Bug 216368

Summary: do_IRQ: stack overflow at boot during btrfs handling on a PowerMac G5 11,2
Product: Platform Specific/Hardware Reporter: Erhard F. (erhard_f)
Component: PPC-64Assignee: platform_ppc-64
Status: RESOLVED OBSOLETE    
Severity: normal CC: christophe.leroy, dsterba, regressions
Priority: P1    
Hardware: PPC-64   
OS: Linux   
Kernel Version: 6.0-rc1 Subsystem:
Regression: No Bisected commit-id:
Attachments: dmesg (kernel 6.0-rc1, PowerMac G5 11,2)
dmesg (kernel 6.0-rc1, PowerMac G5 11,2), 2nd time
kernel .config (kernel 6.0-rc1, PowerMac G5 11,2)
dmesg (6.1.0, PowerMac G5 11,2)
kernel .config (6.1.0, PowerMac G5 11,2)

Description Erhard F. 2022-08-16 00:09:48 UTC
Created attachment 301578 [details]
dmesg (kernel 6.0-rc1, PowerMac G5 11,2)

Happens sometimes at boot on my G5 on v6.0-rc1:

[...]
do_IRQ: stack overflow: 3072
CPU: 0 PID: 294 Comm: Xvnc Tainted: G                T  6.0.0-rc1-PMacG5 #1
Call Trace:
[c00000000fff7e80] [c0000000006d0200] .dump_stack_lvl+0x7c/0xc4 (unreliable)
[c00000000fff7f10] [c0000000000107f4] .__do_irq+0x114/0x120
[c00000000fff7f90] [c0000000000111a8] .__do_IRQ+0x78/0xd0
[c000000019da4c00] [0000000003684000] 0x3684000
[c000000019da4c90] [c0000000000112c4] .do_IRQ+0xc4/0x1d0
[c000000019da4d10] [c000000000008018] hardware_interrupt_common_virt+0x208/0x210
--- interrupt: 500 at .ppc_iommu_map_sg+0x220/0x520
NIP:  c000000000034200 LR: c0000000000341e0 CTR: 0000000000000000
REGS: c000000019da4d80 TRAP: 0500   Tainted: G                T   (6.0.0-rc1-PMacG5)
MSR:  900000000200b032 <SF,HV,VEC,EE,FP,ME,IR,DR,RI>  CR: 24224242  XER: 20000000
IRQMASK: 0 
GPR00: c0000000000341e0 c000000019da5020 c0000000013df100 0000000000000000 
GPR04: 0000000000000000 0000000000000001 0000000000000001 0000000000000000 
GPR08: 0000000000000000 0000000000000000 c0000000193c6200 c000000000cb1168 
GPR12: 0000000044224242 c0000000014ae000 c000000020249000 0000000000000001 
GPR16: 0000000000000001 c000000020249000 ffffffffffffffff 0000000000000100 
GPR20: 0000000000000002 c00000000190c0d0 0000000000000001 0000000003684000 
GPR24: 0000000000001000 c000000020249000 000000000000000c 0000000000000001 
GPR28: 0000000000001000 c000000001435500 0000000003684000 c000000020249020 
NIP [c000000000034200] .ppc_iommu_map_sg+0x220/0x520
LR [c0000000000341e0] .ppc_iommu_map_sg+0x200/0x520
--- interrupt: 500
[c000000019da5140] [c00000000003316c] .dma_iommu_map_sg+0x4c/0x60
[c000000019da51b0] [c000000000123f68] .__dma_map_sg_attrs+0x108/0x1a0
[c000000019da5240] [c00000000012405c] .dma_map_sgtable+0x2c/0x60
[c000000019da52c0] [c0000000007ffeb4] .nvme_prep_rq.part.0+0xe4/0xc70
[c000000019da53c0] [c000000000800acc] .nvme_queue_rq+0x8c/0x2d0
[c000000019da5470] [c0000000005dc600] .blk_mq_dispatch_rq_list+0x250/0xb30
[c000000019da55b0] [c0000000005e5070] .blk_mq_do_dispatch_sched+0x430/0x4d0
[c000000019da56d0] [c0000000005e5520] .__blk_mq_sched_dispatch_requests+0x150/0x1d0
[c000000019da5780] [c0000000005e5630] .blk_mq_sched_dispatch_requests+0x40/0x90
[c000000019da5800] [c0000000005d94a8] .__blk_mq_run_hw_queue+0xc8/0x100
[c000000019da5880] [c0000000005e5a98] .blk_mq_sched_insert_requests+0xb8/0x290
[c000000019da5930] [c0000000005dd594] .blk_mq_flush_plug_list+0x1d4/0x3b0
[c000000019da5a10] [c0000000005dd858] .blk_add_rq_to_plug+0xe8/0x160
[c000000019da5a90] [c0000000005dde00] .blk_mq_submit_bio+0x270/0x650
[c000000019da5b90] [c0000000005ca0c4] .__submit_bio+0x174/0x2d0
[c000000019da5c30] [c0000000005ca940] .submit_bio_noacct_nocheck+0x2b0/0x330
[c000000019da5cf0] [c0000000004d66b4] .btrfs_submit_bio+0x274/0x5c0
[c000000019da5e00] [c000000000481f44] .btrfs_submit_metadata_bio+0x54/0x110
[c000000019da5e80] [c0000000004bd828] .submit_one_bio+0xb8/0x130
[c000000019da5f00] [c0000000004c84b0] .read_extent_buffer_pages+0x310/0x750
[c000000019da6020] [c000000000481b48] .btrfs_read_extent_buffer+0xd8/0x1b0
[c000000019da60f0] [c00000000048208c] .read_tree_block+0x5c/0x130
