Re: [PATCH v4 4/4] blk-flush: reuse rq queuelist in flush state machine

[Chengming Zhou <chengming.zhou@linux.dev>]

On 2024/5/28 00:04, Friedrich Weber wrote:
> Hi Chengming,
> 
> Thank you for taking a look at this!
> 
> On 27/05/2024 07:09, Chengming Zhou wrote:
>>> I've used this reproducer for a bisect, which produced
>>>
>>>  81ada09cc25e (blk-flush: reuse rq queuelist in flush state machine)
>>>
>>> as the first commit with which I can reproduce the crashes. I'm not 100%
>>> sure it is this one because the reproducer is a bit flaky. But it does
>>> sound plausible, as the commit is included in our 6.8 kernel, and
>>> touches `queuelist` which is AFAICT where blk_flush_complete_seq
>>> dereferences the NULL pointer.
>>
>> Ok, it will be better that I can reproduce it locally, will try later.
> 
> Interestingly, so far I haven't been able to reproduce the crash when
> generating IO on the host itself, I only got crashes when generating IO
> in a QEMU VM.
> 
> The reproducer in more detail:

Thanks for these details, I will try to setup and reproduce when I back to work.

> 
> - Compile Linux 6.9 with CONFIG_FAULT_INJECTION,
[...]
>>
>> BUG shows it panic on 0000000000000008, not sure what it's accessing then,
>> does it means rq->queuelist.next == 0 or something? Could you use add2line
>> to show the exact source code line that panic? I use blk_flush_complete_seq+0x296/0x2e0
>> and get block/blk-flush.c:190, which is "fq->flush_data_in_flight++;",
>> obviously fq can't be NULL. (I'm using the v6.9 kernel)
> 
> Sorry for the confusion, the crash dump was from a kernel compiled at
> 81ada09cc25e -- with 6.9, the offset seems to be different. See [2] for
> a kernel 6.9 crash dump.
> 
> I don't know too much about kernel debugging, but I tried to get
> something useful out of addr2line:
> 
> # addr2line -f -e /usr/lib/debug/vmlinux-6.9.0-debug2
> blk_flush_complete_seq+0x291/0x2d0
> __list_del
> /[...]./include/linux/list.h:195
> 
> I tried to find the relevant portions in `objdump -SD blk-flush.o`, see
> [3]. If I'm not mistaken, blk_flush_complete_seq+0x291 should point to
> 
> 351:   48 89 4f 08             mov    %rcx,0x8(%rdi)
> 
> To me this looks like part of
> 
> 	list_move_tail(&rq->queuelist, pending);
> 
> What do you think?

Yeah, it seems correct, so the rq->queuelist.next == NULL. It can't be NULL
if went through REQ_FSEQ_POSTFLUSH, so it must be REQ_FSEQ_PREFLUSH. It means
we allocated a request but its queuelist is not initialized or corrupted?

Anyway, I will use below changes for debugging when reproduce, and you could
also try this to see if we could get something useful. :)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 3b4df8e5ac9e..6e3a6cd7739d 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2989,6 +2989,8 @@ void blk_mq_submit_bio(struct bio *bio)
                blk_mq_use_cached_rq(rq, plug, bio);
        }

+       BUG_ON(rq->queuelist.next == NULL);
+
        trace_block_getrq(bio);

        rq_qos_track(q, rq, bio);
@@ -3006,6 +3008,8 @@ void blk_mq_submit_bio(struct bio *bio)
        if (bio_zone_write_plugging(bio))
                blk_zone_write_plug_init_request(rq);

+       BUG_ON(rq->queuelist.next == NULL);
+
        if (op_is_flush(bio->bi_opf) && blk_insert_flush(rq))
                return;

Thanks!

> 
> FWIW, I've also compiled a 6.9 kernel with CONFIG_LIST_DEBUG, and when
> running the reproducer it started reporting corruptions, see [4] for the
> first one. It did not crash, though, maybe because CONFIG_LIST_DEBUG
> prevents the NULL pointer dereference?
> 
> Hope this helps! If I can provide anything else, just let me know.
