Update – 2026-10-04: issue now reproduced on 7.0.0-31-generic Additional testing has confirmed that this issue is not limited to 7.0.0-34-generic. The system is currently running: 7.0.0-31-generic #31-Ubuntu SMP PREEMPT_DYNAMIC Multiple kernel panics occurred on 7.0.0-31-generic on October 4. Kdump successfully captured the crashes. The repeated failure signature includes: BUG: kernel NULL pointer dereference, address: 0000000000000100 RIP: iov_iter_advance+0x1c6/0x290 with the call trace involving: cifs_prepare_write [cifs] followed by: Kernel panic - not syncing: Fatal exception Another captured crash occurred in: netfs_limit_iter [netfs] This is significant because 7.0.0-31-generic had previously appeared stable compared with 7.0.0-34-generic. It can no longer be considered an unaffected rollback kernel. Full kdump evidence was captured for the new crashes. Ubuntu 7.0.0-38.38 is currently available from resolute-updates, but I have not tested or booted that kernel yet because I have not established whether it contains a fix for this CIFS/netfs failure. I can provide additional vmcore/dmesg captures if useful.
** Attachment added: "bug-2169171-kdump-dmesg-2026-10-04-kernel-31.txt" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2169171/+attachment/6005738/+files/bug-2169171-kdump-dmesg-2026-10-04-kernel-31.txt -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2169171 Title: 7.0.0-34-generic: repeated NULL pointer dereference in iov_iter_advance during CIFS/netfs writes on Hyper-V To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2169171/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
