Bug#1104460: [regression 6.1.y] discard/TRIM through RAID10 blocking

[Yu Kuai]

Hi,

在 2025/04/30 23:55, Salvatore Bonaccorso 写道:

Hi

We got a regression report in Debian after the update from 6.1.133 to
6.1.135. Melvin is reporting that discard/trimm trhough a RAID10 array
stalls idefintively. The full report is inlined below and originates
from https://bugs.debian.org/1104460 .

On Wed, Apr 30, 2025 at 04:46:50PM +0200, Melvin Vermeeren wrote:

Package: src:linux
Version: 6.1.135-1
Severity: important
Tags: upstream
X-Debbugs-Cc: vermee...@vermwa.re

Dear Maintainer,

Upgrading from linux-image-6.1.0-33-powerpc64le (6.1.133-1) to
linux-image-6.1.0-34-powerpc64le (6.1.135-1) it appears there is a
serious regression bug related to discard/TRIM through a RAID10 array.
This only affects RAID10, RAID1 array on the same SSD device is not
affected. Array in question is a fairly standard RAID10 in 2far layout.

md127 : active raid10 dm-1[2] dm-0[0]
       1872188416 blocks super 1.2 512K chunks 2 far-copies [2/2] [UU]
       bitmap: 1/1 pages [64KB], 65536KB chunk

Any discard operation will result in quite a long kernel error. The
calling process will either segfault (swapon) or, more likely, be stuck
forever (Qemu, fstrim) in the D state per htop. The iostat utility
reports a %util of 100% for any device on top of (directly or
indirectly) of the RAID10 device, despite there being no read or write
requests to the devices or any other acitivty.

Stuck processes cannot be terminated or killed. Attempting to reboot
normally will result in a stuck machine on shutdown, so only a
REISUB-style reboot will work via procfs sysrq.

I have briefly diffed and inspected commits between the two kernel
versions and I suspect the commit below may be at fault. Do keep in mind
I have not verified this in any way, so I may be wrong.

https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=4a05f7ae33716d996c5ce56478a36a3ede1d76f2

Thanks for the report, the commit relied on another commit
820455238366 ("md/raid10: switch to use md_account_bio() for io
accounting"), and it's wrong for v6.1. I'll send a revert soon.

Thanks,
Kuai

Considering this is shipped as part of a stable security update I
consider it quite a serious bug. Affected hosts will not boot up
cleanly, may not have swap, processes will freeze upon discard and clean
reboot it also not possible.

More logs available upon request.

Many thanks,

Melvin Vermeeren.

-- Package-specific info:
** Version:
Linux version 6.1.0-34-powerpc64le (debian-kernel@lists.debian.org) (gcc-12 
(Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40) #1 SMP Debian 
6.1.135-1 (2025-04-25)

** Command line:
root=/dev/mapper/...-root ro quiet

** Not tainted

** Kernel log:
# /etc/fstab entry
/dev/.../swap none swap sw,discard=once 0 0

~# swapon -va
swapon: /dev/mapper/...-swap: found signature [pagesize=65536, signature=swap]
swapon: /dev/mapper/...-swap: pagesize=65536, swapsize=17179869184, 
devsize=17179869184
swapon /dev/mapper/...-swap
Segmentation fault