> 
> Best wishes,
> 
> Friedrich
> 
> [0]
> 
> # mdadm --detail /dev/md0
> /dev/md0:
>            Version : 1.2
>      Creation Time : Wed May 22 10:14:40 2024
>         Raid Level : raid1
>         Array Size : 33534976 (31.98 GiB 34.34 GB)
>      Used Dev Size : 33534976 (31.98 GiB 34.34 GB)
>       Raid Devices : 2
>      Total Devices : 2
>        Persistence : Superblock is persistent
> 
>      Intent Bitmap : Internal
> 
>        Update Time : Mon May 27 17:31:02 2024
>              State : active
>     Active Devices : 2
>    Working Devices : 2
>     Failed Devices : 0
>      Spare Devices : 0
> 
> Consistency Policy : bitmap
> 
>               Name : reproflushfull:0  (local to host reproflushfull)
>               UUID : fda4a959:d2dd0bef:d7094fb1:c6e3174c
>             Events : 749
> 
>     Number   Major   Minor   RaidDevice State
>        0       8        1        0      active sync   /dev/sda1
>        1       8       17        1      active sync   /dev/sdb1
> 
> [1]
> 
> ./qemu-8.2.2/qemu-system-x86_64 \
>   -accel kvm \
>   -name 'pve,debug-threads=on' \
>   -chardev
> 'socket,id=qmp,path=/var/run/qemu-server/100.qmp,server=on,wait=off' \
>   -mon 'chardev=qmp,mode=control' \
>   -chardev 'socket,id=qmp-event,path=/var/run/qmeventd.sock,reconnect=5' \
>   -mon 'chardev=qmp-event,mode=control' \
>   -pidfile /var/run/qemu-server/100.pid \
>   -smbios 'type=1,uuid=25a3012b-e72a-4121-9e57-f6f5a40ebe62' \
>   -smp '4,sockets=1,cores=4,maxcpus=4' \
>   -nodefaults \
>   -vnc 'unix:/var/run/qemu-server/100.vnc,password=on' \
>   -cpu host,+kvm_pv_eoi,+kvm_pv_unhalt \
>   -m 4096 \
>   -object 'iothread,id=iothread-virtioscsi0' \
>   -device 'pci-bridge,id=pci.1,chassis_nr=1,bus=pci.0,addr=0x1e' \
>   -device 'pci-bridge,id=pci.2,chassis_nr=2,bus=pci.0,addr=0x1f' \
>   -device 'pci-bridge,id=pci.3,chassis_nr=3,bus=pci.0,addr=0x5' \
>   -device 'vmgenid,guid=ab6d50e3-d574-4ba8-bb0c-3c0bbcc9cd2e' \
>   -device 'piix3-usb-uhci,id=uhci,bus=pci.0,addr=0x1.0x2' \
>   -device 'VGA,id=vga,bus=pci.0,addr=0x2' \
>   -device
> 'virtio-scsi-pci,id=virtioscsi0,bus=pci.3,addr=0x1,iothread=iothread-virtioscsi0'
> \
>   -drive
> 'file=/var/lib/vz/images/100/vm-100-disk-0.qcow2,if=none,id=drive-scsi0,format=qcow2,cache=none,aio=io_uring,detect-zeroes=on'
> \
>   -device
> 'scsi-hd,bus=virtioscsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0,id=scsi0,bootindex=100'
> \
>   -machine 'type=pc'
> 
> [2]
> 
> [   85.282301] BUG: kernel NULL pointer dereference, address:
> 0000000000000008
> [   85.283454] #PF: supervisor write access in kernel mode
> [   85.284289] #PF: error_code(0x0002) - not-present page
> [   85.285087] PGD 0 P4D 0
> [   85.285500] Oops: 0002 [#1] PREEMPT SMP NOPTI
> [   85.286211] CPU: 0 PID: 794 Comm: kvm Tainted: G            E
> 6.9.0-debug2 #27
> [   85.287420] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
> BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
> [   85.289177] RIP: 0010:blk_flush_complete_seq+0x291/0x2d0
> [   85.289994] Code: 0f b6 f6 49 8d 56 01 49 c1 e6 04 4d 01 ee 48 c1 e2
> 04 49 8b 4e 10 4c 01 ea 48 39 ca 74 2b 48 8b 4b 50 48 8b 7b 48 48 8d 73
> 48 <48> 89 4f 08 48 89 39 49 8b 4e 18 49 89 76 18 48 89 53 48 48 89 4b
> [   85.292894] RSP: 0018:ffff9c08c07f3998 EFLAGS: 00010046
> [   85.293714] RAX: 0000000000000000 RBX: ffff8b9c8abad000 RCX:
> ffff8b9c8abad048
> [   85.294809] RDX: ffff8b9c80a3d6a0 RSI: ffff8b9c8abad048 RDI:
> 0000000000000000
> [   85.295921] RBP: ffff9c08c07f39d8 R08: 0000000000000000 R09:
> 0000000000000000
> [   85.297111] R10: 0000000000000000 R11: 0000000000000000 R12:
> 0000000000009801
> [   85.298211] R13: ffff8b9c80a3d680 R14: ffff8b9c80a3d690 R15:
> ffff8b9c8341ddc0
> [   85.299353] FS:  0000776683e006c0(0000) GS:ffff8b9db7a00000(0000)
> knlGS:0000000000000000
> [   85.300825] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [   85.301712] CR2: 0000000000000008 CR3: 000000010e6e4001 CR4:
> 0000000000372ef0
> [   85.302810] Call Trace:
> [   85.303242]  <TASK>
> [   85.303597]  ? show_regs+0x6c/0x80
> [   85.304169]  ? __die+0x24/0x80
> [   85.304671]  ? page_fault_oops+0x175/0x5b0
> [   85.305326]  ? do_user_addr_fault+0x311/0x680
> [   85.306012]  ? exc_page_fault+0x82/0x1b0
> [   85.306657]  ? asm_exc_page_fault+0x27/0x30
> [   85.307297]  ? blk_flush_complete_seq+0x291/0x2d0
> [   85.308023]  ? __blk_mq_alloc_requests+0x251/0x540
> [   85.308785]  ? wbt_wait+0x33/0x100
> [   85.309620]  blk_insert_flush+0xce/0x220
> [   85.310307]  blk_mq_submit_bio+0x5cd/0x730
> [   85.310948]  __submit_bio+0xb3/0x1c0
> [   85.311535]  submit_bio_noacct_nocheck+0x2fc/0x3d0
> [   85.312296]  submit_bio_noacct+0x1ba/0x6b0
> [   85.312934]  ? ext4_file_write_iter+0x3b1/0x7e0
> [   85.313663]  submit_bio+0xb1/0x110
> [   85.314220]  md_super_write+0xcf/0x110
> [   85.314816]  write_sb_page+0x148/0x300
> [   85.315422]  filemap_write_page+0x5b/0x70
> [   85.316058]  md_bitmap_unplug+0x99/0x1f0
> [   85.316676]  flush_bio_list+0x107/0x110 [raid1]
> [   85.317399]  raid1_unplug+0x3c/0xf0 [raid1]
> [   85.318056]  __blk_flush_plug+0xbe/0x140
> [   85.318673]  blk_finish_plug+0x30/0x50
> [   85.319268]  io_submit_sqes+0x4c4/0x6c0
> [   85.319872]  __do_sys_io_uring_enter+0x2f2/0x640
> [   85.320590]  ? blk_mq_complete_request+0x26/0x40
> [   85.321326]  __x64_sys_io_uring_enter+0x22/0x40
> [   85.322044]  x64_sys_call+0x20b9/0x24b0
> [   85.322656]  do_syscall_64+0x80/0x170
> [   85.323243]  ? vring_interrupt+0x94/0x110
> [   85.323878]  ? __x64_sys_ppoll+0xf2/0x170
> [   85.324501]  ? handle_irq_event+0x52/0x80
> [   85.325103]  ? _raw_spin_unlock+0xe/0x40
> [   85.325728]  ? handle_edge_irq+0xda/0x250
> [   85.326347]  ? irqentry_exit_to_user_mode+0x76/0x270
> [   85.327114]  ? irqentry_exit+0x43/0x50
