Trying to bring an AX88772B-based USB-Ethernet adapter up results in a
deadlock if the adapter was suspended at the time. Most network-related
software hangs up indefinitely as a result. This can happen on systems
which configure USB power control to 'auto' by default, e.g. laptops
running `tlp`.
Steps to reproduce:
Try to bring the interface up while the adapter is suspended. For
example, assuming that the device is on bus 1, port 1:
root@usb-eth-test:/sys/bus/usb/devices/1-1/power# echo auto > control
root@usb-eth-test:/sys/bus/usb/devices/1-1/power# cat runtime_status
suspended
root@usb-eth-test:/sys/bus/usb/devices/1-1/power# ip link set enp0s1u1 up
Expectations vs reality:
The interface should be brought up and be able to operate, but instead
the `ip` command hangs up and never returns, and lockdep emits the
following warning (decoded here):
============================================
WARNING: possible recursive locking detected
6.17.0-rc3 #1 Not tainted
--------------------------------------------
ip/273 is trying to acquire lock:
ffffffffb906e748 (rtnl_mutex){+.+.}-{4:4}, at: ax88772_resume (drivers/net/usb/asix_devices.c:650)
but task is already holding lock:
ffffffffb906e748 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink (net/core/rtnetlink.c:3893 net/core/rtnetlink.c:4057)
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(rtnl_mutex);
lock(rtnl_mutex);
*** DEADLOCK ***
May be due to missing lock nesting notation
1 lock held by ip/273:
#0: ffffffffb906e748 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink (net/core/rtnetlink.c:3893 net/core/rtnetlink.c:4057)
stack backtrace:
CPU: 0 UID: 0 PID: 273 Comm: ip Not tainted 6.17.0-rc3 #1 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl (lib/dump_stack.c:122)
print_deadlock_bug.cold (kernel/locking/lockdep.c:3044)
__lock_acquire (kernel/locking/lockdep.c:3897 kernel/locking/lockdep.c:5237)
? usb_start_wait_urb (drivers/usb/core/message.c:83)
lock_acquire (kernel/locking/lockdep.c:470 (discriminator 4) kernel/locking/lockdep.c:5870 (discriminator 4) kernel/locking/lockdep.c:5825 (discriminator 4))
? ax88772_resume (drivers/net/usb/asix_devices.c:650)
__mutex_lock (arch/x86/include/asm/jump_label.h:36 include/trace/events/lock.h:95 kernel/locking/mutex.c:600 kernel/locking/mutex.c:760)
? ax88772_resume (drivers/net/usb/asix_devices.c:650)
? ax88772_resume (drivers/net/usb/asix_devices.c:650)
? __usbnet_read_cmd (drivers/net/usb/usbnet.c:2065)
? ax88772_resume (drivers/net/usb/asix_devices.c:650)
? srso_alias_return_thunk (arch/x86/lib/retpoline.S:183)
ax88772_resume (drivers/net/usb/asix_devices.c:650)
asix_resume (drivers/net/usb/asix_devices.c:663)
usb_resume_interface.isra.0 (drivers/usb/core/driver.c:1375)
usb_resume_both (drivers/usb/core/driver.c:1532 (discriminator 1))
? __pfx_usb_runtime_resume (drivers/usb/core/driver.c:1981)
__rpm_callback (drivers/base/power/runtime.c:406)
? srso_alias_return_thunk (arch/x86/lib/retpoline.S:183)
? srso_alias_return_thunk (arch/x86/lib/retpoline.S:183)
rpm_callback (include/linux/sched/mm.h:339 (discriminator 1) include/linux/sched/mm.h:369 (discriminator 1) drivers/base/power/runtime.c:458 (discriminator 1))
? __pfx_usb_runtime_resume (drivers/usb/core/driver.c:1981)
rpm_resume (drivers/base/power/runtime.c:934)
? srso_alias_return_thunk (arch/x86/lib/retpoline.S:183)
? lock_release (kernel/locking/lockdep.c:5536 kernel/locking/lockdep.c:5889 kernel/locking/lockdep.c:5875)
rpm_resume (drivers/base/power/runtime.c:913)
__pm_runtime_resume (include/linux/spinlock.h:406 drivers/base/power/runtime.c:1193)
usb_autopm_get_interface (include/linux/pm_runtime.h:532 drivers/usb/core/driver.c:1828)
usbnet_open (drivers/net/usb/usbnet.c:899)
__dev_open (net/core/dev.c:1684)
__dev_change_flags (net/core/dev.c:9549)
netif_change_flags (net/core/dev.c:9612)
do_setlink.isra.0 (net/core/rtnetlink.c:3143 (discriminator 1))
? lock_release (kernel/locking/lockdep.c:5536 kernel/locking/lockdep.c:5889 kernel/locking/lockdep.c:5875)
? rtnl_newlink (net/core/rtnetlink.c:3893 net/core/rtnetlink.c:4057)
? srso_alias_return_thunk (arch/x86/lib/retpoline.S:183)
? __mutex_lock (include/trace/events/lock.h:122 (discriminator 2) kernel/locking/mutex.c:607 (discriminator 2) kernel/locking/mutex.c:760 (discriminator 2))
