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 X-Spam-Level: X-Spam-Status: No, score=-14.6 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7D34BC282CD for ; Mon, 28 Jan 2019 17:34:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 409232147A for ; Mon, 28 Jan 2019 17:34:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="W0dxgfhY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730507AbfA1ReE (ORCPT ); Mon, 28 Jan 2019 12:34:04 -0500 Received: from mail-lf1-f68.google.com ([209.85.167.68]:38065 "EHLO mail-lf1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730181AbfA1ReA (ORCPT ); Mon, 28 Jan 2019 12:34:00 -0500 Received: by mail-lf1-f68.google.com with SMTP id a8so12485082lfk.5 for ; Mon, 28 Jan 2019 09:33:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=mFDYS/TE9ERsAbfvybfOq/tSngwJltMjuujQp8mS1GM=; b=W0dxgfhYnlLFtHe+Y7NSynOAnat+UXpgtKlPISfrrIffUrUFqTzuxG0HBRxw+PHueX CnfQjnvd9S5HvvJPJUjMCyQgqimgcidRJH70s+zKn+TnNIZg4PlBZEZxzrTwNE9wPwVA uxUnWH36CvR9co4qrcXQ9vgsAXDPC4N42SLOBbQrAlspXu1vj/51Kg+14pvrgOtBoOoI cUrxn1TOWifk5/ynsvAR+CKWyTV3MG9ngHHkFJfZugbU5Fe8F4KnzOxxKkDm8KSfB4c9 X1d9NC4ujzmZa/3GRrA9UcIgw/Gdqu29eLSq7v5Yz/fIgv4M6cGOcyw7tjri2ruzxd/5 Xqzg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=mFDYS/TE9ERsAbfvybfOq/tSngwJltMjuujQp8mS1GM=; b=YZAxkpdZ4VZWgJK765XlOtjijqc8IrvexK+Qkb/uqbcm7k6IyCHwOCAiV19ZK0b3Eh SDNcCEILUmjxWgKlYsvZaq8FvcvesVkz5KvMhHUXUgQc27WvDVJPDIXW72t8QQdvLZky UozCd4d0xhTbOMnAhXPyqvwdUx6ldEJ0GzUNSR+nRmEDtFymcdN+dMgMzv3hYH6C0m8P UkrYoWIyRZo7C5KjKVL0kTVxajcFotHorkel5jEQlmZ0qRwaAQ9ebXwyx9qa8HwTK/xD i+BigA1nuiawIkzH6bQTKdQJWMko2FWkFktV7k624cFc0VE41mABt3B0p/cuU+fShMad 0TkQ== X-Gm-Message-State: AJcUukeGlUICYNTiu13zGjqlLsJLFMV8pbso8qP4GeRuW+hQzgJn5xbh b8se5AM8Uzt1j7ZCf0iuhF336nlhl4aRF9WITuMdvcSt9hU= X-Google-Smtp-Source: ALg8bN5RROg7qCOCY0G0QoPeg/pj9LPMDuyomeQhTko/oKZcTh4I9O7OjyDGktsX2hX3BGZhzTYSOIaGbNaSL18+kgA= X-Received: by 2002:a19:54d7:: with SMTP id b84mr17459499lfl.131.1548696837311; Mon, 28 Jan 2019 09:33:57 -0800 (PST) MIME-Version: 1.0 References: <20190126102320.14120-1-christian@brauner.io> In-Reply-To: <20190126102320.14120-1-christian@brauner.io> From: Todd Kjos Date: Mon, 28 Jan 2019 09:33:45 -0800 Message-ID: Subject: Re: [PATCH] binder: fix CONFIG_ANDROID_BINDER_DEVICES To: Christian Brauner Cc: Greg Kroah-Hartman , Todd Kjos , "open list:ANDROID DRIVERS" , LKML , linux-fsdevel@vger.kernel.org, =?UTF-8?B?QXJ2ZSBIasO4bm5ldsOlZw==?= , Martijn Coenen , joel@joelfernandes.org, Martijn Coenen Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jan 26, 2019 at 2:23 AM Christian Brauner wrote: > > Several users have tried to only rely on binderfs to provide binder devices > and set CONFIG_ANDROID_BINDER_DEVICES="" empty. This is a great use-case of > binderfs and one that was always intended to work. However, this is > currently not possible since setting CONFIG_ANDROID_BINDER_DEVICES="" emtpy > will simply panic the kernel: > > kobject: (00000000028c2f79): attempted to be registered with empty name! > WARNING: CPU: 7 PID: 1703 at lib/kobject.c:228 kobject_add_internal+0x288/0x2b0 > Modules linked in: binder_linux(+) bridge stp llc ipmi_ssif gpio_ich dcdbas coretemp kvm_intel kvm irqbypass serio_raw input_leds lpc_ich i5100_edac mac_hid ipmi_si ipmi_devintf ipmi_msghandler sch_fq_codel ib_i > CPU: 7 PID: 1703 Comm: modprobe Not tainted 5.0.0-rc2-brauner-binderfs #263 > Hardware name: Dell DCS XS24-SC2 /XS24-SC2 , BIOS S59_3C20 04/07/2011 > RIP: 0010:kobject_add_internal+0x288/0x2b0 > Code: 12 95 48 c7 c7 78 63 3b 95 e8 77 35 71 ff e9 91 fe ff ff 0f 0b eb a7 0f 0b eb 9a 48 89 de 48 c7 