Package: src:linux Version: 6.12.101-1 Severity: important Tags: upstream Dear Maintainer,
*** Summary *** Under high-concurrency HTTPS/TLS traffic (such as multi-threaded web scraping or parallel asset downloads), the Intel AC 9560 CNVi wireless interface triggers a hardware microcode stall that deadlocks the internal PCH chipset ring bus on Intel 12th Gen (Alder Lake-P) platforms. *** Symptoms & Absence of Crash Logs *** - Sudden, instantaneous hard system lockup accompanied by a rhythmically blinking Caps Lock LED. - IMPORTANT: No kernel panic backtrace, oops, or kdump vmcore is written to disk because the sudden freeze deadlocks the internal motherboard PCH bus, freezing NVMe DMA write transactions before the kernel can flush the crash logs. - Both software watchdogs (nmi_watchdog=1, hardlockup_panic=1) and hardware watchdogs (iTCO_wdt nowayout=1) fail to trigger an automatic platform reboot due to the PCH bus lockup. - Hardware integrity was thoroughly ruled out: Memtest86+ v7.20 completed 7 full passes (0 errors across 16GB RAM) and sustained 100% CPU load across all 12 cores held steady at 62°C without any throttling; the issue reproduces strictly under multi-stream network traffic over iwlwifi. *** Hardware & Environment *** System: Advan WorkPro Laptop CPU: 12th Gen Intel Core i3-1220P (Alder Lake-P hybrid 2P+8E, 12T) Kernel: Linux workpro 6.12.101+deb13-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.12.101-1 (2026-08-05) x86_64 GNU/Linux OS: Debian GNU/Linux 13 (Trixie) [13.0] Installation: Fresh, clean Debian 13 installation (a few days old, official Debian repositories only) Wireless Device: 00:14.3 Network controller [0280]: Intel Corporation Alder Lake-P PCH CNVi WiFi [8086:51f0] (rev 01) DeviceName: Onboard - Ethernet Subsystem: Intel Corporation Dual Band Wi-Fi 5(802.11ac) Wireless-AC 9560 160MHz 2x2 [Jefferson Peak] [8086:0034] Kernel driver in use: iwlwifi Kernel modules: iwlwifi *** Pre-Freeze Diagnostic Log Snippets (Captured from Prior Boot Initializations) *** iwlwifi 0000:00:14.3: Detected Intel(R) Wireless-AC 9560 160MHz iwlwifi 0000:00:14.3: firmware: failed to load iwlwifi-so-a0-jf-b0-89.ucode down to 80 (-2 Not Found) iwlwifi 0000:00:14.3: loaded fallback firmware iwlwifi-so-a0-jf-b0-77.ucode iwlwifi 0000:00:14.3: 0x00000084 | NMI_INTERRUPT_UNKNOWN iwlwifi 0000:00:14.3: timeout waiting for FW reset ACK (inta_hw=0x0) iwlwifi 0000:00:14.3: Failed to start RT ucode: -110 *** Root Cause & Verified Workaround *** 1. Upgraded to firmware-iwlwifi 20260622-1~bpo13+1 from trixie-backports. 2. Configured /etc/modprobe.d/iwlwifi.conf: options iwlwifi power_save=0 11n_disable=1 options iwlmvm power_scheme=1 With 11n_disable=1, the system successfully completed 200 concurrent TLS streams at 100% throughput with 0 freezes and rock-solid stability. *** Proposed Action for Debian *** 1. Consider backporting firmware-iwlwifi 20260622 into trixie point releases. 2. Document or consider module parameter adjustments (11n_disable=1) for Intel Alder Lake CNVi AC 9560 chipsets to prevent bus deadlocks under high TLS concurrency. -- System Information: Debian Release: 13.0 Architecture: x86_64 Kernel: 6.12.101+deb13-amd64