[c000000019da6190] [c0000000004609a8] .read_block_for_search+0x2c8/0x410
[c000000019da62b0] [c000000000466a30] .btrfs_search_slot+0x380/0xcf0
[c000000019da6400] [c00000000047adf4] .btrfs_lookup_csum+0x64/0x1d0
[c000000019da64d0] [c00000000047b754] .btrfs_lookup_bio_sums+0x274/0x6e0
[c000000019da6630] [c000000000505d18] .btrfs_submit_compressed_read+0x3b8/0x520
[c000000019da6720] [c0000000004954b4] .btrfs_submit_data_read_bio+0xc4/0xe0
[c000000019da67b0] [c0000000004bd7fc] .submit_one_bio+0x8c/0x130
[c000000019da6830] [c0000000004c4478] .submit_extent_page+0x548/0x590
[c000000019da6980] [c0000000004c4f80] .btrfs_do_readpage+0x330/0x970
[c000000019da6ad0] [c0000000004c67f4] .extent_readahead+0x2b4/0x430
[c000000019da6c70] [c000000000490440] .btrfs_readahead+0x10/0x30
[c000000019da6ce0] [c0000000002219bc] .read_pages+0x8c/0x360
[c000000019da6db0] [c000000000221e0c] .page_cache_ra_unbounded+0x17c/0x230
[c000000019da6e90] [c000000000214cb0] .filemap_fault+0x630/0xa90
[c000000019da6fa0] [c000000000258078] .__do_fault+0x58/0x110
[c000000019da7020] [c00000000025f030] .__handle_mm_fault+0xe40/0x14e0
[c000000019da7180] [c00000000025f7e0] .handle_mm_fault+0x110/0x330
[c000000019da7230] [c00000000003dd20] .___do_page_fault+0x1c0/0x950
[c000000019da72e0] [c00000000003e590] .hash__do_page_fault+0x20/0xb0
[c000000019da7360] [c000000000044a38] .do_hash_fault+0x248/0x300
[c000000019da73e0] [c000000000007894] data_access_common_virt+0x194/0x1f0
--- interrupt: 300 at .__arch_clear_user+0x20/0x150
NIP:  c0000000000517d0 LR: c0000000003893bc CTR: 0000000000000000
REGS: c000000019da7450 TRAP: 0300   Tainted: G                T   (6.0.0-rc1-PMacG5)
MSR:  900000000200b032 <SF,HV,VEC,EE,FP,ME,IR,DR,RI>  CR: 4402444b  XER: 20000000
DAR: 000000011236a5b5 DSISR: 42000000 IRQMASK: 0 
GPR00: 0000000000000000 c000000019da76f0 c0000000013df100 000000011236a5b5 
GPR04: 0000000000000a4b c000000000cd7178 0000000000000003 0000000000000000 
GPR08: 000000011236a5b5 0000000000000000 00003ffffffff000 00000000000000e8 
GPR12: 0000000024024440 c0000000014ae000 c000000019a7bfc0 0000000000000008 
GPR16: 00000000fffff000 000000011236a5b5 00000000003c7470 c000000019a7fa00 
GPR20: 000000011233e498 c000000019f42940 0000000000000000 c000000019a7be00 
GPR24: 000000000038a5b5 0000000111fe0000 c000000019a7c400 0000000112326867 
GPR28: 0000000111fe0000 000000000035ac30 0000000111fe0040 c0000000013e89f0 
NIP [c0000000000517d0] .__arch_clear_user+0x20/0x150
LR [c0000000003893bc] .padzero+0x6c/0x140
--- interrupt: 300
[c000000019da76f0] [c000000000388244] .set_brk+0x64/0x90 (unreliable)
[c000000019da7770] [c000000000389edc] .load_elf_binary+0x8dc/0x1c00
[c000000019da78c0] [c000000000308ee8] .bprm_execve+0x298/0x6f0
[c000000019da79a0] [c000000000309520] .do_execveat_common.isra.0+0x1e0/0x310
[c000000019da7a70] [c00000000030a7ac] .__se_sys_execve+0x3c/0x50
[c000000019da7ae0] [c000000000022660] .system_call_exception+0x160/0x290
[c000000019da7e10] [c00000000000b33c] system_call_common+0xec/0x250
--- interrupt: c00 at 0x3fff904d8ccc
NIP:  00003fff904d8ccc LR: 00003fff904d9668 CTR: 0000000000000000
REGS: c000000019da7e80 TRAP: 0c00   Tainted: G                T   (6.0.0-rc1-PMacG5)
MSR:  900000000200f032 <SF,HV,VEC,EE,PR,FP,ME,IR,DR,RI>  CR: 22002220  XER: 00000000
IRQMASK: 0 
GPR00: 000000000000000b 00003fffff2f01f0 00003fff90617200 00003fffff2f1cb8 
GPR04: 000000013bac0b00 00003fffff2f0cd8 fefefefefefefeff 7f7f7f7f7f7f7f7f 
GPR08: 00003fffff2f1cb8 0000000000000000 0000000000000000 0000000000000000 
GPR12: 0000000000000000 00003fff90806860 00000001301c8c50 000000010dd637b0 
GPR16: 0000000129bcedc8 000000013edfaac0 0000000000000000 00003ffff0a28d60 
GPR20: 000000000000002f 0000000000000000 00003fffb2027c70 00003fff90861000 
GPR24: 000000013babfee8 000000013bac0b00 000000013bac0b00 00003fffff2f0cd8 
GPR28: 0000000000000001 000000013babfae0 00003fffff2f1cb8 0000000000000000 
NIP [00003fff904d8ccc] 0x3fff904d8ccc
LR [00003fff904d9668] 0x3fff904d9668


