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Yangtao Li 5055b7db94 hfsplus: remove mutex_lock check in hfsplus_free_extents 
[ Upstream commit fcb96956c9 ]

Syzbot reported an issue in hfsplus filesystem:

------------[ cut here ]------------
WARNING: CPU: 0 PID: 4400 at fs/hfsplus/extents.c:346
	hfsplus_free_extents+0x700/0xad0
Call Trace:
<TASK>
hfsplus_file_truncate+0x768/0xbb0 fs/hfsplus/extents.c:606
hfsplus_write_begin+0xc2/0xd0 fs/hfsplus/inode.c:56
cont_expand_zero fs/buffer.c:2383 [inline]
cont_write_begin+0x2cf/0x860 fs/buffer.c:2446
hfsplus_write_begin+0x86/0xd0 fs/hfsplus/inode.c:52
generic_cont_expand_simple+0x151/0x250 fs/buffer.c:2347
hfsplus_setattr+0x168/0x280 fs/hfsplus/inode.c:263
notify_change+0xe38/0x10f0 fs/attr.c:420
do_truncate+0x1fb/0x2e0 fs/open.c:65
do_sys_ftruncate+0x2eb/0x380 fs/open.c:193
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

To avoid deadlock, Commit 31651c6071 ("hfsplus: avoid deadlock
on file truncation") unlock extree before hfsplus_free_extents(),
and add check wheather extree is locked in hfsplus_free_extents().

However, when operations such as hfsplus_file_release,
hfsplus_setattr, hfsplus_unlink, and hfsplus_get_block are executed
concurrently in different files, it is very likely to trigger the
WARN_ON, which will lead syzbot and xfstest to consider it as an
abnormality.

The comment above this warning also describes one of the easy
triggering situations, which can easily trigger and cause
xfstest&syzbot to report errors.

[task A]			[task B]
->hfsplus_file_release
  ->hfsplus_file_truncate
    ->hfs_find_init
      ->mutex_lock
    ->mutex_unlock
				->hfsplus_write_begin
				  ->hfsplus_get_block
				    ->hfsplus_file_extend
				      ->hfsplus_ext_read_extent
				        ->hfs_find_init
					  ->mutex_lock
    ->hfsplus_free_extents
      WARN_ON(mutex_is_locked) !!!

Several threads could try to lock the shared extents tree.
And warning can be triggered in one thread when another thread
has locked the tree. This is the wrong behavior of the code and
we need to remove the warning.

Fixes: 31651c6071 ("hfsplus: avoid deadlock on file truncation")
Reported-by: syzbot+8c0bc9f818702ff75b76@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/00000000000057fa4605ef101c4c@google.com/
Signed-off-by: Yangtao Li <frank.li@vivo.com>
Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>
Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>
Link: https://lore.kernel.org/r/20250529061807.2213498-1-frank.li@vivo.com
Signed-off-by: Viacheslav Dubeyko <slava@dubeyko.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2025-08-15 12:13:32 +02:00
arch KVM: x86: Free vCPUs before freeing VM state 2025-08-01 09:48:47 +01:00
block block: fix kobject leak in blk_unregister_queue 2025-07-24 08:56:30 +02:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: ecdsa - Harden against integer overflows in DIV_ROUND_UP() 2025-07-17 18:37:24 +02:00
Documentation bpf: Adjust free target to avoid global starvation of LRU map 2025-07-17 18:37:22 +02:00
drivers ublk: use vmalloc for ublk_device's __queues 2025-08-15 12:13:32 +02:00
fs hfsplus: remove mutex_lock check in hfsplus_free_extents 2025-08-15 12:13:32 +02:00
include fs_context: fix parameter name in infofc() macro 2025-08-15 12:13:31 +02:00
init rust: clean Rust 1.88.0's unnecessary_transmutes lint 2025-05-18 08:24:51 +02:00
io_uring io_uring/poll: fix POLLERR handling 2025-07-24 08:56:23 +02:00
ipc ipc: fix to protect IPCS lookups using RCU 2025-06-27 11:11:22 +01:00
kernel audit,module: restore audit logging in load failure case 2025-08-15 12:13:31 +02:00
lib lib/alloc_tag: do not acquire non-existent lock in alloc_tag_top_users() 2025-07-17 18:37:14 +02:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm mm: khugepaged: fix call hpage_collapse_scan_file() for anonymous vma 2025-08-01 09:48:47 +01:00
net net/sched: sch_qfq: Avoid triggering might_sleep in atomic context in qfq_delete_class 2025-08-01 09:48:41 +01:00
rust rust: use #[used(compiler)] to fix build and modpost with Rust >= 1.89.0 2025-07-24 08:56:37 +02:00
samples samples/bpf: Fix compilation failure for samples/bpf on LoongArch Fedora 2025-05-29 11:02:01 +02:00
scripts rust: use #[used(compiler)] to fix build and modpost with Rust >= 1.89.0 2025-07-24 08:56:37 +02:00
security selinux: change security_compute_sid to return the ssid or tsid on match 2025-07-10 16:05:04 +02:00
sound ASoC: amd: yc: add DMI quirk for ASUS M6501RM 2025-08-15 12:13:31 +02:00
tools selftests/bpf: Add tests with stack ptr register in conditional jmp 2025-08-01 09:48:44 +01:00
usr kbuild: hdrcheck: fix cross build with clang 2025-03-13 13:02:18 +01:00
virt KVM: Allow CPU to reschedule while setting per-page memory attributes 2025-07-17 18:37:08 +02:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.clippy.toml rust: give Clippy the minimum supported Rust version 2025-08-01 09:48:44 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore rust: introduce .clippy.toml 2025-03-13 13:01:42 +01:00
.mailmap mailmap: add entry for Thorsten Blum 2024-11-07 14:14:59 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Remove self from DSA entry 2024-11-03 12:52:38 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS MAINTAINERS: Update Alexey Makhalov's email address 2025-05-22 14:29:46 +02:00
Makefile Linux 6.12.41 2025-08-01 09:48:47 +01:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

README 

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.