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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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Luiz Augusto von Dentz
975abc0c90
This attempts to fix the following trace:
======================================================
WARNING: possible circular locking dependency detected
6.3.0-rc2-g68fcb3a7bf97 #4706 Not tainted
------------------------------------------------------
sco-tester/31 is trying to acquire lock:
ffff8880025b8070 (&hdev->lock){+.+.}-{3:3}, at:
sco_sock_getsockopt+0x1fc/0xa90
but task is already holding lock:
ffff888001eeb130 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at:
sco_sock_getsockopt+0x104/0xa90
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}:
lock_sock_nested+0x32/0x80
sco_connect_cfm+0x118/0x4a0
hci_sync_conn_complete_evt+0x1e6/0x3d0
hci_event_packet+0x55c/0x7c0
hci_rx_work+0x34c/0xa00
process_one_work+0x575/0x910
worker_thread+0x89/0x6f0
kthread+0x14e/0x180
ret_from_fork+0x2b/0x50
-> #1 (hci_cb_list_lock){+.+.}-{3:3}:
__mutex_lock+0x13b/0xcc0
hci_sync_conn_complete_evt+0x1ad/0x3d0
hci_event_packet+0x55c/0x7c0
hci_rx_work+0x34c/0xa00
process_one_work+0x575/0x910
worker_thread+0x89/0x6f0
kthread+0x14e/0x180
ret_from_fork+0x2b/0x50
-> #0 (&hdev->lock){+.+.}-{3:3}:
__lock_acquire+0x18cc/0x3740
lock_acquire+0x151/0x3a0
__mutex_lock+0x13b/0xcc0
sco_sock_getsockopt+0x1fc/0xa90
__sys_getsockopt+0xe9/0x190
__x64_sys_getsockopt+0x5b/0x70
do_syscall_64+0x42/0x90
entry_SYSCALL_64_after_hwframe+0x70/0xda
other info that might help us debug this:
Chain exists of:
&hdev->lock --> hci_cb_list_lock --> sk_lock-AF_BLUETOOTH-BTPROTO_SCO
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(sk_lock-AF_BLUETOOTH-BTPROTO_SCO);
lock(hci_cb_list_lock);
lock(sk_lock-AF_BLUETOOTH-BTPROTO_SCO);
lock(&hdev->lock);
*** DEADLOCK ***
1 lock held by sco-tester/31:
#0: ffff888001eeb130 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0},
at: sco_sock_getsockopt+0x104/0xa90
Fixes: 248733e87d ("Bluetooth: Allow querying of supported offload codecs over SCO socket")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Linux kernel
============
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In order to build the documentation, use ``make htmldocs`` or
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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
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the problems which may result by upgrading your kernel.