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 9BB95C7EE24 for ; Sat, 29 Apr 2023 01:20:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347237AbjD2BUn (ORCPT ); Fri, 28 Apr 2023 21:20:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36972 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347049AbjD2BUm (ORCPT ); Fri, 28 Apr 2023 21:20:42 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5754F3584; Fri, 28 Apr 2023 18:20:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=BaIEj2paZYE/uU2XkcW2I8y0R+043vPSdJ9uniAsh0U=; b=Fu1HC8bUG02gPzRUECQ6ysoDOs TKxxmHyyETr+yycfGwhDUSeMV9sMGtard9Y9x6iKaNQrEjTizdLrKfJqajF9FFqYC0FcARAJBzYa7 QmDsQyBNdOb1YuUCNd0jOstr5EUUo+rkNCx68RH6ucdm2kUyF+oMxXeeKPlKwzVpW0Vs2hPKvplhl zBtm35j8R0bVRMTrCVHq8C/RgnPDcuECqaH7jXz7zqz1yCjsGcZrjUCYWzP4bIZvk1TGoHdLj7G7Z Cb6pFJcswSczJFWlK1VT+VeMjZesZ6hXXpaiKMKi4EFId/Pr54k+/0BaupArt2vjbPiYkfYlfTNsz jgLrdWuA==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1psZG6-0059h2-19; Sat, 29 Apr 2023 01:20:18 +0000 Date: Sat, 29 Apr 2023 02:20:17 +0100 From: Matthew Wilcox To: Luis Chamberlain Cc: Christoph Hellwig , Pankaj Raghav , Daniel Gomez , Jens Axboe , Miklos Szeredi , "Darrick J. Wong" , Andrew Morton , David Howells , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, ceph-devel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com, linux-xfs@vger.kernel.org, linux-nfs@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 17/17] fs: add CONFIG_BUFFER_HEAD Message-ID: References: <20230424054926.26927-1-hch@lst.de> <20230424054926.26927-18-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Fri, Apr 28, 2023 at 05:11:57PM -0700, Luis Chamberlain wrote: > [ 11.245248] BUG: kernel NULL pointer dereference, address: 0000000000000000 > [ 11.254581] #PF: supervisor read access in kernel mode > [ 11.257387] #PF: error_code(0x0000) - not-present page > [ 11.260921] PGD 0 P4D 0 > [ 11.262600] Oops: 0000 [#1] PREEMPT SMP PTI > [ 11.264993] CPU: 7 PID: 198 Comm: (udev-worker) Not tainted 6.3.0-large-block-20230426 #2 > [ 11.269385] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.0-debian-1.16.0-5 04/01/2014 > [ 11.275054] RIP: 0010:iomap_page_create.isra.0+0xc/0xd0 > [ 11.277924] Code: 41 5e 41 5f c3 cc cc cc cc 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 41 54 55 48 89 f5 53 <48> 8b 06 48 c1 e8 0d 89 c6 83 e6 01 0f 84 a1 00 00 00 4c 8b 65 28 > [ 11.287293] RSP: 0018:ffffb0f0805ef9d8 EFLAGS: 00010293 > [ 11.289964] RAX: ffff9de3c1fa8388 RBX: ffffb0f0805efa78 RCX: 000000037ffe0000 > [ 11.293212] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000000000000000d > [ 11.296485] RBP: 0000000000000000 R08: 0000000000021000 R09: ffffffff9c733b20 > [ 11.299724] R10: 0000000000000001 R11: 000000000000c000 R12: 0000000000000000 > [ 11.302974] R13: ffffffff9be96260 R14: ffffb0f0805efa58 R15: 0000000000000000 RSI is argument 2, which is folio. Code starting with the faulting instruction =========================================== 0: 48 8b 06 mov (%rsi),%rax 3: 48 c1 e8 0d shr $0xd,%rax Looks to me like a NULL folio was passed into iomap_page_create(). > [ 11.306206] FS: 00007f03ea8368c0(0000) GS:ffff9de43bdc0000(0000) knlGS:0000000000000000 > [ 11.309949] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 11.312464] CR2: 0000000000000000 CR3: 0000000117ec6006 CR4: 0000000000770ee0 > [ 11.315442] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > [ 11.318310] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > [ 11.321010] PKRU: 55555554 > [ 11.322212] Call Trace: > [ 11.323224] > [ 11.324146] iomap_readpage_iter+0x96/0x300 > [ 11.325694] iomap_readahead+0x174/0x2d0 > [ 11.327129] read_pages+0x69/0x1f0 > [ 11.329751] page_cache_ra_unbounded+0x187/0x1d0 ... that shouldn't be possible. read_pages() allocates pages, puts them in the page cache and tells the filesystem to fill them in. In your patches, did you call mapping_set_large_folios() anywhere?