~# dmesg
...
[  223.017257] kernel tried to execute user page (0) - exploit attempt? (uid: 0)
[  223.017287] BUG: Unable to handle kernel instruction fetch (NULL pointer?)
[  223.017301] Faulting instruction address: 0x00000000
[  223.017326] Oops: Kernel access of bad area, sig: 11 [#1]
[  223.017338] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA PowerNV
[  223.017365] Modules linked in: bridge stp llc binfmt_misc nft_connlimit 
nf_conncount ast drm_vram_helper drm_ttm_helper ofpart ipmi_powernv ttm 
ipmi_devintf powernv_flash at24 mtd ipmi_msghandler opal_prd regmap_i2c 
drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops i2c_algo_bit sg 
nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nf_conntrack 
nf_defrag_ipv6 nf_defrag_ipv4 nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib 
nf_tables nfnetlink drm loop fuse drm_panel_orientation_quirks configfs 
ip_tables x_tables autofs4 ext4 crc16 mbcache jbd2 dm_crypt dm_integrity 
dm_bufio dm_mod macvlan raid10 raid456 async_raid6_recov async_memcpy async_pq 
async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath 
linear md_mod sd_mod t10_pi crc64_rocksoft_generic crc64_rocksoft crc_t10dif 
crct10dif_generic crc64 crct10dif_common xhci_pci xts ecb xhci_hcd ctr 
vmx_crypto gf128mul crc32c_vpmsum tg3 mpt3sas usbcore raid_class libphy 
scsi_transport_sas usb_common
[  223.017812] CPU: 8 PID: 10609 Comm: swapon Not tainted 6.1.0-34-powerpc64le 
#1  Debian 6.1.135-1
[  223.017844] Hardware name: T2P9D01 REV 1.01 POWER9 0x4e1202 
opal:skiboot-bc106a0 PowerNV
[  223.017879] NIP:  0000000000000000 LR: c0000000003efe70 CTR: 0000000000000000
[  223.017926] REGS: c0000000276cf200 TRAP: 0400   Not tainted  
(6.1.0-34-powerpc64le Debian 6.1.135-1)
[  223.017979] MSR:  900000004280b033 <SF,HV,VEC,VSX,EE,FP,ME,IR,DR,RI,LE>  CR: 
24004480  XER: 00000004
[  223.018060] CFAR: c0000000003efe6c IRQMASK: 0
                GPR00: c0000000003efec4 c0000000276cf4a0 c000000001148100 
0000000000092800
                GPR04: 0000000000000000 0000000000000003 0000000000000c00 
c00000000296e700
                GPR08: c00000000c0e9700 00000c0000090800 0000000000000000 
0000000000002000
                GPR12: 0000000000000000 c000001ffffd9800 c0000000446b8c00 
0000000000000000
                GPR16: 0000000000000400 0000000000000000 0000000000000001 
000000000000c812
                GPR20: 000000000000c911 c0000000170c5700 c00000000296e718 
c00000000296e3f0
                GPR24: 0000000000000000 00000000000003ff 0000000000000000 
0000000000000c00
                GPR28: c000200009e2dd00 c00000000296e718 00000c0000092800 
0000000000092c00
[  223.018372] NIP [0000000000000000] 0x0
[  223.018397] LR [c0000000003efe70] mempool_alloc+0xa0/0x210
