** Description changed: ############ Summary ############ Running modern Windows games through Steam Proton (DXVK/vkd3d) on Ubuntu 24.04–based Linux Mint consistently triggers kernel oopses in: syscall_exit_to_user_mode (NULL pointer dereference) fpregs_assert_state_consistent (FPU state inconsistency) and previously, on a mainline kernel, amdgpu_hmm_range_get_pages (bad page map) These occur across multiple games, not tied to a specific title, and only under Proton workloads. Hardware stress tests show no instability, suggesting a kernel regression. The same hardware with a separate harddrive running windows, has no issues. ############ System Information ############ Distro: Linux Mint 22.x (Ubuntu 24.04 base) Kernel (affected): 6.14.0-37-generic #37~24.04.1-Ubuntu Also tested: 6.18.1-061801-generic (mainline, not Ubuntu-supported), 6.6.0-060600, 6.7.0-060700, 6.8.0-90 Motherboard: Gigabyte Z790 UD AC BIOS: F14 (09/18/2025) CPU: [Insert output of lscpu | grep 'Model name'] GPU: AMD Radeon RX 7900 XTX Driver: in‑kernel amdgpu (no proprietary modules) Taint flags: G D W after oops (no out‑of‑tree modules) I can attach full outputs of uname -a, lspci -nn, and lsmod if needed. ############ Description of the Problem ############ When running Proton-based games (DX12/DXVK/vkd3d), the kernel intermittently logs: 1. NULL pointer dereference in syscall_exit_to_user_mode Example from Europa Universalis V: #LOG# BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode Oops: 0000 [#2] PREEMPT SMP NOPTI CPU: 5 PID: 15370 Comm: Task_P_BN 1 Tainted: G D W 6.14.0-37-generic RIP: 0010:syscall_exit_to_user_mode+0x74/0x1d0 ... note: Task_P_BN 1 exited with irqs disabled #ENDLOG# This same oops occurred earlier with a different Proton thread (ThreadPoolForeg), same kernel, same RIP offset. 2. FPU state inconsistency warning in DXVK shader worker #LOG# WARNING: CPU: 4 PID: 8329 at arch/x86/kernel/fpu/core.c:822 fpregs_assert_state_consistent+0x2d/0x50 Comm: dxvk-shader-n Tainted: G D 6.14.0-37-generic Call Trace: - arch_exit_to_user_mode_prepare - irqentry_exit_to_user_mode - sysvec_reschedule_ipi + arch_exit_to_user_mode_prepare + irqentry_exit_to_user_mode + sysvec_reschedule_ipi #ENDLOG# This appears during shader compilation under DXVK. 3. On mainline kernel 6.18.1: amdgpu HMM page map corruption #LOG# BUG: Bad page map in process vkd3d_queue amdgpu_hmm_range_get_pages amdgpu_ttm_tt_get_user_pages amdgpu_cs_ioctl #ENDLOG# To me this might suggest a second failure mode in GPU memory management under vkd3d. - ############ Workloads That Trigger the Bug ############ Arc Raiders (Unreal Engine 5, DX12 via Proton) Europa Universalis V (DX11/DX12 via Proton) Both games trigger oopses within minutes. And multiple other games, the issue is not game-specific. ############ Steps to Reproduce ############ Boot into kernel 6.14.0-37-generic. Start dmesg -w in a terminal. Launch Steam → run a Proton game (Arc Raiders or EU5). Play or idle for a few minutes. Observe kernel oopses in syscall_exit_to_user_mode or FPU warnings. Repro rate: high (multiple times per session). ############ Hardware Stability Verification ############ - To rule out hardware faults: - I tested on windows which was installed on a separate drive completely, and had no issues playing games or running benchmarks and no pixel artifact + I tested on windows which was installed on a separate drive completely, and had no issues playing games or running benchmarks and no pixel artifact. I also reseated the GPU and confirmed it was using 3 independent power cables to the PSU I ran memtester (4 GB locked, multiple loops) All tests passed (stuck address, random value, bit fade, etc.) and ran stress-ng (30 minutes) Command: Code stress-ng --cpu 8 --matrix 4 --vecmath 4 --timeout 30m --metrics-brief Heavy CPU/FPU/AVX/SIMD load No errors, kernel warnings and no thermal throttling or instability in dmesg. To me this suggests the kernel oopses are not hardware-related. ############ Expected Behavior ############ Proton games should run without triggering kernel oopses in: syscall exit path FPU state handling amdgpu HMM ############ Actual Behavior ############ Kernel logs fatal oopses Threads exit with IRQs disabled Kernel becomes tainted Games may crash or behave unpredictably System remains running but in an unsafe state, have ran into two kernel panics, and were not able to grab logs. ############ Additional Notes ############ - + No proprietary modules loaded No overclocking; system at stock settings Issue reproduced across multiple Proton versions Issue reproduced across multiple games Issue reproduced across multiple kernels (Ubuntu + mainline) No errors under synthetic stress tests ############ Conclusion ############ I've been racking my head on this for about a week now on a fresh Mint install, I wasn't sure where to submit this bug report but thought it might be a good idea to run it by you guys to see if this is the right place to report it. From my (limited) understanding, this appears to be a kernel regression affecting: x86 syscall exit path FPU state tracking amdgpu HMM under vkd3d Proton/DXVK workloads on RDNA3 hardware Given the reproducibility and the clean hardware tests, this seems like it could be kernal related and not a hardware issue. I'm happy to try and provide any additiona dmesg/journalctl logging or proton logs or testing on any other kernels or debug kernels if needed/requested Please advise on next steps or additional diagnostics.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2136907 Title: [REGRESSION?] NULL deref in syscall_exit_to_user_mode and FPU state warning under Proton/DXVK/vkd3d on Z790 + RX 7900 XTX To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2136907/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
