From patchwork Fri Jun 7 14:23:04 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Chao Yu X-Patchwork-Id: 13690136 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 321251DFC5; Fri, 7 Jun 2024 14:23:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717770202; cv=none; b=lzMowhnOa4pSLMbhKOeuX8qs6B/naL0MfDHJmYUuG8sr5rH2kUhLwjcYBz/i2u68XsgGp/x3SEoCh9aeuAZlp3zdP6/S2NvPQ4G12tJcKf9zWz5DAzmXPOJGc6wY9iQ6zT1JSbLmPHSkmwNvrXTM/FhK/fvS2l8yBky3UW0Wph0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1717770202; c=relaxed/simple; bh=jC5KdN3iR66YvPbVE6j7MiDgwoUQwI/b2jmyTOxWUZM=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version:Content-Type; b=C3vVZ4o8s7LZwSjIX3kBvQ/gVcMaOAIYobk78LtKpCcSF24diBjlS5toP8LA7tEpD2I4THgReRSvEuOCFBs+I4h1V+2povW9tNMPvsAf5TTnI6AgaNM+GyWsO67Vy08zR8vtNqv1qtzMWVm07QpTsG49KQ9xMklXowxePhWcDvo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=YVQipCbX; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="YVQipCbX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A1D01C3277B; Fri, 7 Jun 2024 14:23:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1717770201; bh=jC5KdN3iR66YvPbVE6j7MiDgwoUQwI/b2jmyTOxWUZM=; h=From:To:Cc:Subject:Date:From; b=YVQipCbXj8ZWfuh9XDXy4PtL2n3Pwamllb20cQCA4OqNqNu/oeYyuYuHLVcvtk7hf uHeNa9Evpd1XlA6IoPmKE+Ne7SwYP18IeJsYM2/0O9wSsoQU15xK/BmCM0+b0/K4T2 O6xK0wu51raZEzWmmWJySk1VIbdSN2rBMdBWfDKnaKKkVR0gGp9/WplYKZkmMThFBi MT3w9tOSeJI+eS/ZnAZ3OoRXRF5SfuHTg0e15IPGi3j2tsWenpDMjJYaWvAAc3tJzM nrShddaLoJ8yt39DTgrwbEbU4hUx1pIQy6fc2oBCDWleHgCAfI/0hOZQYs6wd+tqcp P0I5X6H3uuOfQ== From: Chao Yu To: akpm@linux-foundation.org, viro@zeniv.linux.org.uk, brauner@kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Chao Yu , syzbot+6030b3b1b9bf70e538c4@syzkaller.appspotmail.com, =?utf-8?q?Ernesto_A_?= =?utf-8?q?=2E_Fern=C3=A1ndez?= Subject: [PATCH] hfsplus: fix to avoid false alarm of circular locking Date: Fri, 7 Jun 2024 22:23:04 +0800 Message-Id: <20240607142304.455441-1-chao@kernel.org> X-Mailer: git-send-email 2.40.1 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Syzbot report potential ABBA deadlock as below: loop0: detected capacity change from 0 to 1024 ====================================================== WARNING: possible circular locking dependency detected 6.9.0-syzkaller-10323-g8f6a15f095a6 #0 Not tainted ------------------------------------------------------ syz-executor171/5344 is trying to acquire lock: ffff88807cb980b0 (&tree->tree_lock){+.+.}-{3:3}, at: hfsplus_file_truncate+0x811/0xb50 fs/hfsplus/extents.c:595 but task is already holding lock: ffff88807a930108 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_file_truncate+0x2da/0xb50 fs/hfsplus/extents.c:576 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752 hfsplus_file_extend+0x21b/0x1b70 fs/hfsplus/extents.c:457 hfsplus_bmap_reserve+0x105/0x4e0 fs/hfsplus/btree.c:358 hfsplus_rename_cat+0x1d0/0x1050 fs/hfsplus/catalog.c:456 hfsplus_rename+0x12e/0x1c0 fs/hfsplus/dir.c:552 vfs_rename+0xbdb/0xf00 fs/namei.c:4887 do_renameat2+0xd94/0x13f0 fs/namei.c:5044 __do_sys_rename fs/namei.c:5091 [inline] __se_sys_rename fs/namei.c:5089 [inline] __x64_sys_rename+0x86/0xa0 fs/namei.c:5089 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&tree->tree_lock){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3134 [inline] check_prevs_add kernel/locking/lockdep.c:3253 [inline] validate_chain+0x18cb/0x58e0 kernel/locking/lockdep.c:3869 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 __mutex_lock_common kernel/locking/mutex.c:608 [inline] __mutex_lock+0x136/0xd70 kernel/locking/mutex.c:752 hfsplus_file_truncate+0x811/0xb50 fs/hfsplus/extents.c:595 hfsplus_setattr+0x1ce/0x280 fs/hfsplus/inode.c:265 notify_change+0xb9d/0xe70 fs/attr.c:497 do_truncate+0x220/0x310 fs/open.c:65 handle_truncate fs/namei.c:3308 [inline] do_open fs/namei.c:3654 [inline] path_openat+0x2a3d/0x3280 fs/namei.c:3807 do_filp_open+0x235/0x490 fs/namei.c:3834 do_sys_openat2+0x13e/0x1d0 fs/open.c:1406 do_sys_open fs/open.c:1421 [inline] __do_sys_creat fs/open.c:1497 [inline] __se_sys_creat