> [   85.327703]  ? clear_bhb_loop+0x15/0x70
> [   85.328286]  ? clear_bhb_loop+0x15/0x70
> [   85.328897]  ? clear_bhb_loop+0x15/0x70
> [   85.329541]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
> [   85.330326] RIP: 0033:0x776695660b95
> [   85.330908] Code: 00 00 00 44 89 d0 41 b9 08 00 00 00 83 c8 10 f6 87
> d0 00 00 00 01 8b bf cc 00 00 00 44 0f 45 d0 45 31 c0 b8 aa 01 00 00 0f
> 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 41 83 e2 02 74 c2 f0 48 83 0c 24
> [   85.333736] RSP: 002b:0000776683dfafd8 EFLAGS: 00000246 ORIG_RAX:
> 00000000000001aa
> [   85.334911] RAX: ffffffffffffffda RBX: 000077667c0039f0 RCX:
> 0000776695660b95
> [   85.335999] RDX: 0000000000000000 RSI: 0000000000000003 RDI:
> 0000000000000033
> [   85.337111] RBP: 000077667c0039f8 R08: 0000000000000000 R09:
> 0000000000000008
> [   85.338210] R10: 0000000000000000 R11: 0000000000000246 R12:
> 000077667c003ae0
> [   85.339304] R13: 0000000000000000 R14: 000064175d5afc68 R15:
> 000064178a3f9450
> [   85.340408]  </TASK>
> [   85.340772] Modules linked in: tcp_diag(E) inet_diag(E) veth(E)
> cmac(E) nls_utf8(E) cifs(E) cifs_arc4(E) nls_ucs2_utils(E) rdma_cm(E)
> iw_cm(E) ib_cm(E) ib_core(E) cifs_md4(E) netfs(E) ebtable_filter(E)
> ebtables(E) ip_set(E) ip6table_raw(E) iptable_raw(E) ip6table_filter(E)
> ip6_tables(E) iptable_filter(E) nf_tables(E) softdog(E) sunrpc(E)
> binfmt_misc(E) bonding(E) tls(E) nfnetlink_log(E) nfnetlink(E)
> intel_rapl_msr(E) intel_rapl_common(E) intel_uncore_frequency_common(E)
> intel_pmc_core(E) intel_vsec(E) pmt_telemetry(E) pmt_class(E)
> kvm_intel(E) kvm(E) hid_generic(E) crct10dif_pclmul(E)
> polyval_clmulni(E) polyval_generic(E) ghash_clmulni_intel(E)
> sha256_ssse3(E) sha1_ssse3(E) aesni_intel(E) crypto_simd(E) usbhid(E)
> cryptd(E) hid(E) rapl(E) pcspkr(E) vmgenid(E) joydev(E) input_leds(E)
> serio_raw(E) mac_hid(E) vhost_net(E) vhost(E) vhost_iotlb(E) tap(E)
> efi_pstore(E) dmi_sysfs(E) qemu_fw_cfg(E) ip_tables(E) x_tables(E)
> autofs4(E) raid10(E) raid456(E) async_raid6_recov(E) async_memcpy(E)
> async_pq(E) async_xor(E) async_tx(E)
> [   85.340859]  xor(E) raid6_pq(E) libcrc32c(E) raid0(E) raid1(E)
> crc32_pclmul(E) bochs(E) drm_vram_helper(E) drm_ttm_helper(E) psmouse(E)
> uhci_hcd(E) ehci_hcd(E) ttm(E) i2c_piix4(E) pata_acpi(E) floppy(E)
> [   85.357137] CR2: 0000000000000008
> [   85.358209] ---[ end trace 0000000000000000 ]---
> [   85.358926] RIP: 0010:blk_flush_complete_seq+0x291/0x2d0
> [   85.360004] Code: 0f b6 f6 49 8d 56 01 49 c1 e6 04 4d 01 ee 48 c1 e2
> 04 49 8b 4e 10 4c 01 ea 48 39 ca 74 2b 48 8b 4b 50 48 8b 7b 48 48 8d 73
> 48 <48> 89 4f 08 48 89 39 49 8b 4e 18 49 89 76 18 48 89 53 48 48 89 4b
> [   85.362891] RSP: 0018:ffff9c08c07f3998 EFLAGS: 00010046
> [   85.363695] RAX: 0000000000000000 RBX: ffff8b9c8abad000 RCX:
> ffff8b9c8abad048
