be4edd1642
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 <ernesto.mnd.fernandez@gmail.com> Signed-off-by: Chao Yu <chao@kernel.org> Link: https://lore.kernel.org/r/20240607142304.455441-1-chao@kernel.org Signed-off-by: Christian Brauner <brauner@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.