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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 62B27C433DB for ; Sun, 24 Jan 2021 13:23:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 337A8227BF for ; Sun, 24 Jan 2021 13:23:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726111AbhAXNW7 (ORCPT ); Sun, 24 Jan 2021 08:22:59 -0500 Received: from wforward1-smtp.messagingengine.com ([64.147.123.30]:53377 "EHLO wforward1-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726050AbhAXNW7 (ORCPT ); Sun, 24 Jan 2021 08:22:59 -0500 Received: from compute4.internal (compute4.nyi.internal [10.202.2.44]) by mailforward.west.internal (Postfix) with ESMTP id 9636BB6B; Sun, 24 Jan 2021 08:21:52 -0500 (EST) Received: from mailfrontend2 ([10.202.2.163]) by compute4.internal (MEProxy); Sun, 24 Jan 2021 08:21:52 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:from:message-id:mime-version:subject:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm1; bh=X4DnOw WIDzpvVP6tYh9iApf8IjopiCE/nua/491dE04=; b=SpoZMNgZnP5ep9W5Tn0Idl x0wsy7t5nVR/Vlv5opOX8bu11xllX2kv0iqcsB2QujFvtARdcjB5IIF1og+miGTe 2MKW2Rc8nDHCHVTZnS6GsIbsI00pZvzKumugdilorQANpqM/JgRiZX3ULHi5asDS okr5Y5cVAt0stfn+L97VBgPjkXAmu+TOA6oBgKz7VB1uejfPnPDtMBNpSqcOz+tw N0y9k7rhdrjyBDJm/A+K/Tl6uejsEo5H1XL18vRtsTtVT9gfVlRwMMd6VJo5x19V GCtgoWrBGUaOZPlVRdSHM852C8HBKqqE3/K6VA/IabQuVOidjTVqBf0xjjP4tZuA == X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduledrvddugdehvdcutefuodetggdotefrodftvf curfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfghnecu uegrihhlohhuthemuceftddtnecunecujfgurhepuffvhfffkfggtgfgsehtkeertddttd flnecuhfhrohhmpeeoghhrvghgkhhhsehlihhnuhigfhhouhhnuggrthhiohhnrdhorhhg qeenucggtffrrghtthgvrhhnpeeiteevheeuvdfhtdfgvdeiieehheefleevveehjedute evueevledujeejgfetheenucfkphepkeefrdekiedrjeegrdeigeenucevlhhushhtvghr ufhiiigvpeehnecurfgrrhgrmhepmhgrihhlfhhrohhmpehgrhgvgheskhhrohgrhhdrtg homh X-ME-Proxy: Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) by mail.messagingengine.com (Postfix) with ESMTPA id D12811080057; Sun, 24 Jan 2021 08:21:51 -0500 (EST) Subject: FAILED: patch "[PATCH] btrfs: fix lockdep splat in btrfs_recover_relocation" failed to apply to 4.4-stable tree To: josef@toxicpanda.com, dsterba@suse.com, johannes.thumshirn@wdc.com, wqu@suse.com Cc: From: Date: Sun, 24 Jan 2021 14:21:50 +0100 Message-ID: <161149451017342@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From fb286100974e7239af243bc2255a52f29442f9c8 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Wed, 16 Dec 2020 11:22:14 -0500 Subject: [PATCH] btrfs: fix lockdep splat in btrfs_recover_relocation While testing the error paths of relocation I hit the following lockdep splat: ====================================================== WARNING: possible circular locking dependency detected 5.10.0-rc6+ #217 Not tainted ------------------------------------------------------ mount/779 is trying to acquire lock: ffffa0e676945418 (&fs_info->balance_mutex){+.+.