linux/include
Mika Westerberg 96ff396e6e thunderbolt: Use separate lock class for each ring
When connected to another host and then unplugging cable lockdep
triggers following:

 ======================================================
 WARNING: possible circular locking dependency detected
 7.1.0-rc2+ #1775 Tainted: G     U
 ------------------------------------------------------
 kworker/u16:6/312 is trying to acquire lock:
 ffff8881179c70a8 ((work_completion)(&ring->work)){+.+.}-{0:0}, at: __flush_work+0x3cf/0xd10

 but task is already holding lock:
 ffff8881a8b810b0 (&net->connection_lock){+.+.}-{4:4}, at: tbnet_tear_down+0x110/0x720 [thunderbolt_net]

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> #1 (&net->connection_lock){+.+.}-{4:4}:
        __mutex_lock+0x19a/0x2490
        mutex_lock_nested+0x1b/0x30
        tbnet_handle_packet+0x74c/0xd70 [thunderbolt_net]
        tb_xdomain_handle_request+0x37c/0x4b0 [thunderbolt]
        tb_domain_event_cb+0xc9/0x140 [thunderbolt]
        tb_ctl_handle_event+0xd6/0x2c0 [thunderbolt]
        tb_ctl_rx_callback+0x22c/0xa10 [thunderbolt]
        ring_work+0x715/0xcb0 [thunderbolt]
        process_one_work+0x902/0x1790
        worker_thread+0x5cd/0xfe0
        kthread+0x339/0x420
        ret_from_fork+0x79a/0x9d0
        ret_from_fork_asm+0x1a/0x30

 -> #0 ((work_completion)(&ring->work)){+.+.}-{0:0}:
        __lock_acquire+0x1592/0x2640
        lock_acquire+0x1a3/0x300
        __flush_work+0x3e9/0xd10
        flush_work+0x21/0x30
        tb_ring_stop+0x240/0x840 [thunderbolt]
        tbnet_tear_down+0x2ff/0x720 [thunderbolt_net]
        tbnet_stop+0x47/0x1a0 [thunderbolt_net]
        __dev_close_many+0x19e/0x4e0
        netif_close_many+0x1e8/0x640
        unregister_netdevice_many_notify+0x6d3/0x22d0
        unregister_netdevice_queue+0x2b9/0x3a0
        unregister_netdev+0x1c/0x70
        tbnet_remove+0x52/0xb0 [thunderbolt_net]
        tb_service_remove+0x8a/0xe0 [thunderbolt]
        device_remove+0xc5/0x190
        device_release_driver_internal+0x3db/0x590
        device_release_driver+0x12/0x20
        bus_remove_device+0x2c1/0x580
        device_del+0x3d9/0x9f0
        device_unregister+0x17/0xc0
        unregister_service+0x46/0x60 [thunderbolt]
        device_for_each_child_reverse+0xfa/0x180
        tb_xdomain_unregister+0x57/0xe0 [thunderbolt]
        unregister_unplugged_xdomain+0x101/0x1a0 [thunderbolt]
        bus_for_each_dev+0x111/0x1a0
        tb_domain_unregister_unplugged_xdomains+0x98/0xe0 [thunderbolt]
        tb_handle_hotplug+0xc3/0x2bb0 [thunderbolt]
        process_one_work+0x902/0x1790
        worker_thread+0x5cd/0xfe0
        kthread+0x339/0x420
        ret_from_fork+0x79a/0x9d0
        ret_from_fork_asm+0x1a/0x30

 other info that might help us debug this:

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&net->connection_lock);
                                lock((work_completion)(&ring->work));
                                lock(&net->connection_lock);
   lock((work_completion)(&ring->work));

This in fact is false positive because they involve unrelated rings (and
unrelated work structures). In the first one it is ring 0 which is used
for control traffic and in the second it is dealing with another ring
used for the high-speed traffic.

Fix this by using separate lock class for each ring worker.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
2026-09-04 08:28:47 +02:00
..
acpi More ACPI support updates for 7.3-rc1 2026-08-26 14:06:08 -07:00
asm-generic kho: make boot time huge page allocation work nicely with KHO 2026-08-23 09:17:38 -07:00
clocksource hyperv-next for v7.3-rc1 2026-08-26 16:47:40 -07:00
crypto This update includes the following changes: 2026-08-19 17:25:42 -07:00
cxl
drm Linux 7.2 2026-08-20 10:58:44 +10:00
dt-bindings sound fixes for 7.3-rc1 2026-08-28 10:01:02 -07:00
hyperv
keys tpm: Initial step to reorganize TPM public headers 2026-08-25 18:13:35 +03:00
kunit gpio updates for v7.3-rc1 2026-08-19 09:10:07 -07:00
kvm KVM/arm64 changes for 7.3 2026-08-24 12:42:07 -04:00
linux thunderbolt: Use separate lock class for each ring 2026-09-04 08:28:47 +02:00
math-emu
media
memory
misc
net Including fixes from Bluetooth, IPSec and Netfilter. 2026-08-27 13:53:43 -07:00
pcmcia
ras
rdma
rv mm.git review status for linus..mm-stable 2026-08-27 09:17:06 -07:00
scsi SCSI updates for 7.3 2026-08-29 11:55:36 -07:00
soc Mostly the usual clk driver updates and new SoC additions plus non-critical 2026-08-26 11:14:30 -07:00
sound ALSA: rawmidi: Another workaround for false-positive mutex lockdep warning 2026-08-25 15:55:37 +02:00
target usb: gadget: f_tcm: keep port count until LUN teardown completes 2026-08-14 10:49:21 +09:00
trace f2fs-for-7.3-rc1 2026-08-28 10:48:48 -07:00
uapi drm next/fixes for 7.3-rc1 2026-08-28 16:37:55 -07:00
ufs
vdso vDSO: Make clockmode constants available without CONFIG_GENERIC_GETTIMEOFDAY 2026-08-10 16:25:21 +02:00
video fbdev: maxine: fix 64-bit build error 2026-08-20 23:45:07 +02:00
xen
Kbuild