[Bug 221103] xhci_hcd: System lockup under CPU load during usbfs polling of USB devices on AMD platforms

[bugzilla-daemon@kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=221103

langosz@gmail.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |langosz@gmail.com

--- Comment #42 from langosz@gmail.com ---
New affected system: ASUS ProArt B850-CREATOR WIFI NEO + Ryzen 7 9700X — total
freeze from adb legacy USB backend polling, no Android device connected

I can confirm this bug on my system. Symptoms are identical to the ones
described here: complete freeze (keyboard dead including SysRq, mouse dead, no
SSH response, display frozen), only a hard reset recovers, and zero kernel logs
— no panic, no soft lockup message, nothing. I had kernel.softlockup_panic=1,
kernel.watchdog_thresh=5, and hung_task_panic=1 enabled with kdump installed
and verified working; the NMI watchdog stayed completely silent and no vmcore
was ever produced, so this is a hard halt below what the kernel can report.

System:

Motherboard: ASUS ProArt B850-CREATOR WIFI NEO (BIOS 1103, 2026-09-18; also
reproduced on BIOS 0239)
CPU: AMD Ryzen 7 9700X (Raphael/Mendocino iGPU driving the display)
GPU: 2× Radeon RX 9060 XT (Navi 44, headless compute via ROCm/llama.cpp)
RAM: 32 GB DDR5-6000 (EXPO enabled)
OS: Ubuntu 26.04.1 LTS, kernel 7.0.0-38-generic (also reproduced on 7.0.0-34
and 7.0.0-14)
Trigger: a resident adb server from android-tools-adb (platform-tools
34.0.5-debian, legacy NATIVE USB backend that polls /dev/bus/usb every second).
Important: no Android device was connected during any of the freezes — the adb
server was simply running in the background after I had used adb devices/adb
logcat, so polling of the root hubs alone was sufficient. The load condition
was sustained CPU/PCIe/memory load from local LLM inference (llama.cpp,
HIP/ROCm backend, both 9060 XTs active). Freezes happened randomly over several
days, always while that workload was running.

USB topology (matches the xHCI superspeed root hub pattern from comment #59):
three 1d6b:0003 Linux Foundation 3.0 root hubs (Bus 2/4/6) plus 2.0 hubs;
attached devices are an IMC Bluetooth radio, an ASUS AURA LED controller
(0b05:19af), a keyboard and a mouse — nothing unusual.

Ruled out on my side: BIOS update 0239 → 1103 (AGESA 1.3.0.1d) did not help;
kernel downgrade to 7.0.0-14 and upgrade to 7.0.0-38 did not help; disabling
EXPO (running at JEDEC speed) did not help — freezes continued, and I have
since re-enabled EXPO with the adb workaround in place and the system remains
stable, so memory speed is not a factor; temperatures normal (37–43 °C); no
MCE/EDAC errors, no PCIe AER errors ever logged.

Workaround: setting ADB_LIBUSB=1 system-wide (forces the libusb backend) — no
freezes for days since, with the same inference workload running, adb
available, and EXPO re-enabled.

-- 
You may reply to this email to add a comment.

You are receiving this mail because:
You are watching the assignee of the bug.