amba_match(struct device *dev, struct device_driver *drv) >> +{ >> + struct amba_device *pcdev = to_amba_device(dev); >> + struct amba_driver *pcdrv = to_amba_driver(drv); >> + int ret; >> + >> + ret = amba_prepare_periphid(dev); >> + if (ret) >> + return ret; >> + >> /* When driver_override is set, only bind to the matching driver */ >> if (pcdev->driver_override) >> return !strcmp(pcdev->driver_override, drv->name); >> @@ -278,9 +290,15 @@ static int amba_probe(struct device *dev) >> { >> struct amba_device *pcdev = to_amba_device(dev); >> struct amba_driver *pcdrv = to_amba_driver(dev->driver); >> - const struct amba_id *id = amba_lookup(pcdrv->id_table, pcdev); >> + const struct amba_id *id; >> int ret; >> >> + ret = amba_prepare_periphid(dev); >> + if (ret) >> + return ret; >> + >> + id = amba_lookup(pcdrv->id_table, pcdev); >> + >> do { >> ret = of_amba_device_decode_irq(pcdev); >> if (ret) >> -- >> 2.25.1 >> >> > -- Regards, Zhen Lei