The machine stays usable though.

Some data about the machine:
 # inxi -bZ
System:
  Host: T800 Kernel: 6.0.0-rc1-PMacG5 arch: ppc64 bits: 64 Console: pty pts/0
    Distro: Gentoo Base System release 2.8
Machine:
  Type: PPC System: PowerMac11 2 details: N/A
    mobo: PowerMac11,2 MacRISC4 Power Macintosh  serial: R6V
CPU:
  Info: dual core PPC970MP altivec supported [MCP] speed (MHz): avg: 1150
    min/max: 1150/2300
Graphics:
  Device-1: NVIDIA NV43 [GeForce 6600 LE] driver: nouveau v: kernel
  Device-2: AMD RV516 [Radeon X1300/X1550 Series] driver: N/A
  Display: x11 server: X.Org v: 21.1.1 driver: X: loaded: nouveau
    unloaded: fbdev,modesetting gpu: nouveau resolution: 1400x900~60Hz
  OpenGL: renderer: llvmpipe (LLVM 14.0.6 128 bits) v: 4.5 Mesa 22.0.5
Network:
  Device-1: Broadcom NetXtreme BCM5780 Gigabit Ethernet driver: tg3
  Device-2: Broadcom NetXtreme BCM5780 Gigabit Ethernet driver: tg3
  Device-3: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet
    driver: r8169

