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 F2F54C433FE for ; Wed, 9 Nov 2022 03:14:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230172AbiKIDO6 (ORCPT ); Tue, 8 Nov 2022 22:14:58 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34580 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229496AbiKIDOy (ORCPT ); Tue, 8 Nov 2022 22:14:54 -0500 Received: from out0.migadu.com (out0.migadu.com [IPv6:2001:41d0:2:267::]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CB3FF22B3B for ; Tue, 8 Nov 2022 19:14:53 -0800 (PST) Content-Type: text/plain; charset=utf-8 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1667963691; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=DNSrYyuXAb9KkJUh6mgu5D2kNc+zrdhtGOh9S2mb3dc=; b=h1Osu+8NiKcZcp0eGLs+ttEcyg0B9JyICcvybRpwWwsNJhGYbmyXr4ca+Jbm6z8SSuowjs VvRRPPhrFbr1Mou9kTl4zyNQ1GMuHkK8bx1Ax9qkUwN3G1U/lBbb9ik1Ro0DFAIzsU6coB qXgrYpVJGSCwEvlTjmlvrsiEcqA18QI= MIME-Version: 1.0 Subject: Re: [PATCH v1] arch/x86/mm/hugetlbpage.c: pud_huge() returns 0 when using 2-level paging X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Muchun Song In-Reply-To: <20221107021010.2449306-1-naoya.horiguchi@linux.dev> Date: Wed, 9 Nov 2022 11:14:33 +0800 Cc: Linux Memory Management List , =?utf-8?B?VmlsbGUgU3lyasOkbMOk?= , Andrew Morton , David Hildenbrand , Mike Kravetz , Miaohe Lin , Liu Shixin , Yang Shi , Oscar Salvador , Muchun Song , Naoya Horiguchi , linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Message-Id: <6C1AF1FE-40EC-4B0F-A899-5BAE4BB0EA4A@linux.dev> References: <20221107021010.2449306-1-naoya.horiguchi@linux.dev> To: Naoya Horiguchi X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > On Nov 7, 2022, at 10:10, Naoya Horiguchi = wrote: >=20 > From: Naoya Horiguchi >=20 > The following bug is reported to be triggered when starting X on = x86-32 > system with i915: >=20 > [ 225.777375] kernel BUG at mm/memory.c:2664! > [ 225.777391] invalid opcode: 0000 [#1] PREEMPT SMP > [ 225.777405] CPU: 0 PID: 2402 Comm: Xorg Not tainted 6.1.0-rc3-bdg+ = #86 > [ 225.777415] Hardware name: /8I865G775-G, BIOS F1 08/29/2006 > [ 225.777421] EIP: __apply_to_page_range+0x24d/0x31c > [ 225.777437] Code: ff ff 8b 55 e8 8b 45 cc e8 0a 11 ec ff 89 d8 83 = c4 28 5b 5e 5f 5d c3 81 7d e0 a0 ef 96 c1 74 ad 8b 45 d0 e8 2d 83 49 00 = eb a3 <0f> 0b 25 00 f0 ff ff 81 eb 00 00 00 40 01 c3 8b 45 ec 8b 00 e8 = 76 > [ 225.777446] EAX: 00000001 EBX: c53a3b58 ECX: b5c00000 EDX: = c258aa00 > [ 225.777454] ESI: b5c00000 EDI: b5900000 EBP: c4b0fdb4 ESP: = c4b0fd80 > [ 225.777462] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 EFLAGS: = 00010202 > [ 225.777470] CR0: 80050033 CR2: b5900000 CR3: 053a3000 CR4: = 000006d0 > [ 225.777479] Call Trace: > [ 225.777486] ? i915_memcpy_init_early+0x63/0x63 [i915] > [ 225.777684] apply_to_page_range+0x21/0x27 > [ 225.777694] ? i915_memcpy_init_early+0x63/0x63 [i915] > [ 225.777870] remap_io_mapping+0x49/0x75 [i915] > [ 225.778046] ? i915_memcpy_init_early+0x63/0x63 [i915] > [ 225.778220] ? mutex_unlock+0xb/0xd > [ 225.778231] ? i915_vma_pin_fence+0x6d/0xf7 [i915] > [ 225.778420] vm_fault_gtt+0x2a9/0x8f1 [i915] > [ 225.778644] ? lock_is_held_type+0x56/0xe7 > [ 225.778655] ? lock_is_held_type+0x7a/0xe7 > [ 225.778663] ? 0xc1000000 > [ 225.778670] __do_fault+0x21/0x6a > [ 225.778679] handle_mm_fault+0x708/0xb21 > [ 225.778686] ? mt_find+0x21e/0x5ae > [ 225.778696] exc_page_fault+0x185/0x705 > [ 225.778704] ? doublefault_shim+0x127/0x127 > [ 225.778715] handle_exception+0x130/0x130 > [ 225.778723] EIP: 0xb700468a >=20 > Recently pud_huge() got aware of non-present entry by commit = 3a194f3f8ad0 > ("mm/hugetlb: make pud_huge() and follow_huge_pud() aware of = non-present > pud entry") to handle some special states of gigantic page. However, = it's > overlooked that pud_none() always returns false when running with = 2-level > paging, and as a result pmd_huge() can return true pointlessly. >=20 > Introduce "#if CONFIG_PGTABLE_LEVELS > 2" to pud_huge() to deal with = this. >=20 > Fixes: 3a194f3f8ad0 ("mm/hugetlb: make pud_huge() and = follow_huge_pud() aware of non-present pud entry") > Reported-by: Ville Syrj=C3=A4l=C3=A4 > Signed-off-by: Naoya Horiguchi > Cc: Reviewed-by: Muchun Song Thanks.