}-{3:3}, at: btrfs_recover_balance+0x2f0/0x340 but task is already holding lock: ffffa0e60ee31da8 (btrfs-root-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x27/0x100 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (btrfs-root-00){++++}-{3:3}: down_read_nested+0x43/0x130 __btrfs_tree_read_lock+0x27/0x100 btrfs_read_lock_root_node+0x31/0x40 btrfs_search_slot+0x462/0x8f0 btrfs_update_root+0x55/0x2b0 btrfs_drop_snapshot+0x398/0x750 clean_dirty_subvols+0xdf/0x120 btrfs_recover_relocation+0x534/0x5a0 btrfs_start_pre_rw_mount+0xcb/0x170 open_ctree+0x151f/0x1726 btrfs_mount_root.cold+0x12/0xea legacy_get_tree+0x30/0x50 vfs_get_tree+0x28/0xc0 vfs_kern_mount.part.0+0x71/0xb0 btrfs_mount+0x10d/0x380 legacy_get_tree+0x30/0x50 vfs_get_tree+0x28/0xc0 path_mount+0x433/0xc10 __x64_sys_mount+0xe3/0x120 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #1 (sb_internal#2){.+.+}-{0:0}: start_transaction+0x444/0x700 insert_balance_item.isra.0+0x37/0x320 btrfs_balance+0x354/0xf40 btrfs_ioctl_balance+0x2cf/0x380 __x64_sys_ioctl+0x83/0xb0 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #0 (&fs_info->balance_mutex){+.+.}-{3:3}: __lock_acquire+0x1120/0x1e10 lock_acquire+0x116/0x370 __mutex_lock+0x7e/0x7b0 btrfs_recover_balance+0x2f0/0x340 open_ctree+0x1095/0x1726 btrfs_mount_root.cold+0x12/0xea legacy_get_tree+0x30/0x50 vfs_get_tree+0x28/0xc0 vfs_kern_mount.part.0+0x71/0xb0 btrfs_mount+0x10d/0x380 legacy_get_tree+0x30/0x50 vfs_get_tree+0x28/0xc0 path_mount+0x433/0xc10 __x64_sys_mount+0xe3/0x120 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: &fs_info->balance_mutex --> sb_internal#2 --> btrfs-root-00 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(btrfs-root-00); lock(sb_internal#2); lock(btrfs-root-00); lock(&fs_info->balance_mutex); *** DEADLOCK *** 2 locks held by mount/779: #0: ffffa0e60dc040e0 (&type->s_umount_key#47/1){+.+.}-{3:3}, at: alloc_super+0xb5/0x380 #1: ffffa0e60ee31da8 (btrfs-root-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x27/0x100 stack backtrace: CPU: 0 PID: 779 Comm: mount Not tainted 5.10.0-rc6+ #217 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014 Call Trace: dump_stack+0x8b/0xb0 check_noncircular+0xcf/0xf0 ? trace_call_bpf+0x139/0x260 __lock_acquire+0x1120/0x1e10 lock_acquire+0x116/0x370 ? btrfs_recover_balance+0x2f0/0x340 __mutex_lock+0x7e/0x7b0 ? btrfs_recover_balance+0x2f0/0x340 ? btrfs_recover_balance+0x2f0/0x340 ? rcu_read_lock_sched_held+0x3f/0x80 ? kmem_cache_alloc_trace+0x2c4/0x2f0 ? btrfs_get_64+0x5e/0x100 btrfs_recover_balance+0x2f0/0x340 open_ctree+0x1095/0x1726 btrfs_mount_root.cold+0x12/0xea ? rcu_read_lock_sched_held+0x3f/0x80 legacy_get_tree+0x30/0x50 vfs_get_tree+0x28/0xc0 vfs_kern_mount.part.0+0x71/0xb0 btrfs_mount+0x10d/0x380 ? __kmalloc_track_caller+0x2f2/0x320 legacy_get_tree+0x30/0x50 vfs_get_tree+0x28/0xc0 ? capable+0x3a/0x60 path_mount+0x433/0xc10 __x64_sys_mount+0xe3/0x120 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 This is straightforward to fix, simply release the path before we setup the balance_ctl. CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Qu Wenruo Reviewed-by: Johannes Thumshirn Signed-off-by: Josef Bacik Reviewed-by: David Sterba Signed-off-by: David Sterba diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 2c0aa03b6437..0c7f4f6237e8 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -4318,6 +4318,8 @@ int btrfs_recover_balance(struct btrfs_fs_info *fs_info) btrfs_warn(fs_info, "balance: cannot set exclusive op status, resume manually"); + btrfs_release_path(path); + mutex_lock(&fs_info->balance_mutex); BUG_ON(fs_info->balance_ctl); spin_lock(&fs_info->balance_lock);