 # 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
Comment 1 Erhard F. 2022-08-16 00:10:22 UTC
Created attachment 301579 [details]
dmesg (kernel 6.0-rc1, PowerMac G5 11,2), 2nd time
Comment 2 Erhard F. 2022-08-16 00:10:46 UTC
Created attachment 301580 [details]
kernel .config (kernel 6.0-rc1, PowerMac G5 11,2)
Comment 3 Christophe Leroy 2022-08-16 07:30:08 UTC
That might be a consequence of commit 41f20d6db2b6 ("powerpc/irq: Increase stack_overflow detection limit when KASAN is enabled") which increased the limit from 2k to 4k for PPC64.

This happens when you get an IRQ while being deep into BTRFS handling it seems.

It should be investigated with BTRFS team why the callstack is so deep.
Comment 4 The Linux kernel's regression tracker (Thorsten Leemhuis) 2022-08-25 11:06:43 UTC
(In reply to Christophe Leroy from comment #3)

> It should be investigated with BTRFS team why the callstack is so deep.

Did anyone forward this to the Btrfs team? if so: where? If not I guess I can do that.
Comment 5 Erhard F. 2022-08-25 11:57:14 UTC
(In reply to The Linux kernel's regression tracker (Thorsten Leemhuis) from comment #4)
> Did anyone forward this to the Btrfs team? if so: where? If not I guess I
> can do that.
I added David Sterba (dsterba@suse.com) to the CC list, who is a maintainer. Don't know whether that's enough.
Comment 6 David Sterba 2022-09-05 17:16:28 UTC
(In reply to Christophe Leroy from comment #3)
> This happens when you get an IRQ while being deep into BTRFS handling it
> seems.
> 
> It should be investigated with BTRFS team why the callstack is so deep.

There's nothing strange on the call stack, contains all functions that are expected when handling a page fault, looking up internal structures and then passing to block layer to get the bytes from the device.

Deep stack, measured by number of functions and also size is normal for filesystrems and we try to keep the size sane, so far we haven't seen such problems on x86_64, the overall stack size is 16K an on debug kernel there are about 6K consumed at maximum (reported by CONFIG_DEBUG_STACK_USAGE=y and CONFIG_SCHED_STACK_END_CHECK=y), the lowest value found I see in my logs is 10576.

That is on a simple IO stack, ie. what's below the filesystem, as you can see the mblk-mq, NVMe and DMA also cut some stack space, but this also does not seem suspicious. What could be significant is layering with MD, device mapper, NFS, networking.

The first number in the stack trace is the stack pointer, calculating what btrfs itself takes:

[c000000019da5cf0] [c0000000004d66b4] .btrfs_submit_bio+0x274/0x5c0
[c000000019da5e00] [c000000000481f44] .btrfs_submit_metadata_bio+0x54/0x110
[c000000019da5e80] [c0000000004bd828] .submit_one_bio+0xb8/0x130
[c000000019da5f00] [c0000000004c84b0] .read_extent_buffer_pages+0x310/0x750
[c000000019da6020] [c000000000481b48] .btrfs_read_extent_buffer+0xd8/0x1b0
[c000000019da60f0] [c00000000048208c] .read_tree_block+0x5c/0x130
[c000000019da6190] [c0000000004609a8] .read_block_for_search+0x2c8/0x410
[c000000019da62b0] [c000000000466a30] .btrfs_search_slot+0x380/0xcf0
[c000000019da6400] [c00000000047adf4] .btrfs_lookup_csum+0x64/0x1d0
[c000000019da64d0] [c00000000047b754] .btrfs_lookup_bio_sums+0x274/0x6e0
[c000000019da6630] [c000000000505d18] .btrfs_submit_compressed_read+0x3b8/0x520
[c000000019da6720] [c0000000004954b4] .btrfs_submit_data_read_bio+0xc4/0xe0
[c000000019da67b0] [c0000000004bd7fc] .submit_one_bio+0x8c/0x130
[c000000019da6830] [c0000000004c4478] .submit_extent_page+0x548/0x590
[c000000019da6980] [c0000000004c4f80] .btrfs_do_readpage+0x330/0x970
[c000000019da6ad0] [c0000000004c67f4] .extent_readahead+0x2b4/0x430
[c000000019da6c70] [c000000000490440] .btrfs_readahead+0x10/0x30

0xc000000019da6c70 - 0xc000000019da5cf0 = 3968

That's on par with my expectation.