fs/open.c:1491 [inline] __x64_sys_creat+0x123/0x170 fs/open.c:1491 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&HFSPLUS_I(inode)->extents_lock); lock(&tree->tree_lock); lock(&HFSPLUS_I(inode)->extents_lock); lock(&tree->tree_lock); This is a false alarm as tree_lock mutex are different, one is from sbi->cat_tree, and another is from sbi->ext_tree: Thread A Thread B - hfsplus_rename - hfsplus_rename_cat - hfs_find_init - mutext_lock(cat_tree->tree_lock) - hfsplus_setattr - hfsplus_file_truncate - mutex_lock(hip->extents_lock) - hfs_find_init - mutext_lock(ext_tree->tree_lock) - hfs_bmap_reserve - hfsplus_file_extend - mutex_lock(hip->extents_lock) So, let's call mutex_lock_nested for tree_lock mutex lock, and pass correct lock class for it. Fixes: 31651c607151 ("hfsplus: avoid deadlock on file truncation") Reported-by: syzbot+6030b3b1b9bf70e538c4@syzkaller.appspotmail.com Closes: https://lore.kernel.org/linux-fsdevel/000000000000e37a4005ef129563@google.com Cc: Ernesto A. Fernández Signed-off-by: Chao Yu --- fs/hfsplus/bfind.c | 15 ++------------- fs/hfsplus/extents.c | 9 ++++++--- fs/hfsplus/hfsplus_fs.h | 21 +++++++++++++++++++++ 3 files changed, 29 insertions(+), 16 deletions(-) diff --git a/fs/hfsplus/bfind.c b/fs/hfsplus/bfind.c index ca2ba8c9f82e..901e83d65d20 100644 --- a/fs/hfsplus/bfind.c +++ b/fs/hfsplus/bfind.c @@ -25,19 +25,8 @@ int hfs_find_init(struct hfs_btree *tree, struct hfs_find_data *fd) fd->key = ptr + tree->max_key_len + 2; hfs_dbg(BNODE_REFS, "find_init: %d (%p)\n", tree->cnid, __builtin_return_address(0)); - switch (tree->cnid) { - case HFSPLUS_CAT_CNID: - mutex_lock_nested(&tree->tree_lock, CATALOG_BTREE_MUTEX); - break; - case HFSPLUS_EXT_CNID: - mutex_lock_nested(&tree->tree_lock, EXTENTS_BTREE_MUTEX); - break; - case HFSPLUS_ATTR_CNID: - mutex_lock_nested(&tree->tree_lock, ATTR_BTREE_MUTEX); - break; - default: - BUG(); - } + mutex_lock_nested(&tree->tree_lock, + hfsplus_btree_lock_class(tree)); return 0; } diff --git a/fs/hfsplus/extents.c b/fs/hfsplus/extents.c index 3c572e44f2ad..9c51867dddc5 100644 --- a/fs/hfsplus/extents.c +++ b/fs/hfsplus/extents.c @@ -430,7 +430,8 @@ int hfsplus_free_fork(struct super_block *sb, u32 cnid, hfsplus_free_extents(sb, ext_entry, total_blocks - start, total_blocks); total_blocks = start; - mutex_lock(&fd.tree->tree_lock); + mutex_lock_nested(&fd.tree->tree_lock, + hfsplus_btree_lock_class(fd.tree)); } while (total_blocks > blocks); hfs_find_exit(&fd); @@ -592,7 +593,8 @@ void hfsplus_file_truncate(struct inode *inode) alloc_cnt, alloc_cnt - blk_cnt); hfsplus_dump_extent(hip->first_extents); hip->first_blocks = blk_cnt; - mutex_lock(&fd.tree->tree_lock); + mutex_lock_nested(&fd.tree->tree_lock, + hfsplus_btree_lock_class(fd.tree)); break; } res = __hfsplus_ext_cache_extent(&fd, inode, alloc_cnt); @@ -606,7 +608,8 @@ void hfsplus_file_truncate(struct inode *inode) hfsplus_free_extents(sb, hip->cached_extents, alloc_cnt - start, alloc_cnt - blk_cnt); hfsplus_dump_extent(hip->cached_extents); - mutex_lock(&fd.tree->tree_lock); + mutex_lock_nested(&fd.tree->tree_lock, + hfsplus_btree_lock_class(fd.tree)); if (blk_cnt > start) { hip->extent_state |= HFSPLUS_EXT_DIRTY; break; diff --git a/fs/hfsplus/hfsplus_fs.h b/fs/hfsplus/hfsplus_fs.h index 012a3d003fbe..9e78f181c24f 100644 --- a/fs/hfsplus/hfsplus_fs.h +++ b/fs/hfsplus/hfsplus_fs.h @@ -553,6 +553,27 @@ static inline __be32 __hfsp_ut2mt(time64_t ut) return cpu_to_be32(lower_32_bits(ut) + HFSPLUS_UTC_OFFSET); } +static inline enum hfsplus_btree_mutex_classes +hfsplus_btree_lock_class(struct hfs_btree *tree) +{ + enum hfsplus_btree_mutex_classes class; + + switch (tree->cnid) { + case HFSPLUS_CAT_CNID: + class = CATALOG_BTREE_MUTEX; + break; + case HFSPLUS_EXT_CNID: + class = EXTENTS_BTREE_MUTEX; + break; + case HFSPLUS_ATTR_CNID: + class = ATTR_BTREE_MUTEX; + break; + default: + BUG(); + } + return class; +} + /* compatibility */ #define hfsp_mt2ut(t) (struct timespec64){ .tv_sec = __hfsp_mt2ut(t) } #define hfsp_ut2mt(t) __hfsp_ut2mt((t).tv_sec)