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 8FFFAC43334 for ; Thu, 2 Jun 2022 15:20:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232736AbiFBPUR (ORCPT ); Thu, 2 Jun 2022 11:20:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51678 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229899AbiFBPUQ (ORCPT ); Thu, 2 Jun 2022 11:20:16 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9763A2A5515; Thu, 2 Jun 2022 08:20:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; 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=bpvd1J1b0WtEe4XAB45cptIRNT3LAskrJazfccK+Ke0=; b=vmwGEc0Cc/yLViaTzRaFL5ig2s pQgxUIPOIQBksyLkqEXjgfJ01HzvYvW0Mp10p8q6vlhk0x5gzYpGjjt9Qb8Q3hUpShcMQNg6KfmeF J8OqwD+zl1nwFlwMGRGIj3g+FWscEHhCghzlY2GlfZrf/xMLBdXVFCb0K7dPaouyygVlfUUARQRWB fz8LZek8EAmKnWdtNpUP0gS+rHouxPs7SgWZplAiuweJ/FEtq3hunEhqy5KIU7zY4I8gFHOBDrBnT Nd9/1XDeScERELqRi6Cnds+lm0EUctZdvV3WMEvsNE9HMQtT9vEx3K7ndqvyqT7rlVmZSzXcrh8eQ VXXSw93A==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nwmcK-003gM1-Mi; Thu, 02 Jun 2022 15:20:08 +0000 Date: Thu, 2 Jun 2022 08:20:08 -0700 From: Christoph Hellwig To: "Fabio M. De Francesco" Cc: Chris Mason , Josef Bacik , David Sterba , Ira Weiny , linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/3] btrfs: Replace kmap() with kmap_local_page() Message-ID: References: <20220531145335.13954-1-fmdefrancesco@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220531145335.13954-1-fmdefrancesco@gmail.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org Turns out that while this looks good, it actually crashes when running xfstests. I think this is due to the fact that kmap sets the page address, which kmap_local_page does not. btrfs/150 1s ... [ 168.252943] run fstests btrfs/150 at 2022-06-02 15:17:11 [ 169.462292] BTRFS info (device vdb): flagging fs with big metadata feature [ 169.463728] BTRFS info (device vdb): disk space caching is enabled [ 169.464953] BTRFS info (device vdb): has skinny extents [ 170.596218] BTRFS: device fsid 37c6bae1-d3e5-47f8-87d5-87cd7240a1b4 devid 1 transid 5 /dev) [ 170.599471] BTRFS: device fsid 37c6bae1-d3e5-47f8-87d5-87cd7240a1b4 devid 2 transid 5 /dev) [ 170.657170] BTRFS info (device vdc): flagging fs with big metadata feature [ 170.659509] BTRFS info (device vdc): use zlib compression, level 3 [ 170.661190] BTRFS info (device vdc): disk space caching is enabled [ 170.670706] BTRFS info (device vdc): has skinny extents [ 170.714181] BTRFS info (device vdc): checking UUID tree [ 170.735058] BUG: kernel NULL pointer dereference, address: 0000000000000008 [ 170.736478] #PF: supervisor read access in kernel mode [ 170.737457] #PF: error_code(0x0000) - not-present page [ 170.738529] PGD 0 P4D 0 [ 170.739211] Oops: 0000 [#1] PREEMPT SMP PTI [ 170.740101] CPU: 0 PID: 43 Comm: kworker/u4:3 Not tainted 5.18.0-rc7+ #1539 [ 170.741478] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 [ 170.743246] Workqueue: btrfs-delalloc btrfs_work_helper [ 170.744282] RIP: 0010:zlib_compress_pages+0x128/0x670 [ 170.745346] Code: 00 00 00 16 00 00 48 01 e8 31 ed 48 c1 f8 06 48 c1 e0 0c 48 01 f8 49 89 0 [ 170.749042] RSP: 0018:ffffc9000038bc70 EFLAGS: 00010286 [ 170.750037] RAX: 0000000000000001 RBX: ffffc9000038bdb8 RCX: 0000000000000001 [ 170.751351] RDX: 0000000000002000 RSI: ffffffff82f532fb RDI: ffff888000000000 [ 170.752695] RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001 [ 170.754106] R10: 0000000000000000 R11: ffff8881039a5b30 R12: ffff888107befb48 [ 170.755449] R13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000000 [ 170.756922] FS: 0000000000000000(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000 [ 170.758642] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 170.759714] CR2: 0000000000000008 CR3: 000000010ab60000 CR4: 00000000000006f0 [ 170.761082] Call Trace: [ 170.761553] [ 170.761968] ? _raw_spin_unlock+0x24/0x40 [ 170.762776] btrfs_compress_pages+0xda/0x120 [ 170.763682] compress_file_range+0x3b9/0x840 [ 170.764570] async_cow_start+0xd/0x30 [ 170.765308] ? submit_compressed_extents+0x3c0/0x3c0 [ 170.766241] btrfs_work_helper+0xf5/0x3f0 [ 170.767009] ? lock_is_held_type+0xe2/0x140 [ 170.767817] process_one_work+0x239/0x550 [ 170.768633] ? process_one_work+0x550/0x550 [ 170.769447] worker_thread+0x4d/0x3a0 [ 170.770210] ? process_one_work+0x550/0x550 [ 170.771019] kthread+0xe2/0x110 [ 170.771623] ? kthread_complete_and_exit+0x20/0x20 [ 170.772697] ret_from_fork+0x22/0x30 [ 170.773454]