The G5 ran fine for hours building stuff, but I got this at shutdown: [...] BUG: non-zero pgtables_bytes on freeing mm: -4096 systemd-shutdown[1]: Syncing filesystems and block devices. systemd-shutdown[1]: Powering off. ============================================================================= BUG pgtable-2^9 (Tainted: G T ): Object already free ----------------------------------------------------------------------------- Slab 0xc0003f0000074e00 objects=2 used=0 fp=0xc000000001d3c000 flags=0x10201(locked|slab|head|zone=0) Object 0xc000000001d3c000 @offset=16384 fp=0x0000000000000000 Redzone c000000001d3b000: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb ................ Redzone c000000001d3b010: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb ................ [...] Object c000000001d3c060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ Object c000000001d3c070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ [...] Padding c000000001d3d110: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ Padding c000000001d3d120: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ [...] Padding c000000001d3dfe0: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ Padding c000000001d3dff0: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ CPU: 0 PID: 0 Comm: swapper/0 Tainted: G T 6.0.9-gentoo-PMacG5 #1 Call Trace: [c00000000fffb880] [c00000000072b860] .dump_stack_lvl+0x7c/0xd8 (unreliable) [c00000000fffb910] [c0000000002ddb4c] .print_trailer+0x1c0/0x210 [c00000000fffb9b0] [c0000000002ddbe0] .object_err+0x44/0x84 [c00000000fffba40] [c0000000002d6614] .free_debug_processing+0x394/0x4d0 [c00000000fffbb20] [c0000000002d6a3c] .__slab_free+0x2ec/0x550 [c00000000fffbc40] [c000000000046dd0] .__tlb_remove_table+0x1c0/0x1e0 [c00000000fffbcc0] [c00000000028853c] .tlb_remove_table_rcu+0x4c/0xa0 [c00000000fffbd40] [c000000000122854] .rcu_core+0x684/0x1170 [c00000000fffbe70] [c000000000b3a8d4] .__do_softirq+0x164/0x338 [c00000000fffbf90] [c000000000011770] .do_softirq_own_stack+0x30/0x70 [c0000000013d3680] [c00000000008c5e8] .__irq_exit_rcu+0xf8/0x130 [c0000000013d3700] [c00000000008d330] .irq_exit+0x10/0x30 [c0000000013d3770] [c00000000001cce0] .timer_interrupt+0x210/0x3d0 [c0000000013d3810] [c0000000000088e8] decrementer_common_virt+0x208/0x210 --- interrupt: 900 at power4_idle_nap_return+0x0/0x4 NIP: c000000000033e3c LR: c000000000016ec4 CTR: c000000000016e40 REGS: c0000000013d3880 TRAP: 0900 Tainted: G T (6.0.9-gentoo-PMacG5) MSR: 9000000000009032 CR: 44000484 XER: 00000000 IRQMASK: 0 GPR00: c000000000016d30 c0000000013d3b20 c0000000013d7c00 0000000000000001 GPR04: 0000000000000000 0000000000000000 0000000000000000 9000000000049032 GPR08: 0000000000000001 c00000000139ae00 0000000000000000 0000000000000000 GPR12: 0000000000000000 c00000000146f000 0000000000000003 0000000000000000 GPR16: 0000000002050900 0000000002050c60 00000000020509c8 0000000002050ec0 GPR20: 00000000020d4de8 0000000002050ee8 0000000002807c00 0000000002807c00 GPR24: 0000000002807c00 0000000000080000 c0000000013e1ad8 0000000000000001 GPR28: c0000000013e1a48 c00000000139ae80 c00000000139ae00 c0000000013e1970 NIP [c000000000033e3c] power4_idle_nap_return+0x0/0x4 LR [c000000000016ec4] .power4_idle+0x84/0xd0 --- interrupt: 900 [c0000000013d3b20] [c00000000139ae00] 0xc00000000139ae00 (unreliable) [c0000000013d3ba0] [c000000000016d30] .arch_cpu_idle+0x60/0x170 [c0000000013d3c20] [c000000000b39e04] .default_idle_call+0x44/0x8c [c0000000013d3c90] [c0000000000e2b64] .do_idle+0x104/0x1e0 [c0000000013d3d40] [c0000000000e2e4c] .cpu_startup_entry+0x2c/0x40 [c0000000013d3dc0] [c00000000000fd98] .rest_init+0xd8/0xe0 [c0000000013d3e40] [c000000001004970] .arch_post_acpi_subsys_init+0x0/0x5c [c0000000013d3eb0] [c000000001005674] .start_kernel+0xadc/0xb68 [c0000000013d3f90] [c00000000000c6d8] start_here_common+0x1c/0x44 Disabling lock debugging due to kernel taint FIX pgtable-2^9: Object at 0xc000000001d3c000 not freed [...] Some data about the machine: # lspci 0000:00:0b.0 PCI bridge: Apple Inc. CPC945 PCIe Bridge 0000:0a:00.0 VGA compatible controller: NVIDIA Corporation NV43 [GeForce 6600 LE] (rev a2) 0001:00:00.0 Host bridge: Apple Inc. U4 HT Bridge 0001:00:01.0 PCI bridge: Broadcom BCM5780 [HT2000] PCI-X bridge (rev a3) 0001:00:02.0 PCI bridge: Broadcom BCM5780 [HT2000] PCI-X bridge (rev a3) 0001:00:03.0 PCI bridge: Broadcom BCM5780 [HT2000] PCI-Express Bridge (rev a3) 0001:00:04.0 PCI bridge: Broadcom BCM5780 [HT2000] PCI-Express Bridge (rev a3) 0001:00:05.0 PCI bridge: Broadcom BCM5780 [HT2000] PCI-Express Bridge (rev a3) 0001:00:06.0 PCI bridge: Broadcom BCM5780 [HT2000] PCI-Express Bridge (rev a3) 0001:00:07.0 PCI bridge: Apple Inc. Shasta PCI Bridge 0001:00:08.0 PCI bridge: Apple Inc. Shasta PCI Bridge 0001:00:09.0 PCI bridge: Apple Inc. Shasta PCI Bridge 0001:01:07.0 Unassigned class [ff00]: Apple Inc. Shasta Mac I/O 0001:01:0b.0 USB controller: NEC Corporation OHCI USB Controller (rev 43) 0001:01:0b.1 USB controller: NEC Corporation OHCI USB Controller (rev 43) 0001:01:0b.2 USB controller: NEC Corporation uPD72010x USB 2.0 Controller (rev 04) 0001:03:0c.0 IDE interface: Broadcom K2 SATA 0001:03:0d.0 Unassigned class [ff00]: Apple Inc. Shasta IDE 0001:03:0e.0 FireWire (IEEE 1394): Apple Inc. Shasta Firewire 0001:05:04.0 Ethernet controller: Broadcom Inc. and subsidiaries NetXtreme BCM5780 Gigabit Ethernet (rev 03) 0001:05:04.1 Ethernet controller: Broadcom Inc. and subsidiaries NetXtreme BCM5780 Gigabit Ethernet (rev 03) 0001:06:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] RV516 [Radeon X1300/X1550 Series] 0001:06:00.1 Display controller: Advanced Micro Devices, Inc. [AMD/ATI] RV516 [Radeon X1300/X1550 Series] (Secondary) 0001:08:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 06) 0001:09:00.0 Non-Volatile memory controller: Sandisk Corp WD Black SN750 / PC SN730 NVMe SSD # lscpu Architecture: ppc64 CPU op-mode(s): 32-bit, 64-bit Byte Order: Big Endian CPU(s): 2 On-line CPU(s) list: 0,1 Model name: PPC970MP, altivec supported Model: 1.1 (pvr 0044 0101) Thread(s) per core: 1 Core(s) per socket: 2 Socket(s): 1 CPU max MHz: 2300.0000 CPU min MHz: 1150.0000 Caches (sum of all): L1d: 64 KiB (2 instances) L1i: 128 KiB (2 instances) L2: 2 MiB (2 instances) This has been https://bugzilla.kernel.org/show_bug.cgi?id=216735 but I was suggested to better post issues like this here on the mailing list. Kernel dmesg and .config attached. Cheers, Erhard F.