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=-11.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 9483DC7114D for ; Sat, 15 Feb 2020 13:35:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 78119217F4 for ; Sat, 15 Feb 2020 13:35:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726129AbgBONfG (ORCPT ); Sat, 15 Feb 2020 08:35:06 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:57224 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725971AbgBONfG (ORCPT ); Sat, 15 Feb 2020 08:35:06 -0500 Received: from [5.158.153.53] (helo=tip-bot2.lab.linutronix.de) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1j2xb2-00084w-MP; Sat, 15 Feb 2020 14:35:00 +0100 Received: from [127.0.1.1] (localhost [IPv6:::1]) by tip-bot2.lab.linutronix.de (Postfix) with ESMTP id 091391C205F; Sat, 15 Feb 2020 14:35:00 +0100 (CET) Date: Sat, 15 Feb 2020 13:34:59 -0000 From: "tip-bot2 for Thomas Gleixner" Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: ras/urgent] x86/mce/amd: Fix kobject lifetime Cc: Thomas Gleixner , Borislav Petkov , , x86 , LKML In-Reply-To: <20200214082801.13836-1-bp@alien8.de> References: <20200214082801.13836-1-bp@alien8.de> MIME-Version: 1.0 Message-ID: <158177369962.13786.16098407006257585201.tip-bot2@tip-bot2> X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The following commit has been merged into the ras/urgent branch of tip: Commit-ID: 51dede9c05df2b78acd6dcf6a17d21f0877d2d7b Gitweb: https://git.kernel.org/tip/51dede9c05df2b78acd6dcf6a17d21f0877d2d7b Author: Thomas Gleixner AuthorDate: Thu, 13 Feb 2020 19:01:34 +01:00 Committer: Borislav Petkov CommitterDate: Fri, 14 Feb 2020 09:28:31 +01:00 x86/mce/amd: Fix kobject lifetime Accessing the MCA thresholding controls in sysfs concurrently with CPU hotplug can lead to a couple of KASAN-reported issues: BUG: KASAN: use-after-free in sysfs_file_ops+0x155/0x180 Read of size 8 at addr ffff888367578940 by task grep/4019 and BUG: KASAN: use-after-free in show_error_count+0x15c/0x180 Read of size 2 at addr ffff888368a05514 by task grep/4454 for example. Both result from the fact that the threshold block creation/teardown code frees the descriptor memory itself instead of defining proper ->release function and leaving it to the driver core to take care of that, after all sysfs accesses have completed. Do that and get rid of the custom freeing code, fixing the above UAFs in the process. [ bp: write commit message. ] Fixes: 95268664390b ("[PATCH] x86_64: mce_amd support for family 0x10 processors") Signed-off-by: Thomas Gleixner Signed-off-by: Borislav Petkov Cc: Link: https://lkml.kernel.org/r/20200214082801.13836-1-bp@alien8.de --- arch/x86/kernel/cpu/mce/amd.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/arch/x86/kernel/cpu/mce/amd.c b/arch/x86/kernel/cpu/mce/amd.c index e7313e5..52de616 100644 --- a/arch/x86/kernel/cpu/mce/amd.c +++ b/arch/x86/kernel/cpu/mce/amd.c @@ -1163,9 +1163,12 @@ static const struct sysfs_ops threshold_ops = { .store = store, }; +static void threshold_block_release(struct kobject *kobj); + static struct kobj_type threshold_ktype = { .sysfs_ops = &threshold_ops, .default_attrs = default_attrs, + .release = threshold_block_release, }; static const char *get_name(unsigned int bank, struct threshold_block *b) @@ -1367,8 +1370,12 @@ static int threshold_create_bank(unsigned int cpu, unsigned int bank) return err; } -static void deallocate_threshold_block(unsigned int cpu, - unsigned int bank) +static void threshold_block_release(struct kobject *kobj) +{ + kfree(to_block(kobj)); +} + +static void deallocate_threshold_block(unsigned int cpu, unsigned int bank) { struct threshold_block *pos = NULL; struct threshold_block *tmp = NULL; @@ -1378,13 +1385,11 @@ static void deallocate_threshold_block(unsigned int cpu, return; list_for_each_entry_safe(pos, tmp, &head->blocks->miscj, miscj) { - kobject_put(&pos->kobj); list_del(&pos->miscj); - kfree(pos); + kobject_put(&pos->kobj); } - kfree(per_cpu(threshold_banks, cpu)[bank]->blocks); - per_cpu(threshold_banks, cpu)[bank]->blocks = NULL; + kobject_put(&head->blocks->kobj); } static void __threshold_remove_blocks(struct threshold_bank *b)