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7fe3556f98
[ Upstream commit 769bf60e17ee1a56a81e7c031192c3928312c52e ]
syzbot found a potential circular dependency leading to a deadlock:
-> #3 (&hdev->req_lock){+.+.}-{3:3}:
__mutex_lock_common+0x1b6/0x1bc2 kernel/locking/mutex.c:599
__mutex_lock kernel/locking/mutex.c:732 [inline]
mutex_lock_nested+0x17/0x1c kernel/locking/mutex.c:784
hci_dev_do_close+0x3f/0x9f net/bluetooth/hci_core.c:551
hci_rfkill_set_block+0x130/0x1ac net/bluetooth/hci_core.c:935
rfkill_set_block+0x1e6/0x3b8 net/rfkill/core.c:345
rfkill_fop_write+0x2d8/0x672 net/rfkill/core.c:1274
vfs_write+0x277/0xcf5 fs/read_write.c:594
ksys_write+0x19b/0x2bd fs/read_write.c:650
do_syscall_x64 arch/x86/entry/common.c:55 [inline]
do_syscall_64+0x51/0xba arch/x86/entry/common.c:93
entry_SYSCALL_64_after_hwframe+0x61/0xcb
-> #2 (rfkill_global_mutex){+.+.}-{3:3}:
__mutex_lock_common+0x1b6/0x1bc2 kernel/locking/mutex.c:599
__mutex_lock kernel/locking/mutex.c:732 [inline]
mutex_lock_nested+0x17/0x1c kernel/locking/mutex.c:784
rfkill_register+0x30/0x7e3 net/rfkill/core.c:1045
hci_register_dev+0x48f/0x96d net/bluetooth/hci_core.c:2622
__vhci_create_device drivers/bluetooth/hci_vhci.c:341 [inline]
vhci_create_device+0x3ad/0x68f drivers/bluetooth/hci_vhci.c:374
vhci_get_user drivers/bluetooth/hci_vhci.c:431 [inline]
vhci_write+0x37b/0x429 drivers/bluetooth/hci_vhci.c:511
call_write_iter include/linux/fs.h:2109 [inline]
new_sync_write fs/read_write.c:509 [inline]
vfs_write+0xaa8/0xcf5 fs/read_write.c:596
ksys_write+0x19b/0x2bd fs/read_write.c:650
do_syscall_x64 arch/x86/entry/common.c:55 [inline]
do_syscall_64+0x51/0xba arch/x86/entry/common.c:93
entry_SYSCALL_64_after_hwframe+0x61/0xcb
-> #1 (&data->open_mutex){+.+.}-{3:3}:
__mutex_lock_common+0x1b6/0x1bc2 kernel/locking/mutex.c:599
__mutex_lock kernel/locking/mutex.c:732 [inline]
mutex_lock_nested+0x17/0x1c kernel/locking/mutex.c:784
vhci_send_frame+0x68/0x9c drivers/bluetooth/hci_vhci.c:75
hci_send_frame+0x1cc/0x2ff net/bluetooth/hci_core.c:2989
hci_sched_acl_pkt net/bluetooth/hci_core.c:3498 [inline]
hci_sched_acl net/bluetooth/hci_core.c:3583 [inline]
hci_tx_work+0xb94/0x1a60 net/bluetooth/hci_core.c:3654
process_one_work+0x901/0xfb8 kernel/workqueue.c:2310
worker_thread+0xa67/0x1003 kernel/workqueue.c:2457
kthread+0x36a/0x430 kernel/kthread.c:319
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298
-> #0 ((work_completion)(&hdev->tx_work)){+.+.}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain kernel/locking/lockdep.c:3787 [inline]
__lock_acquire+0x2d32/0x77fa kernel/locking/lockdep.c:5011
lock_acquire+0x273/0x4d5 kernel/locking/lockdep.c:5622
__flush_work+0xee/0x19f kernel/workqueue.c:3090
hci_dev_close_sync+0x32f/0x1113 net/bluetooth/hci_sync.c:4352
hci_dev_do_close+0x47/0x9f net/bluetooth/hci_core.c:553
hci_rfkill_set_block+0x130/0x1ac net/bluetooth/hci_core.c:935
rfkill_set_block+0x1e6/0x3b8 net/rfkill/core.c:345
rfkill_fop_write+0x2d8/0x672 net/rfkill/core.c:1274
vfs_write+0x277/0xcf5 fs/read_write.c:594
ksys_write+0x19b/0x2bd fs/read_write.c:650
do_syscall_x64 arch/x86/entry/common.c:55 [inline]
do_syscall_64+0x51/0xba arch/x86/entry/common.c:93
entry_SYSCALL_64_after_hwframe+0x61/0xcb
This change removes the need for acquiring the open_mutex in
vhci_send_frame, thus eliminating the potential deadlock while
maintaining the required packet ordering.
Fixes: 92d4abd66f ("Bluetooth: vhci: Fix race when opening vhci device")
Signed-off-by: Ying Hsu <yinghsu@chromium.org>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Sasha Levin <sashal@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 Restructured Text 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.