c7 00 63 3b 95 e8 f8 95 6a ff <0f> 0b 41 bc ea ff ff ff e9 6d fe ff ff 41 bc fe ff ff ff e9 62 fe > RSP: 0018:ffff973f84237a30 EFLAGS: 00010282 > RAX: 0000000000000000 RBX: ffff8b53e2472010 RCX: 0000000000000006 > RDX: 0000000000000007 RSI: 0000000000000086 RDI: ffff8b53edbd63a0 > RBP: ffff973f84237a60 R08: 0000000000000342 R09: 0000000000000004 > R10: ffff973f84237af0 R11: 0000000000000001 R12: 0000000000000000 > R13: ffff8b53e9f1a1e0 R14: 00000000e9f1a1e0 R15: 0000000000a00037 > FS: 00007fbac36f7540(0000) GS:ffff8b53edbc0000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007fbac364cfa7 CR3: 00000004a6d48000 CR4: 00000000000406e0 > Call Trace: > kobject_add+0x71/0xd0 > ? _cond_resched+0x19/0x40 > ? mutex_lock+0x12/0x40 > device_add+0x12e/0x6b0 > device_create_groups_vargs+0xe4/0xf0 > device_create_with_groups+0x3f/0x60 > ? _cond_resched+0x19/0x40 > misc_register+0x140/0x180 > binder_init+0x1ed/0x2d4 [binder_linux] > ? trace_event_define_fields_binder_transaction_fd_send+0x8e/0x8e [binder_linux] > do_one_initcall+0x4a/0x1c9 > ? _cond_resched+0x19/0x40 > ? kmem_cache_alloc_trace+0x151/0x1c0 > do_init_module+0x5f/0x216 > load_module+0x223d/0x2b20 > __do_sys_finit_module+0xfc/0x120 > ? __do_sys_finit_module+0xfc/0x120 > __x64_sys_finit_module+0x1a/0x20 > do_syscall_64+0x5a/0x120 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > RIP: 0033:0x7fbac3202839 > Code: 00 f3 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 1f f6 2c 00 f7 d8 64 89 01 48 > RSP: 002b:00007ffd1494a908 EFLAGS: 00000246 ORIG_RAX: 0000000000000139 > RAX: ffffffffffffffda RBX: 000055b629ebec60 RCX: 00007fbac3202839 > RDX: 0000000000000000 RSI: 000055b629c20d2e RDI: 0000000000000003 > RBP: 000055b629c20d2e R08: 0000000000000000 R09: 000055b629ec2310 > R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000000 > R13: 000055b629ebed70 R14: 0000000000040000 R15: 000055b629ebec60 > > So check for the empty string since strsep() will otherwise return the > emtpy string which will cause kobject_add_internal() to panic when trying > to add a kobject with an emtpy name. > > Fixes: ac4812c5ffbb ("binder: Support multiple /dev instances") > Cc: Martijn Coenen > Signed-off-by: Christian Brauner Acked-by: Todd Kjos > --- > drivers/android/binder.c | 30 ++++++++++++++++-------------- > 1 file changed, 16 insertions(+), 14 deletions(-) > > diff --git a/drivers/android/binder.c b/drivers/android/binder.c > index 751d76173f81..5f7d6fe06eec 100644 > --- a/drivers/android/binder.c > +++ b/drivers/android/binder.c > @@ -5898,21 +5898,23 @@ static int __init binder_init(void) > &transaction_log_fops); > } > > - /* > - * Copy the module_parameter string, because we don't want to > - * tokenize it in-place. > - */ > - device_names = kstrdup(binder_devices_param, GFP_KERNEL); > - if (!device_names) { > - ret = -ENOMEM; > - goto err_alloc_device_names_failed; > - } > + if (strcmp(binder_devices_param, "") != 0) { > + /* > + * Copy the module_parameter string, because we don't want to > + * tokenize it in-place. > + */ > + device_names = kstrdup(binder_devices_param, GFP_KERNEL); > + if (!device_names) { > + ret = -ENOMEM; > + goto err_alloc_device_names_failed; > + } > > - device_tmp = device_names; > - while ((device_name = strsep(&device_tmp, ","))) { > - ret = init_binder_device(device_name); > - if (ret) > - goto err_init_binder_device_failed; > + device_tmp = device_names; > + while ((device_name = strsep(&device_tmp, ","))) { > + ret = init_binder_device(device_name); > + if (ret) > + goto err_init_binder_device_failed; > + } > } > > ret = init_binderfs(); > -- > 2.20.1 >