> [   85.364800] RDX: ffff8b9c80a3d6a0 RSI: ffff8b9c8abad048 RDI:
> 0000000000000000
> [   85.365902] RBP: ffff9c08c07f39d8 R08: 0000000000000000 R09:
> 0000000000000000
> [   85.366993] R10: 0000000000000000 R11: 0000000000000000 R12:
> 0000000000009801
> [   85.368089] R13: ffff8b9c80a3d680 R14: ffff8b9c80a3d690 R15:
> ffff8b9c8341ddc0
> [   85.369190] FS:  0000776683e006c0(0000) GS:ffff8b9db7a00000(0000)
> knlGS:0000000000000000
> [   85.370440] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [   85.371327] CR2: 0000000000000008 CR3: 000000010e6e4001 CR4:
> 0000000000372ef0
> [   85.372440] note: kvm[794] exited with irqs disabled
> [   85.373340] note: kvm[794] exited with preempt_count 1
> [   85.374238] ------------[ cut here ]------------
> [   85.374943] WARNING: CPU: 0 PID: 794 at kernel/exit.c:827
> do_exit+0x8a2/0xab0
> [   85.376047] Modules linked in: tcp_diag(E) inet_diag(E) veth(E)
> cmac(E) nls_utf8(E) cifs(E) cifs_arc4(E) nls_ucs2_utils(E) rdma_cm(E)
> iw_cm(E) ib_cm(E) ib_core(E) cifs_md4(E) netfs(E) ebtable_filter(E)
> ebtables(E) ip_set(E) ip6table_raw(E) iptable_raw(E) ip6table_filter(E)
> ip6_tables(E) iptable_filter(E) nf_tables(E) softdog(E) sunrpc(E)
> binfmt_misc(E) bonding(E) tls(E) nfnetlink_log(E) nfnetlink(E)
> intel_rapl_msr(E) intel_rapl_common(E) intel_uncore_frequency_common(E)
> intel_pmc_core(E) intel_vsec(E) pmt_telemetry(E) pmt_class(E)
> kvm_intel(E) kvm(E) hid_generic(E) crct10dif_pclmul(E)
> polyval_clmulni(E) polyval_generic(E) ghash_clmulni_intel(E)
> sha256_ssse3(E) sha1_ssse3(E) aesni_intel(E) crypto_simd(E) usbhid(E)
> cryptd(E) hid(E) rapl(E) pcspkr(E) vmgenid(E) joydev(E) input_leds(E)
> serio_raw(E) mac_hid(E) vhost_net(E) vhost(E) vhost_iotlb(E) tap(E)
> efi_pstore(E) dmi_sysfs(E) qemu_fw_cfg(E) ip_tables(E) x_tables(E)
> autofs4(E) raid10(E) raid456(E) async_raid6_recov(E) async_memcpy(E)
> async_pq(E) async_xor(E) async_tx(E)
> [   85.376128]  xor(E) raid6_pq(E) libcrc32c(E) raid0(E) raid1(E)
> crc32_pclmul(E) bochs(E) drm_vram_helper(E) drm_ttm_helper(E) psmouse(E)
> uhci_hcd(E) ehci_hcd(E) ttm(E) i2c_piix4(E) pata_acpi(E) floppy(E)
> [   85.392395] CPU: 0 PID: 794 Comm: kvm Tainted: G      D     E
> 6.9.0-debug2 #27
> [   85.393594] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
> BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
> [   85.395347] RIP: 0010:do_exit+0x8a2/0xab0
> [   85.395975] Code: 38 0c 00 00 e9 2d fe ff ff 49 8d 7d 18 e8 b6 83 07
> 00 e9 5a f8 ff ff 48 8b bb f8 09 00 00 31 f6 e8 b3 e0 ff ff e9 c1 fd ff
> ff <0f> 0b e9 d4 f7 ff ff 0f 0b e9 8f f7 ff ff 4c 89 e6 bf 05 06 00 00
> [   85.398793] RSP: 0018:ffff9c08c07f3ec8 EFLAGS: 00010286
> [   85.399625] RAX: 0000000000000000 RBX: ffff8b9c82e90000 RCX:
> 0000000000000000
> [   85.400720] RDX: 0000000000000000 RSI: 0000000000000000 RDI:
> 0000000000000000
> 
> [3]
> 
> 00000000000000c0 <blk_flush_complete_seq>:
> {
> [...]