Total stack space is (from syscall to the irq handler):

0xc000000019da7e10 - 0xc000000019da4c00 = 12816

That's getting close to 16K but still a few kilobytes before overflow, the IRQ has it's own stack (that needs to be set up from the kthread/process context).

As you mention KASAN, that can add some stack consumption due to padding and alignment, but so far I don't know what exactly is the warning measuring. Calculating back from do_IRQ by 3072 it's roughly 0xc000000019da5910, inside blk_mq_flush_plug_list.

I remember some build reports from PPC that due to a different compiler used the function inlining caused increased stack space consumption (eg. due to aggressive optimizations that unrolled loops too much using several additional temporary variables). So that should be investigated too before blaming btrfs.
Comment 7 Erhard F. 2022-12-18 23:19:52 UTC
Created attachment 303424 [details]
dmesg (6.1.0, PowerMac G5 11,2)

Still in v6.1.0. Happens sometimes at boot on my G5:

[...]
Stack Depot allocating hash table of 1048576 entries with kvcalloc
nouveau 0000:0a:00.0: DRM: Setting dpms mode 3 on TV encoder (output 4)
do_IRQ: stack overflow: 3440
CPU: 0 PID: 264 Comm: NetworkManager Tainted: G                T  6.1.0-gentoo-PMacG5 #2
Hardware name: PowerMac11,2 PPC970MP 0x440101 PowerMac
Call Trace:
[c00000000fff7e80] [c000000000b24980] .dump_stack_lvl+0x7c/0xd8 (unreliable)
[c00000000fff7f10] [c000000000010db4] .__do_irq+0x124/0x130
[c00000000fff7f90] [c0000000000114f8] .__do_IRQ+0x78/0x130
[c000000015c5cd70] [0000000000000001] 0x1
[c000000015c5ce00] [c0000000000116b4] .do_IRQ+0x104/0x250
[c000000015c5ce80] [c000000000008034] hardware_interrupt_common_virt+0x214/0x220
--- interrupt: 500 at .dart_cache_sync+0x0/0x100
NIP:  c000000000063860 LR: c000000000063ce4 CTR: 0000000000000000
REGS: c000000015c5cef0 TRAP: 0500   Tainted: G                T   (6.1.0-gentoo-PMacG5)
MSR:  900000000200b032 <SF,HV,VEC,EE,FP,ME,IR,DR,RI>  CR: 44224280  XER: 20000000
IRQMASK: 0 
GPR00: c000000000036620 c000000015c5d190 c000000000d9d500 c00000007f00962c 
GPR04: 0000000000000001 0000000000000001 c000000018e2e000 0000000000000002 
GPR08: c00000007f00962c 0000000080018e2d c00000007f009630 000000000258b000 
GPR12: 0000000000001000 c0000000014ba000 0000000000000001 0000000000000001 
GPR16: 0000000000000001 c0000000177f4000 0000000000000001 ffffffffffffffff 
GPR20: c0000000177f4080 0000000000000002 c0000000018cc0d0 000000000258b000 
GPR24: 0000000000001000 c0000000177f4000 0000000000000008 0000000000000004 
GPR28: 0000000000000001 0000000000000001 0000000000000001 000000000000258b 
NIP [c000000000063860] .dart_cache_sync+0x0/0x100
LR [c000000000063ce4] .dart_build+0x74/0x2b0
--- interrupt: 500
[c000000015c5d190] [0000000000000001] 0x1 (unreliable)
[c000000015c5d230] [c000000000036620] .ppc_iommu_map_sg+0x1f0/0x540
[c000000015c5d350] [c0000000000352bc] .dma_iommu_map_sg+0x4c/0x90
