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=-19.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 60F51C433E2 for ; Mon, 29 Mar 2021 08:50:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4CCF76192E for ; Mon, 29 Mar 2021 08:50:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235557AbhC2It4 (ORCPT ); Mon, 29 Mar 2021 04:49:56 -0400 Received: from mail.kernel.org ([198.145.29.99]:53528 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234590AbhC2IdV (ORCPT ); Mon, 29 Mar 2021 04:33:21 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3281A619B9; Mon, 29 Mar 2021 08:32:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1617006729; bh=q4V0SiQrF84Nq9VKx+LEJXOgjK2tKh2XmOktLkFt6cY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=u85GARUhySxRlnyrLJOR419rDmMpnr2Aw+Dk7tgjDvRhgYz7JSMG5U7sLR+6yDaVX Aq3MHzRU8YqmIakh6xCpDsb66iO8VH0eqeEUfLdzV81FHCzuvYeZzMpbQiiqsCGWVU b/dTi4dHdfxKeZZALA2ukwVbxQMrsBouL81BdCZk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Neal Gompa , Josef Bacik , David Sterba Subject: [PATCH 5.11 070/254] btrfs: initialize device::fs_info always Date: Mon, 29 Mar 2021 09:56:26 +0200 Message-Id: <20210329075635.456453790@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210329075633.135869143@linuxfoundation.org> References: <20210329075633.135869143@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Josef Bacik commit 820a49dafc3304de06f296c35c9ff1ebc1666343 upstream. Neal reported a panic trying to use -o rescue=all BUG: kernel NULL pointer dereference, address: 0000000000000030 PGD 0 P4D 0 Oops: 0000 [#1] SMP NOPTI CPU: 0 PID: 696 Comm: mount Tainted: G W 5.12.0-rc2+ #296 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014 RIP: 0010:btrfs_device_init_dev_stats+0x1d/0x200 RSP: 0018:ffffafaec1483bb8 EFLAGS: 00010286 RAX: 0000000000000000 RBX: ffff9a5715bcb298 RCX: 0000000000000070 RDX: ffff9a5703248000 RSI: ffff9a57052ea150 RDI: ffff9a5715bca400 RBP: ffff9a57052ea150 R08: 0000000000000070 R09: ffff9a57052ea150 R10: 000130faf0741c10 R11: 0000000000000000 R12: ffff9a5703700000 R13: 0000000000000000 R14: ffff9a5715bcb278 R15: ffff9a57052ea150 FS: 00007f600d122c40(0000) GS:ffff9a577bc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000030 CR3: 0000000112a46005 CR4: 0000000000370ef0 Call Trace: ? btrfs_init_dev_stats+0x1f/0xf0 ? kmem_cache_alloc+0xef/0x1f0 btrfs_init_dev_stats+0x5f/0xf0 open_ctree+0x10cb/0x1720 btrfs_mount_root.cold+0x12/0xea legacy_get_tree+0x27/0x40 vfs_get_tree+0x25/0xb0 vfs_kern_mount.part.0+0x71/0xb0 btrfs_mount+0x10d/0x380 legacy_get_tree+0x27/0x40 vfs_get_tree+0x25/0xb0 path_mount+0x433/0xa00 __x64_sys_mount+0xe3/0x120 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xae This happens because when we call btrfs_init_dev_stats we do device->fs_info->dev_root. However device->fs_info isn't initialized because we were only calling btrfs_init_devices_late() if we properly read the device root. However we don't actually need the device root to init the devices, this function simply assigns the devices their ->fs_info pointer properly, so this needs to be done unconditionally always so that we can properly dereference device->fs_info in rescue cases. Reported-by: Neal Gompa CC: stable@vger.kernel.org # 5.11+ Signed-off-by: Josef Bacik Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/disk-io.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -2300,8 +2300,9 @@ static int btrfs_read_roots(struct btrfs } else { set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state); fs_info->dev_root = root; - btrfs_init_devices_late(fs_info); } + /* Initialize fs_info for all devices in any case */ + btrfs_init_devices_late(fs_info); /* If IGNOREDATACSUMS is set don't bother reading the csum root. */ if (!btrfs_test_opt(fs_info, IGNOREDATACSUMS)) {