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 BD971C433F5 for ; Tue, 31 May 2022 22:30:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348417AbiEaWaE (ORCPT ); Tue, 31 May 2022 18:30:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36496 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244800AbiEaW3z (ORCPT ); Tue, 31 May 2022 18:29:55 -0400 Received: from mail-oi1-x22c.google.com (mail-oi1-x22c.google.com [IPv6:2607:f8b0:4864:20::22c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 02F2C9D4F1 for ; Tue, 31 May 2022 15:29:55 -0700 (PDT) Received: by mail-oi1-x22c.google.com with SMTP id s188so319676oie.4 for ; Tue, 31 May 2022 15:29:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=Pbw+0jsKWhRJki7yieC0UBF0GyCIgfnjgJoaKW5BNB8=; b=jPZNNPJCCS1Mp8YIDlUrMaG7kRuMY3eFi28K1eoc2Rk2Y8VjGLCypDCYsf8I7ndblT im+c+e83B610XfZ5QztkzD3/C/D/fAWJjnT+ePBZFaz16N/3AUP+EAxW0g4X4e2obbqg PX1OYw2HLADr7Gr5YwippHswKmp/6QzrCTTxLm3uAsMZ4CuxOS2vjqU6nsRdCpC3wjCD I/6e/XjxU1hYW+AYpFWDBdoTRhDIbWGybJGJuKz59NeO71/tBloQ9GM9YrdfaAOmiNOG yFAMq13PziPvpcuOWuw3nw+Lor9aGb5jwjkiT58umtDQAev3gB61FdMy3smwANqomPME 3epA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :mime-version:content-transfer-encoding; bh=Pbw+0jsKWhRJki7yieC0UBF0GyCIgfnjgJoaKW5BNB8=; b=gGgfyZlxuIJ4PLDYU+NU/npGz5uX/fq/fOtEy1WqhBhipksmYJNl7PpIkObHgrYqUC B4/rU1jE53i2PAkYcKAzq0ISluFFAWPdaBfpMQh8fqTmElUKFTQUH6te5EL3q/2Ak7g+ p8e/Vstwv6OfUz0j1a1SgteKAFquz3MnD46+/dyx6Ir96411S6w2VNk0xhDXVDHNZlby bSCWkSLIccubXQHQOOHuHx+bicMG7UMOjBGAyrYvUWtxuBD5jvD5fCLoYo+LSBR/yKmF wL/nbyKuNpAKx/KEteAFJRJSuA84vB4IeOLHapbksHmzOHoHXRReoGaNsEaR0335A943 +iFQ== X-Gm-Message-State: AOAM530x9HTtxdBh6tiK+xARWis9lQUEQE5KlHGZ9CruC4jVittYd6hy ZY10lnyOtRwZkPQ0tshYDNKie5wWj00= X-Google-Smtp-Source: ABdhPJwsSqoPfBxudtRP+82vlvVUbSr+vavGOO2krfCdLJtITblyPUlCAJSc3gcg1crKcMyARqm8SQ== X-Received: by 2002:a05:6808:1187:b0:322:2756:e23b with SMTP id j7-20020a056808118700b003222756e23bmr13683957oil.211.1654036194360; Tue, 31 May 2022 15:29:54 -0700 (PDT) Received: from server.roeck-us.net ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id c11-20020a4aaccb000000b0035eb4e5a6bbsm76185oon.17.2022.05.31.15.29.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 31 May 2022 15:29:53 -0700 (PDT) Sender: Guenter Roeck From: Guenter Roeck To: Andrew Morton Cc: Steven Rostedt , linux-kernel@vger.kernel.org, Guenter Roeck Subject: [PATCH] lib/list_debug.c: Detect uninitialized lists Date: Tue, 31 May 2022 15:29:51 -0700 Message-Id: <20220531222951.92073-1-linux@roeck-us.net> X-Mailer: git-send-email 2.35.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In some circumstances, attempts are made to add entries to or to remove entries from an uninitialized list. A prime example is amdgpu_bo_vm_destroy(): It is indirectly called from ttm_bo_init_reserved() if that function fails, and tries to remove an entry from a list. However, that list is only initialized in amdgpu_bo_create_vm() after the call to ttm_bo_init_reserved() returned success. This results in crashes such as BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 1 PID: 1479 Comm: chrome Not tainted 5.10.110-15768-g29a72e65dae5 Hardware name: Google Grunt/Grunt, BIOS Google_Grunt.11031.149.0 07/15/2020 RIP: 0010:__list_del_entry_valid+0x26/0x7d ... Call Trace: amdgpu_bo_vm_destroy+0x48/0x8b ttm_bo_init_reserved+0x1d7/0x1e0 amdgpu_bo_create+0x212/0x476 ? amdgpu_bo_user_destroy+0x23/0x23 ? kmem_cache_alloc+0x60/0x271 amdgpu_bo_create_vm+0x40/0x7d amdgpu_vm_pt_create+0xe8/0x24b ... Check if the list's prev and next pointers are NULL to catch such problems. Signed-off-by: Guenter Roeck --- lib/list_debug.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/lib/list_debug.c b/lib/list_debug.c index 9daa3fb9d1cd..d98d43f80958 100644 --- a/lib/list_debug.c +++ b/lib/list_debug.c @@ -20,7 +20,11 @@ bool __list_add_valid(struct list_head *new, struct list_head *prev, struct list_head *next) { - if (CHECK_DATA_CORRUPTION(next->prev != prev, + if (CHECK_DATA_CORRUPTION(prev == NULL, + "list_add corruption. prev is NULL.\n") || + CHECK_DATA_CORRUPTION(next == NULL, + "list_add corruption. next is NULL.\n") || + CHECK_DATA_CORRUPTION(next->prev != prev, "list_add corruption. next->prev should be prev (%px), but was %px. (next=%px).\n", prev, next->prev, next) || CHECK_DATA_CORRUPTION(prev->next != next, @@ -42,7 +46,11 @@ bool __list_del_entry_valid(struct list_head *entry) prev = entry->prev; next = entry->next; - if (CHECK_DATA_CORRUPTION(next == LIST_POISON1, + if (CHECK_DATA_CORRUPTION(next == NULL, + "list_del corruption, %px->next is NULL\n", entry) || + CHECK_DATA_CORRUPTION(prev == NULL, + "list_del corruption, %px->prev is NULL\n", entry) || + CHECK_DATA_CORRUPTION(next == LIST_POISON1, "list_del corruption, %px->next is LIST_POISON1 (%px)\n", entry, LIST_POISON1) || CHECK_DATA_CORRUPTION(prev == LIST_POISON2, -- 2.35.1