[  223.018435] Call Trace:
[  223.018453] [c0000000276cf4a0] [c0000000003efec4] mempool_alloc+0xf4/0x210 
(unreliable)
[  223.018507] [c0000000276cf520] [c000000000743bf8] 
bio_alloc_bioset+0x368/0x510
[  223.018552] [c0000000276cf5a0] [c000000000743e74] bio_alloc_clone+0x44/0xa0
[  223.018601] [c0000000276cf5e0] [c008000015793adc] md_account_bio+0x54/0xb0 
[md_mod]
[  223.018655] [c0000000276cf610] [c00800001567778c] 
raid10_make_request+0xc54/0x1040 [raid10]
[  223.018687] [c0000000276cf770] [c00800001579a290] 
md_handle_request+0x198/0x380 [md_mod]
[  223.018735] [c0000000276cf800] [c00000000074c32c] __submit_bio+0x9c/0x250
[  223.018773] [c0000000276cf840] [c00000000074ca88] 
submit_bio_noacct_nocheck+0x178/0x3f0
[  223.018825] [c0000000276cf8b0] [c000000000743e08] blk_next_bio+0x68/0x90
[  223.018863] [c0000000276cf8e0] [c000000000758c60] 
__blkdev_issue_discard+0x180/0x280
[  223.018898] [c0000000276cf980] [c000000000758de8] 
blkdev_issue_discard+0x88/0x120
[  223.018927] [c0000000276cfa00] [c0000000004a9e8c] sys_swapon+0x11dc/0x18a0
[  223.018971] [c0000000276cfb50] [c00000000002b038] 
system_call_exception+0x138/0x260
[  223.019015] [c0000000276cfe10] [c00000000000c0f0] 
system_call_vectored_common+0xf0/0x280
[  223.019058] --- interrupt: 3000 at 0x7fff95146770
[  223.019095] NIP:  00007fff95146770 LR: 00007fff95146770 CTR: 0000000000000000
[  223.019132] REGS: c0000000276cfe80 TRAP: 3000   Not tainted  
(6.1.0-34-powerpc64le Debian 6.1.135-1)
[  223.019182] MSR:  900000000280f033 <SF,HV,VEC,VSX,EE,PR,FP,ME,IR,DR,RI,LE>  
CR: 48002481  XER: 00000000
[  223.019267] IRQMASK: 0
                GPR00: 0000000000000057 00007fffdca2ace0 00007fff95256f00 
00000001220a1c20
                GPR04: 0000000000030000 000000000000001e 000000000000000a 
000000000000000a
                GPR08: 0000000000000000 0000000000000000 0000000000000000 
0000000000000000
                GPR12: 0000000000000000 00007fff955dcbc0 0000000000000000 
0000000000000000
                GPR16: 0000000000000000 00000001104066b0 00007fffdca2afc8 
000000011040cbd0
                GPR20: 000000011040cbd8 0000000000000000 0000000000010000 
00007fffdca2aff0
                GPR24: 00007fffdca2afd0 0000000000000003 0000000000030000 
0000000400000000
                GPR28: 00000001220a1c20 000000000000fff6 00000001220a30a0 
0000000000100000
[  223.019542] NIP [00007fff95146770] 0x7fff95146770
[  223.019568] LR [00007fff95146770] 0x7fff95146770
[  223.019595] --- interrupt: 3000
[  223.019604] Instruction dump:
[  223.019626] XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX 
XXXXXXXX
[  223.019665] XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX 
XXXXXXXX
[  223.019712] ---[ end trace 0000000000000000 ]---