? srso_alias_return_thunk (arch/x86/lib/retpoline.S:183)
? rtnl_newlink (net/core/rtnetlink.c:3893 net/core/rtnetlink.c:4057)
? lock_release (kernel/locking/lockdep.c:5536 kernel/locking/lockdep.c:5889 kernel/locking/lockdep.c:5875)
rtnl_newlink (net/core/rtnetlink.c:3761 (discriminator 1) net/core/rtnetlink.c:3920 (discriminator 1) net/core/rtnetlink.c:4057 (discriminator 1))
? lock_acquire (kernel/locking/lockdep.c:470 (discriminator 4) kernel/locking/lockdep.c:5870 (discriminator 4) kernel/locking/lockdep.c:5825 (discriminator 4))
? srso_alias_return_thunk (arch/x86/lib/retpoline.S:183)
? find_held_lock (kernel/locking/lockdep.c:5350 (discriminator 1))
? rtnetlink_rcv_msg (include/linux/rcupdate.h:341 (discriminator 1) include/linux/rcupdate.h:871 (discriminator 1) net/core/rtnetlink.c:6944 (discriminator 1))
? __pfx_rtnl_newlink (net/core/rtnetlink.c:3948)
? srso_alias_return_thunk (arch/x86/lib/retpoline.S:183)
? rtnetlink_rcv_msg (net/core/rtnetlink.c:6945)
? srso_alias_return_thunk (arch/x86/lib/retpoline.S:183)
? __pfx_rtnetlink_rcv_msg (net/core/rtnetlink.c:6849)
netlink_rcv_skb (net/netlink/af_netlink.c:2552)
netlink_unicast (net/netlink/af_netlink.c:1321 net/netlink/af_netlink.c:1346)
netlink_sendmsg (net/netlink/af_netlink.c:1896)
____sys_sendmsg (net/socket.c:714 (discriminator 1) net/socket.c:729 (discriminator 1) net/socket.c:2614 (discriminator 1))
___sys_sendmsg (net/socket.c:2670)
? lock_release (kernel/locking/lockdep.c:5536 kernel/locking/lockdep.c:5889 kernel/locking/lockdep.c:5875)
__sys_sendmsg (net/socket.c:2700 (discriminator 1))
? srso_alias_return_thunk (arch/x86/lib/retpoline.S:183)
do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1))
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
RIP: 0033:0x7fddcbcb2687
Code: 48 89 fa 4c 89 df e8 58 b3 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
All code
========
0: 48 89 fa mov %rdi,%rdx
3: 4c 89 df mov %r11,%rdi
6: e8 58 b3 00 00 call 0xb363
b: 8b 93 08 03 00 00 mov 0x308(%rbx),%edx
11: 59 pop %rcx
12: 5e pop %rsi
13: 48 83 f8 fc cmp $0xfffffffffffffffc,%rax
17: 74 1a je 0x33
19: 5b pop %rbx
1a: c3 ret
1b: 0f 1f 84 00 00 00 00 nopl 0x0(%rax,%rax,1)
22: 00
23: 48 8b 44 24 10 mov 0x10(%rsp),%rax
28: 0f 05 syscall
2a:* 5b pop %rbx <-- trapping instruction
2b: c3 ret
2c: 0f 1f 80 00 00 00 00 nopl 0x0(%rax)
33: 83 e2 39 and $0x39,%edx
36: 83 fa 08 cmp $0x8,%edx
39: 75 de jne 0x19
3b: e8 23 ff ff ff call 0xffffffffffffff63
Code starting with the faulting instruction
===========================================
0: 5b pop %rbx
1: c3 ret
2: 0f 1f 80 00 00 00 00 nopl 0x0(%rax)
9: 83 e2 39 and $0x39,%edx
c: 83 fa 08 cmp $0x8,%edx
f: 75 de jne 0xffffffffffffffef
11: e8 23 ff ff ff call 0xffffffffffffff39
RSP: 002b:00007fffad1c7b60 EFLAGS: 00000202 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fddcba85840 RCX: 00007fddcbcb2687
RDX: 0000000000000000 RSI: 00007fffad1c7c10 RDI: 0000000000000003
RBP: 00007fffad1c7c10 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00007fffad1c8300
R13: 0000000000000000 R14: 0000555b0fa13020 R15: 0000000000000000
</TASK>
Details:
I have used QEMU with USB passthrough to catch the issue, but this
happens on real hardware as well.
The bug has already been reported on bugzilla
(https://bugzilla.kernel.org/show_bug.cgi?id=215199), but this was
probably not the right place.
USB device: Edimax USB 2.0 Fast Ethernet Adapter, model no. EU-4208
USB device IDs: 0b95:772b ASIX Electronics Corp. AX88772B
Kernel version (/proc/version):
Linux version 6.17.0-rc3 (hubert25632@B550M-AE) (gcc (Debian 14.2.0-19)
14.2.0, GNU ld (GNU Binutils for Debian) 2.44) #1 SMP PREEMPT_DYNAMIC
Sat Aug 30 21:43:30 CEST 2025
iproute2 version: ip utility, iproute2-6.16.0, libbpf 1.6.2
OS: Debian GNU/Linux forky/sid
CPU architecture: x86_64
Kernel config: https://pastebin.com/MiBZnCgC
dmesg log: https://pastebin.com/JXiZTiAT
Last good kernel version: v5.13
First bad commit: 4a2c7217cd5a ("net: usb: asix: ax88772: manage PHY PM from MAC")
Possible workaroud:
Users of `tlp` can add the following statement to `/etc/tlp.conf` to
prevent the adapter from being suspended automatically:
USB_DENYLIST="0b95:772b"
#regzbot introduced: 4a2c7217cd5a
