From nobody Tue Apr 7 07:07:55 2026 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 A6BA7ECAAA1 for ; Tue, 30 Aug 2022 06:59:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230268AbiH3G7T (ORCPT ); Tue, 30 Aug 2022 02:59:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49316 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229636AbiH3G7Q (ORCPT ); Tue, 30 Aug 2022 02:59:16 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 599BF564F6 for ; Mon, 29 Aug 2022 23:59:15 -0700 (PDT) Received: from dggpemm500022.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4MGyjQ5GlQzYd1M; Tue, 30 Aug 2022 14:54:50 +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 14:59:13 +0800 Received: from thunder-town.china.huawei.com (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 14:59:13 +0800 From: Zhen Lei To: Russell King , , , CC: Zhen Lei , Saravana Kannan , Kefeng Wang , "Linus Walleij" Subject: [PATCH v2] ARM: Add sanity check for dev->periphid in amba_probe() Date: Tue, 30 Aug 2022 14:54:13 +0800 Message-ID: <20220830065413.638-1-thunder.leizhen@huawei.com> X-Mailer: git-send-email 2.26.0.windows.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [10.174.178.55] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) 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 Content-Type: text/plain; charset="utf-8" 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=3D00000000 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; } =20 -static int amba_match(struct device *dev, struct device_driver *drv) +static int amba_prepare_periphid(struct device *dev) { struct amba_device *pcdev =3D to_amba_device(dev); - struct amba_driver *pcdrv =3D to_amba_driver(drv); =20 mutex_lock(&pcdev->periphid_lock); if (!pcdev->periphid) { @@ -228,6 +227,19 @@ static int amba_match(struct device *dev, struct devic= e_driver *drv) } mutex_unlock(&pcdev->periphid_lock); =20 + return 0; +} + +static int amba_match(struct device *dev, struct device_driver *drv) +{ + struct amba_device *pcdev =3D to_amba_device(dev); + struct amba_driver *pcdrv =3D to_amba_driver(drv); + int ret; + + ret =3D 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 =3D to_amba_device(dev); struct amba_driver *pcdrv =3D to_amba_driver(dev->driver); - const struct amba_id *id =3D amba_lookup(pcdrv->id_table, pcdev); + const struct amba_id *id; int ret; =20 + ret =3D amba_prepare_periphid(dev); + if (ret) + return ret; + + id =3D amba_lookup(pcdrv->id_table, pcdev); + do { ret =3D of_amba_device_decode_irq(pcdev); if (ret) --=20 2.25.1