[  224.623456] note: swapon[10609] exited with irqs disabled
[  224.623483] ------------[ cut here ]------------
[  224.623502] WARNING: CPU: 8 PID: 10609 at kernel/exit.c:816 
do_exit+0x94/0xbc0
[  224.623516] Modules linked in: bridge stp llc binfmt_misc nft_connlimit 
nf_conncount ast drm_vram_helper drm_ttm_helper ofpart ipmi_powernv ttm 
ipmi_devintf powernv_flash at24 mtd ipmi_msghandler opal_prd regmap_i2c 
drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops i2c_algo_bit sg 
nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nf_conntrack 
nf_defrag_ipv6 nf_defrag_ipv4 nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib 
nf_tables nfnetlink drm loop fuse drm_panel_orientation_quirks configfs 
ip_tables x_tables autofs4 ext4 crc16 mbcache jbd2 dm_crypt dm_integrity 
dm_bufio dm_mod macvlan raid10 raid456 async_raid6_recov async_memcpy async_pq 
async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0 multipath 
linear md_mod sd_mod t10_pi crc64_rocksoft_generic crc64_rocksoft crc_t10dif 
crct10dif_generic crc64 crct10dif_common xhci_pci xts ecb xhci_hcd ctr 
vmx_crypto gf128mul crc32c_vpmsum tg3 mpt3sas usbcore raid_class libphy 
scsi_transport_sas usb_common
[  224.623825] CPU: 8 PID: 10609 Comm: swapon Tainted: G      D            
6.1.0-34-powerpc64le #1  Debian 6.1.135-1
[  224.623860] Hardware name: T2P9D01 REV 1.01 POWER9 0x4e1202 
opal:skiboot-bc106a0 PowerNV
[  224.623892] NIP:  c000000000140fa4 LR: c000000000140fa0 CTR: 0000000000000000
[  224.623935] REGS: c0000000276cecb0 TRAP: 0700   Tainted: G      D            
 (6.1.0-34-powerpc64le Debian 6.1.135-1)
[  224.623969] MSR:  9000000002029033 <SF,HV,VEC,EE,ME,IR,DR,RI,LE>  CR: 
24004222  XER: 00000004
[  224.624012] CFAR: c00000000013ea68 IRQMASK: 0
                GPR00: c000000000140fa0 c0000000276cef50 c000000001148100 
0000000000000000
                GPR04: 0000000000000000 c0000000276cee20 c0000000276cee18 
0000001ffb000000
                GPR08: 0000000000000027 c0000000276cf9b0 0000000000000000 
0000000000004000
                GPR12: 0000000031c40000 c000001ffffd9800 c0000000446b8c00 
0000000000000000
                GPR16: 0000000000000400 0000000000000000 0000000000000001 
000000000000c812
                GPR20: 000000000000c911 c0000000170c5700 c00000000296e718 
c00000000296e3f0
                GPR24: 0000000000000000 00000000000003ff 0000000000000000 
0000000000000c00
                GPR28: 000000000000000b c00000001ce25d80 c000000078409c00 
c000000026529d80
[  224.624208] NIP [c000000000140fa4] do_exit+0x94/0xbc0
[  224.624239] LR [c000000000140fa0] do_exit+0x90/0xbc0
[  224.624269] Call Trace:
[  224.624274] [c0000000276cef50] [c000000000140fa0] do_exit+0x90/0xbc0 
(unreliable)
[  224.624308] [c0000000276cf020] [c000000000141b80] make_task_dead+0xb0/0x1f0
[  224.624320] [c0000000276cf0a0] [c000000000025718] oops_end+0x188/0x1c0
[  224.624341] [c0000000276cf120] [c00000000007f72c] 
__bad_page_fault+0x18c/0x1b0
[  224.624375] [c0000000276cf190] [c000000000008cd4] 
instruction_access_common_virt+0x194/0x1a0
[  224.624421] --- interrupt: 400 at 0x0
[  224.624438] NIP:  0000000000000000 LR: c0000000003efe70 CTR: 0000000000000000
[  224.624471] REGS: c0000000276cf200 TRAP: 0400   Tainted: G      D            
 (6.1.0-34-powerpc64le Debian 6.1.135-1)
[  224.624507] MSR:  900000004280b033 <SF,HV,VEC,VSX,EE,FP,ME,IR,DR,RI,LE>  CR: 
24004480  XER: 00000004
[  224.624544] CFAR: c0000000003efe6c IRQMASK: 0
                GPR00: c0000000003efec4 c0000000276cf4a0 c000000001148100 
0000000000092800
                GPR04: 0000000000000000 0000000000000003 0000000000000c00 
c00000000296e700
                GPR08: c00000000c0e9700 00000c0000090800 0000000000000000 
