241f51931c
This attempts to avoid circular locking dependency between sock_lock and hdev_lock: WARNING: possible circular locking dependency detected 6.0.0-rc7-03728-g18dd8ab0a783 #3 Not tainted ------------------------------------------------------ kworker/u3:2/53 is trying to acquire lock: ffff888000254130 (sk_lock-AF_BLUETOOTH-BTPROTO_ISO){+.+.}-{0:0}, at: iso_conn_del+0xbd/0x1d0 but task is already holding lock: ffffffff9f39a080 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_le_cis_estabilished_evt+0x1b5/0x500 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (hci_cb_list_lock){+.+.}-{3:3}: __mutex_lock+0x10e/0xfe0 hci_le_remote_feat_complete_evt+0x17f/0x320 hci_event_packet+0x39c/0x7d0 hci_rx_work+0x2bf/0x950 process_one_work+0x569/0x980 worker_thread+0x2a3/0x6f0 kthread+0x153/0x180 ret_from_fork+0x22/0x30 -> #1 (&hdev->lock){+.+.}-{3:3}: __mutex_lock+0x10e/0xfe0 iso_connect_cis+0x6f/0x5a0 iso_sock_connect+0x1af/0x710 __sys_connect+0x17e/0x1b0 __x64_sys_connect+0x37/0x50 do_syscall_64+0x43/0x90 entry_SYSCALL_64_after_hwframe+0x62/0xcc -> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_ISO){+.+.}-{0:0}: __lock_acquire+0x1b51/0x33d0 lock_acquire+0x16f/0x3b0 lock_sock_nested+0x32/0x80 iso_conn_del+0xbd/0x1d0 iso_connect_cfm+0x226/0x680 hci_le_cis_estabilished_evt+0x1ed/0x500 hci_event_packet+0x39c/0x7d0 hci_rx_work+0x2bf/0x950 process_one_work+0x569/0x980 worker_thread+0x2a3/0x6f0 kthread+0x153/0x180 ret_from_fork+0x22/0x30 other info that might help us debug this: Chain exists of: sk_lock-AF_BLUETOOTH-BTPROTO_ISO --> &hdev->lock --> hci_cb_list_lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(hci_cb_list_lock); lock(&hdev->lock); lock(hci_cb_list_lock); lock(sk_lock-AF_BLUETOOTH-BTPROTO_ISO); *** DEADLOCK *** 4 locks held by kworker/u3:2/53: #0: ffff8880021d9130 ((wq_completion)hci0#2){+.+.}-{0:0}, at: process_one_work+0x4ad/0x980 #1: ffff888002387de0 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0}, at: process_one_work+0x4ad/0x980 #2: ffff888001ac0070 (&hdev->lock){+.+.}-{3:3}, at: hci_le_cis_estabilished_evt+0xc3/0x500 #3: ffffffff9f39a080 (hci_cb_list_lock){+.+.}-{3:3}, at: hci_le_cis_estabilished_evt+0x1b5/0x500 Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
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.