>        struct list_head *pending = &fq->flush_queue[fq->flush_pending_idx];
>  32a:   49 8d 56 01             lea    0x1(%r14),%rdx
>  32e:   49 c1 e6 04             shl    $0x4,%r14
>  332:   4d 01 ee                add    %r13,%r14
>  335:   48 c1 e2 04             shl    $0x4,%rdx
>         return READ_ONCE(head->next) == head;
>  339:   49 8b 4e 10             mov    0x10(%r14),%rcx
>  33d:   4c 01 ea                add    %r13,%rdx
>                 if (list_empty(pending))
>  340:   48 39 ca                cmp    %rcx,%rdx
>  343:   74 2b                   je     370 <blk_flush_complete_seq+0x2b0>
>         __list_del(entry->prev, entry->next);
>  345:   48 8b 4b 50             mov    0x50(%rbx),%rcx
>  349:   48 8b 7b 48             mov    0x48(%rbx),%rdi
>                 list_move_tail(&rq->queuelist, pending);
>  34d:   48 8d 73 48             lea    0x48(%rbx),%rsi
>         next->prev = prev;
>  351:   48 89 4f 08             mov    %rcx,0x8(%rdi)
>         WRITE_ONCE(prev->next, next);
>  355:   48 89 39                mov    %rdi,(%rcx)
>         __list_add(new, head->prev, head);
>  358:   49 8b 4e 18             mov    0x18(%r14),%rcx
>         next->prev = new;
>  35c:   49 89 76 18             mov    %rsi,0x18(%r14)
>         new->next = next;
>  360:   48 89 53 48             mov    %rdx,0x48(%rbx)
>         new->prev = prev;
>  364:   48 89 4b 50             mov    %rcx,0x50(%rbx)
>         WRITE_ONCE(prev->next, new);
>  368:   48 89 31                mov    %rsi,(%rcx)
> }
>  36b:   e9 30 fe ff ff          jmp    1a0 <blk_flush_complete_seq+0xe0>
>                         fq->flush_pending_since = jiffies;
>  370:   48 8b 0d 00 00 00 00    mov    0x0(%rip),%rcx        # 377
> <blk_flush_complete_seq+0x2b7>
>  377:   49 89 4d 08             mov    %rcx,0x8(%r13)
>  37b:   eb c8                   jmp    345 <blk_flush_complete_seq+0x285>
> 
> [4] May 27 11:12:53 reproflushfull kernel: list_del corruption.
> prev->next should be ffff8ad44ab63788, but was ffff8ad44ab63400.
> (prev=ffff8ad44ab63788)
> May 27 11:12:53 reproflushfull kernel: WARNING: CPU: 0 PID: 797 at
> lib/list_debug.c:62 __list_del_entry_valid_or_report+0xd4/0x100
> May 27 11:12:53 reproflushfull kernel: Modules linked in: veth(E)
> cmac(E) nls_utf8(E) cifs(E) cifs_arc4(E) nls_ucs2_utils(E) rdma_cm(E)
> iw_cm(E) ib_cm(E) ib_core(E) cifs_md4(E) netfs(E) ebtable_filter(E)
> ebtables(E) ip_set(E) ip6table_raw(E) iptable_raw(E) ip6table_filter(E)
> ip6_tables(E) iptable_filter(E) nf_tables(E) softdog(E) sunrpc(E)
> binfmt_misc(E) bonding(E) tls(E) nfnetlink_log(E) nfnetlink(E)
> intel_rapl_msr(E) intel_rapl_common(E) intel_uncore_frequency_common(E)
> intel_pmc_core(E) intel_vsec(E) pmt_telemetry(E) pmt_class(E)
> kvm_intel(E) kvm(E) crct10dif_pclmul(E) polyval_clmulni(E)
> polyval_generic(E) hid_generic(E) ghash_clmulni_intel(E) sha256_ssse3(E)
> sha1_ssse3(E) aesni_intel(E) crypto_simd(E) usbhid(E) cryptd(E) hid(E)
> rapl(E) pcspkr(E) vmgenid(E) joydev(E) input_leds(E) mac_hid(E)
> serio_raw(E) vhost_net(E) vhost(E) vhost_iotlb(E) tap(E) efi_pstore(E)
> dmi_sysfs(E) qemu_fw_cfg(E) ip_tables(E) x_tables(E) autofs4(E)
> raid10(E) raid456(E) async_raid6_recov(E) async_memcpy(E) async_pq(E)
> async_xor(E) async_tx(E) xor(E) raid6_pq(E)