0000000000002000
                GPR12: 0000000000000000 c000001ffffd9800 c0000000446b8c00 
0000000000000000
                GPR16: 0000000000000400 0000000000000000 0000000000000001 
000000000000c812
                GPR20: 000000000000c911 c0000000170c5700 c00000000296e718 
c00000000296e3f0
                GPR24: 0000000000000000 00000000000003ff 0000000000000000 
0000000000000c00
                GPR28: c000200009e2dd00 c00000000296e718 00000c0000092800 
0000000000092c00
[  224.624732] NIP [0000000000000000] 0x0
[  224.624749] LR [c0000000003efe70] mempool_alloc+0xa0/0x210
[  224.624771] --- interrupt: 400
[  224.624789] [c0000000276cf4a0] [c0000000003efec4] mempool_alloc+0xf4/0x210 
(unreliable)
[  224.624823] [c0000000276cf520] [c000000000743bf8] 
bio_alloc_bioset+0x368/0x510
[  224.624859] [c0000000276cf5a0] [c000000000743e74] bio_alloc_clone+0x44/0xa0
[  224.624892] [c0000000276cf5e0] [c008000015793adc] md_account_bio+0x54/0xb0 
[md_mod]
[  224.624930] [c0000000276cf610] [c00800001567778c] 
raid10_make_request+0xc54/0x1040 [raid10]
[  224.624964] [c0000000276cf770] [c00800001579a290] 
md_handle_request+0x198/0x380 [md_mod]
[  224.624997] [c0000000276cf800] [c00000000074c32c] __submit_bio+0x9c/0x250
[  224.625018] [c0000000276cf840] [c00000000074ca88] 
submit_bio_noacct_nocheck+0x178/0x3f0
[  224.625043] [c0000000276cf8b0] [c000000000743e08] blk_next_bio+0x68/0x90
[  224.625066] [c0000000276cf8e0] [c000000000758c60] 
__blkdev_issue_discard+0x180/0x280
[  224.625091] [c0000000276cf980] [c000000000758de8] 
blkdev_issue_discard+0x88/0x120
[  224.625115] [c0000000276cfa00] [c0000000004a9e8c] sys_swapon+0x11dc/0x18a0
[  224.625139] [c0000000276cfb50] [c00000000002b038] 
system_call_exception+0x138/0x260
[  224.625164] [c0000000276cfe10] [c00000000000c0f0] 
system_call_vectored_common+0xf0/0x280
[  224.625201] --- interrupt: 3000 at 0x7fff95146770
[  224.625270] NIP:  00007fff95146770 LR: 00007fff95146770 CTR: 0000000000000000
[  224.625367] REGS: c0000000276cfe80 TRAP: 3000   Tainted: G      D            
 (6.1.0-34-powerpc64le Debian 6.1.135-1)
[  224.625458] MSR:  900000000000f033 <SF,HV,EE,PR,FP,ME,IR,DR,RI,LE>  CR: 
48002481  XER: 00000000
[  224.625570] IRQMASK: 0
                GPR00: 0000000000000057 00007fffdca2ace0 00007fff95256f00 
00000001220a1c20
                GPR04: 0000000000030000 000000000000001e 000000000000000a 
000000000000000a
                GPR08: 0000000000000000 0000000000000000 0000000000000000 
0000000000000000
                GPR12: 0000000000000000 00007fff955dcbc0 0000000000000000 
0000000000000000
                GPR16: 0000000000000000 00000001104066b0 00007fffdca2afc8 
000000011040cbd0
                GPR20: 000000011040cbd8 0000000000000000 0000000000010000 
00007fffdca2aff0
                GPR24: 00007fffdca2afd0 0000000000000003 0000000000030000 
0000000400000000
                GPR28: 00000001220a1c20 000000000000fff6 00000001220a30a0 
0000000000100000
[  224.626325] NIP [00007fff95146770] 0x7fff95146770
[  224.626388] LR [00007fff95146770] 0x7fff95146770
[  224.626522] --- interrupt: 3000
[  224.626568] Instruction dump:
[  224.626587] 60000000 813f000c 3929ffff 2c090000 913f000c 40820010 813f0074 
71290004
[  224.626680] 4182074c 7fa3eb78 4bffda7d e93e0b10 <0b090000> e87e0a48 48c7dd0d 
60000000
[  224.626786] ---[ end trace 0000000000000000 ]---

Does this ring a bell?

Melvin, the same change went as well in other stable series, 6.6.88,
6.12.25, 6.14.4, can you test e.g. 6.12.25-1 in Debian as well from
unstable to see if the regression is there as well?

Might you be able to bisect the upstream stable series between 6.1.133
to 6.1.135 to really confirm the mentioned commit is the one breaking?

Regards,
Salvatore

.