[c000000015c5d3c0] [c000000000128098] .__dma_map_sg_attrs+0x168/0x1e0
[c000000015c5d450] [c000000000128188] .dma_map_sgtable+0x28/0x70
[c000000015c5d4d0] [c000000000869588] .nvme_prep_rq.part.0+0xd8/0xc00
[c000000015c5d5d0] [c00000000086a134] .nvme_queue_rq+0x84/0x2a0
[c000000015c5d670] [c00000000063d450] .blk_mq_dispatch_rq_list+0x260/0xb30
[c000000015c5d7b0] [c0000000006463a0] .blk_mq_do_dispatch_sched+0x3f0/0x4a0
[c000000015c5d8d0] [c000000000646860] .__blk_mq_sched_dispatch_requests+0x170/0x210
[c000000015c5d970] [c0000000006469bc] .blk_mq_sched_dispatch_requests+0x5c/0xc0
[c000000015c5d9f0] [c000000000639f48] .__blk_mq_run_hw_queue+0xd8/0x130
[c000000015c5da70] [c000000000646ed8] .blk_mq_sched_insert_requests+0xb8/0x2b0
[c000000015c5db20] [c00000000063e294] .blk_mq_flush_plug_list+0x1e4/0x3a0
[c000000015c5dbf0] [c00000000063e580] .blk_add_rq_to_plug+0x130/0x140
[c000000015c5dc70] [c00000000063eb2c] .blk_mq_submit_bio+0x23c/0x680
[c000000015c5dd60] [c000000000628b44] .__submit_bio+0x1b4/0x330
[c000000015c5de00] [c000000000629490] .submit_bio_noacct_nocheck+0x300/0x390
[c000000015c5deb0] [c0000000005129c4] .btrfs_submit_dev_bio+0xa4/0x190
[c000000015c5df30] [c00000000051e034] .btrfs_submit_bio+0x444/0x4c0
[c000000015c5e000] [c0000000004c5840] .btrfs_submit_metadata_bio+0x60/0x200
[c000000015c5e090] [c0000000005068f8] .submit_one_bio+0xf8/0x1b0
[c000000015c5e110] [c00000000050e5c4] .read_extent_buffer_pages+0x434/0x860
[c000000015c5e220] [c0000000004c5418] .btrfs_read_extent_buffer+0xd8/0x1d0
[c000000015c5e2f0] [c0000000004c5a7c] .read_tree_block+0x5c/0x190
[c000000015c5e390] [c0000000004a1654] .read_block_for_search+0x324/0x460
[c000000015c5e4a0] [c0000000004a8758] .btrfs_search_slot+0x568/0xe30
[c000000015c5e5e0] [c0000000004be004] .btrfs_lookup_csum+0x74/0x250
[c000000015c5e6c0] [c0000000004bea7c] .btrfs_lookup_bio_sums+0x27c/0x700
[c000000015c5e820] [c000000000550708] .btrfs_submit_compressed_read+0x448/0x610
[c000000015c5e920] [c0000000004da884] .btrfs_submit_data_read_bio+0x114/0x150
[c000000015c5e9b0] [c0000000005068a4] .submit_one_bio+0xa4/0x1b0
[c000000015c5ea30] [c000000000506eb8] .submit_extent_page+0x508/0x530
[c000000015c5eb80] [c00000000050a960] .btrfs_do_readpage+0x2d0/0x850
[c000000015c5ecb0] [c00000000050c2a4] .extent_readahead+0x2b4/0x450
[c000000015c5ee40] [c0000000004d4e90] .btrfs_readahead+0x10/0x30
[c000000015c5eeb0] [c00000000023eb44] .read_pages+0xa4/0x390
[c000000015c5ef80] [c00000000023efcc] .page_cache_ra_unbounded+0x19c/0x270
[c000000015c5f060] [c0000000002315b4] .filemap_fault+0x584/0xa10
[c000000015c5f180] [c00000000027f248] .__do_fault+0x58/0x120
[c000000015c5f200] [c000000000285e48] .__handle_mm_fault+0xbc8/0x10f0
[c000000015c5f350] [c000000000286490] .handle_mm_fault+0x120/0x3c0
[c000000015c5f400] [c000000000040af8] .___do_page_fault+0x218/0xa00
[c000000015c5f4b0] [c0000000000413f0] .hash__do_page_fault+0x20/0xf0
