Thanks. I completed the additional testing. ### Mainline 7.0.12
Ubuntu Mainline `7.0.12-070012-generic` booted successfully. The issue reproduced almost immediately: ```text uname -r 7.0.12-070012-generic ``` ```text Aug 24 15:12:09 z-390 kernel: rcu_tasks_wait_gp: rcu_tasks grace period number 1 (since boot) is 10104 jiffies old. Aug 24 15:12:21 z-390 kernel: rcu_tasks_wait_gp: rcu_tasks grace period number 5 (since boot) is 10119 jiffies old. ``` I attached: ```text journal-mainline-7.0.12.txt ``` to this bug. ### Mainline 7.2 I was not able to complete a clean 7.2 test because the installed NVIDIA driver does not currently build against the 7.2 mainline kernel. I first tested with the existing NVIDIA `580.173.02` driver. Its DKMS build fails against 7.2 because Linux 7.2 no longer provides the kernel `strncpy()` API. I also tested the newer Ubuntu NVIDIA `595.84` package. It builds successfully against Mainline 7.0.12 when using GCC 14, but its 7.2 DKMS build fails for the same reason: ```text nvidia/os-interface.c:732:5: error: implicit declaration of function ‘strncpy’ ``` I therefore stopped the 7.2 test rather than continue modifying the NVIDIA source, since doing so would make the resulting kernel comparison less controlled. ### Reconfirmation after restoring the original setup I restored NVIDIA `580.173.02` and the normal DisplayLink/evdi setup. On Ubuntu HWE `7.0.0-30-generic`, with both NVIDIA and evdi loaded, the issue immediately reproduced again: ```text Aug 24 16:42:02 z-390 kernel: rcu_tasks_wait_gp: rcu_tasks grace period number 1 (since boot) is 10088 jiffies old. Aug 24 16:42:12 z-390 kernel: rcu_tasks_wait_gp: rcu_tasks grace period number 5 (since boot) is 10120 jiffies old. Aug 24 16:43:11 z-390 kernel: rcu_tasks_wait_gp: rcu_tasks grace period number 17 (since boot) is 10088 jiffies old. Aug 24 16:43:23 z-390 kernel: rcu_tasks_wait_gp: rcu_tasks grace period number 21 (since boot) is 10088 jiffies old. ``` Loaded graphics modules included: ```text nvidia_uvm nvidia_drm nvidia_modeset nvidia evdi ``` I then returned to the known-good kernel: ```text 6.17.0-40-generic ``` under the restored NVIDIA 580 / evdi configuration. Current result: ```text journalctl -k -b 0 --no-pager | grep -c "rcu_tasks_wait_gp" 0 ``` So the current comparison is: * `6.17.0-40-generic` → **0 stalls** * `7.0.0-29/30-generic` → **stalls reproducibly** * `7.0.0-30-generic` with evdi disabled → **stalls** * Mainline `7.0.12-070012-generic` → **stalls** * Mainline 7.2 → unable to test cleanly because current NVIDIA 580 and 595 DKMS sources do not build against Linux 7.2 Please let me know if you would like me to test another kernel version or another specific configuration. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2164624 Title: rcu_tasks_wait_gp stalls on 7.0.0-28/29-generic (HWE noble), absent on 6.17.0-40-generic To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2164624/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
