The kernel blows up when offlining a CPU: [ 82.891707] BUG: kernel NULL pointer dereference, address: 0000000000000000 [ 82.891959] #PF: supervisor read access in kernel mode [ 82.891959] #PF: error_code(0x0000) - not-present page [ 82.891959] PGD 0 P4D 0 [ 82.891959] Oops: 0000 [#1] PREEMPT SMP NOPTI [ 82.891959] CPU: 0 PID: 593 Comm: kworker/0:2 Not tainted 6.8.0-80-generic #80-Ubuntu [ 82.891959] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 82.891959] Workqueue: events work_for_cpu_fn [ 82.891959] RIP: 0010:memcg_hotplug_cpu_dead+0x65/0xc0 [ 82.891959] Code: 44 00 00 48 89 df e8 5a ef ff ff 48 89 c3 41 f7 c5 00 02 00 00 74 06 fb 0f 1f 44 00 00 4c 89 e7 e8 f0 cd ff ff e8 6b d9 d0 ff <48> 8b 03 a8 03 75 1e 65 48 ff 08 e8 ab 35 d1 ff 31 c0 5b 41 5c 41 [ 82.891959] RSP: 0018:ffffbd548170bd10 EFLAGS: 00000246 [ 82.891959] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 82.891959] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 [ 82.891959] RBP: ffffbd548170bd28 R08: 0000000000000000 R09: 0000000000000000 [ 82.891959] R10: 000000000000001c R11: 0000000000000000 R12: ffff99183bcb0c00 [ 82.891959] R13: 0000000000000286 R14: 0000000000000001 R15: 0000000000000000 [ 82.891959] FS: 0000000000000000(0000) GS:ffff99183bc00000(0000) knlGS:0000000000000000 [ 82.891959] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 82.891959] CR2: 0000000000000000 CR3: 000000001c43c000 CR4: 00000000000006f0 [ 82.891959] Call Trace: [ 82.891959] <TASK> [ 82.891959] ? show_regs+0x6d/0x80 [ 82.891959] ? __die+0x24/0x80 [ 82.891959] ? page_fault_oops+0x99/0x1b0 [ 82.891959] ? kernelmode_fixup_or_oops.isra.0+0x69/0x90 [ 82.891959] ? __bad_area_nosemaphore+0x19e/0x2c0 [ 82.891959] ? bad_area_nosemaphore+0x16/0x30 [ 82.891959] ? do_user_addr_fault+0x29d/0x670 [ 82.891959] ? exc_page_fault+0x83/0x1b0 [ 82.891959] ? asm_exc_page_fault+0x27/0x30 [ 82.891959] ? memcg_hotplug_cpu_dead+0x65/0xc0 [ 82.891959] ? __pfx_memcg_hotplug_cpu_dead+0x10/0x10 [ 82.891959] cpuhp_invoke_callback+0x348/0x530 [ 82.891959] __cpuhp_invoke_callback_range+0x80/0x100 [ 82.891959] _cpu_down+0xfb/0x280 [ 82.891959] __cpu_down_maps_locked+0x15/0x30 [ 82.891959] work_for_cpu_fn+0x1a/0x30 [ 82.891959] process_one_work+0x184/0x3a0 [ 82.891959] worker_thread+0x306/0x440 [ 82.891959] ? _raw_spin_lock_irqsave+0xe/0x20 [ 82.891959] ? __pfx_worker_thread+0x10/0x10 [ 82.891959] kthread+0xf2/0x120 [ 82.891959] ? __pfx_kthread+0x10/0x10 [ 82.891959] ret_from_fork+0x47/0x70 [ 82.891959] ? __pfx_kthread+0x10/0x10 [ 82.891959] ret_from_fork_asm+0x1b/0x30 [ 82.891959] </TASK> [ 82.891959] Modules linked in: kvm_amd ccp kvm irqbypass input_leds psmouse ahci libahci serio_raw overlay 9pnet_virtio virtiofs 9p 9pnet netfs [ 82.891959] CR2: 0000000000000000 [ 82.891959] ---[ end trace 0000000000000000 ]--- [ 82.891959] RIP: 0010:memcg_hotplug_cpu_dead+0x65/0xc0 [ 82.891959] Code: 44 00 00 48 89 df e8 5a ef ff ff 48 89 c3 41 f7 c5 00 02 00 00 74 06 fb 0f 1f 44 00 00 4c 89 e7 e8 f0 cd ff ff e8 6b d9 d0 ff <48> 8b 03 a8 03 75 1e 65 48 ff 08 e8 ab 35 d1 ff 31 c0 5b 41 5c 41 [ 82.891959] RSP: 0018:ffffbd548170bd10 EFLAGS: 00000246 [ 82.891959] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 82.891959] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 [ 82.891959] RBP: ffffbd548170bd28 R08: 0000000000000000 R09: 0000000000000000 [ 82.891959] R10: 000000000000001c R11: 0000000000000000 R12: ffff99183bcb0c00 [ 82.891959] R13: 0000000000000286 R14: 0000000000000001 R15: 0000000000000000 [ 82.891959] FS: 0000000000000000(0000) GS:ffff99183bc00000(0000) knlGS:0000000000000000 [ 82.891959] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 82.891959] CR2: 0000000000000000 CR3: 000000001c43c000 CR4: 00000000000006f0 [ 82.891959] note: kworker/0:2[593] exited with irqs disabled
The fix is to backport [1] which adds a NULL check to obj_cgroup_put(). [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=91b71e78b8e4 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2121673 Title: noble ubuntu_ftrace_smoke_test:mmiotrace timeout on aws:r5.metal To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2121673/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