[c000000015c5f530] [c000000000048608] .do_hash_fault+0x2b8/0x3c0
[c000000015c5f5b0] [c0000000000078a8] data_access_common_virt+0x198/0x1f0
--- interrupt: 300 at .__arch_clear_user+0x5c/0x160
NIP:  c00000000005590c LR: c0000000003bbcac CTR: 000000000000000d
REGS: c000000015c5f620 TRAP: 0300   Tainted: G                T   (6.1.0-gentoo-PMacG5)
MSR:  900000000200b032 <SF,HV,VEC,EE,FP,ME,IR,DR,RI>  CR: 48428828  XER: 20000000
DAR: 000000013e036e48 DSISR: 42000000 IRQMASK: 0 
GPR00: 0000000000000000 c000000015c5f8c0 c000000000d9d500 000000013e036e48 
GPR04: 00000000000001b8 0000000000000000 000000000000000d 0000000000000000 
GPR08: 000000013e036e48 0000000000000000 00003ffffffff000 0000000000000000 
GPR12: 0000000000000000 c0000000014ba000 0000400000000000 c000000013f6f5f8 
GPR16: 0000000000000009 0000000000000000 00000000004b0990 00000000004c4328 
GPR20: 00000000004fa688 00000000004f6e48 c000000013f68800 c000000015c46c80 
GPR24: 0000000000000000 000000013e036e48 000000013db40000 c000000017830340 
GPR28: c000000013895680 0000000000000000 c000000013f6f400 c0000000013da970 
NIP [c00000000005590c] .__arch_clear_user+0x5c/0x160
LR [c0000000003bbcac] .padzero+0x7c/0x170
--- interrupt: 300
[c000000015c5f8c0] [c0000000003baa84] .set_brk+0x74/0xb0 (unreliable)
[c000000015c5f940] [c0000000003bc7f4] .load_elf_binary+0x854/0x1c40
[c000000015c5faa0] [c00000000032fffc] .bprm_execve+0x29c/0x730
[c000000015c5fb80] [c000000000330670] .do_execveat_common.isra.0+0x1e0/0x330
[c000000015c5fc50] [c000000000331904] .__se_sys_execve+0x44/0x80
[c000000015c5fcd0] [c000000000023e28] .system_call_exception+0x128/0x250
[c000000015c5fe10] [c00000000000b4d4] system_call_common+0xf4/0x258
--- interrupt: c00 at 0x3fff890b8e8c
NIP:  00003fff890b8e8c LR: 00003fff89323150 CTR: 0000000000000000
REGS: c000000015c5fe80 TRAP: 0c00   Tainted: G                T   (6.1.0-gentoo-PMacG5)
MSR:  900000000200f032 <SF,HV,VEC,EE,PR,FP,ME,IR,DR,RI>  CR: 2842448b  XER: 00000000
IRQMASK: 0 
GPR00: 000000000000000b 00003fffdb20b2c0 00003fff891f7200 000000014a4bc6f0 
GPR04: 000000014a4a1610 000000014a4535c0 000000014a4535c0 000000000000006e 
GPR08: fffffffeb5c1bb40 0000000000000000 0000000000000000 0000000000000000 
GPR12: 0000000000000000 00003fff898ad780 0000000000000000 0000000000000000 
GPR16: 0000000000000000 0000000000000000 00003fffdb20b5c0 000000014a4a0af0 
GPR20: 0000000000000000 0000000000000000 0000000000000001 0000000000000000 
GPR24: 0000000000000000 0000000000000000 00003fffdb20b938 000000014a3e3a48 
GPR28: 000000014a3e3500 000000014a4a1610 000000014a4a1610 0000000000000000 
NIP [00003fff890b8e8c] 0x3fff890b8e8c
LR [00003fff89323150] 0x3fff89323150
--- interrupt: c00
[...]
Comment 8 Erhard F. 2022-12-18 23:21:22 UTC
Created attachment 303425 [details]
kernel .config (6.1.0, PowerMac G5 11,2)
Comment 9 Erhard F. 2023-12-31 18:48:01 UTC
Have not seen this on my G5 and the Talos II since some kernel releases.

Closing as obsolete.