> May 27 11:12:53 reproflushfull kernel:  libcrc32c(E) raid0(E) raid1(E)
> crc32_pclmul(E) bochs(E) psmouse(E) drm_vram_helper(E) drm_ttm_helper(E)
> uhci_hcd(E) ttm(E) i2c_piix4(E) ehci_hcd(E) pata_acpi(E) floppy(E)
> May 27 11:12:53 reproflushfull kernel: CPU: 0 PID: 797 Comm: kvm
> Tainted: G            E      6.9.0-debug #25
> May 27 11:12:53 reproflushfull kernel: Hardware name: QEMU Standard PC
> (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org
> 04/01/2014
> May 27 11:12:53 reproflushfull kernel: RIP:
> 0010:__list_del_entry_valid_or_report+0xd4/0x100
> May 27 11:12:53 reproflushfull kernel: Code: 48 89 fe 48 89 ca 48 c7 c7
> 78 77 9f a1 e8 84 3a 8e ff 0f 0b 31 c0 eb b0 48 89 fe 48 89 c2 48 c7 c7
> b0 77 9f a1 e8 6c 3a 8e ff <0f> 0b 31 c0 eb 98 48 89 d1 48 c7 c7 f8 77
> 9f a1 48 89 f2 48 89 c6
> May 27 11:12:53 reproflushfull kernel: RSP: 0018:ffffb1dd80673740
> EFLAGS: 00010046
> May 27 11:12:53 reproflushfull kernel: RAX: 0000000000000000 RBX:
> ffff8ad440be12c0 RCX: 0000000000000000
> May 27 11:12:53 reproflushfull kernel: RDX: 0000000000000000 RSI:
> 0000000000000000 RDI: 0000000000000000
> May 27 11:12:53 reproflushfull kernel: RBP: ffffb1dd80673740 R08:
> 0000000000000000 R09: 0000000000000000
> May 27 11:12:53 reproflushfull kernel: R10: 0000000000000000 R11:
> 0000000000000000 R12: ffff8ad44a8c1e00
> May 27 11:12:53 reproflushfull kernel: R13: ffff8ad440be12c0 R14:
> ffff8ad44ab63788 R15: ffff8ad44ab63740
> May 27 11:12:53 reproflushfull kernel: FS:  00007e8a67c006c0(0000)
> GS:ffff8ad577a00000(0000) knlGS:0000000000000000
> May 27 11:12:53 reproflushfull kernel: CS:  0010 DS: 0000 ES: 0000 CR0:
> 0000000080050033
> May 27 11:12:53 reproflushfull kernel: CR2: 00007e8a5801a008 CR3:
> 000000010e022001 CR4: 0000000000372ef0
> May 27 11:12:53 reproflushfull kernel: Call Trace:
> May 27 11:12:53 reproflushfull kernel:  <TASK>
> May 27 11:12:53 reproflushfull kernel:  ? show_regs+0x6c/0x80
> May 27 11:12:53 reproflushfull kernel:  ? __warn+0x88/0x140
> May 27 11:12:53 reproflushfull kernel:  ?
> __list_del_entry_valid_or_report+0xd4/0x100
> May 27 11:12:53 reproflushfull kernel:  ? report_bug+0x182/0x1b0
> May 27 11:12:53 reproflushfull kernel:  ? handle_bug+0x46/0x90
> May 27 11:12:53 reproflushfull kernel:  ? exc_invalid_op+0x18/0x80
> May 27 11:12:53 reproflushfull kernel:  ? asm_exc_invalid_op+0x1b/0x20
> May 27 11:12:53 reproflushfull kernel:  ?
> __list_del_entry_valid_or_report+0xd4/0x100
> May 27 11:12:53 reproflushfull kernel:  blk_flush_complete_seq+0x2f3/0x360
> May 27 11:12:53 reproflushfull kernel:  ? wbt_wait+0x33/0x100
> May 27 11:12:53 reproflushfull kernel:  blk_insert_flush+0xce/0x220
> May 27 11:12:53 reproflushfull kernel:  blk_mq_submit_bio+0x5cd/0x730
> May 27 11:12:53 reproflushfull kernel:  __submit_bio+0xb3/0x1c0
> May 27 11:12:53 reproflushfull kernel:
> submit_bio_noacct_nocheck+0x2fc/0x3d0
> May 27 11:12:53 reproflushfull kernel:  submit_bio_noacct+0x1ba/0x6b0
> May 27 11:12:53 reproflushfull kernel:  submit_bio+0xb1/0x110
> May 27 11:12:53 reproflushfull kernel:  md_super_write+0xcf/0x110
> May 27 11:12:53 reproflushfull kernel:  write_sb_page+0x148/0x300
> May 27 11:12:53 reproflushfull kernel:  filemap_write_page+0x5b/0x70
> May 27 11:12:53 reproflushfull kernel:  md_bitmap_unplug+0x99/0x1f0
> May 27 11:12:53 reproflushfull kernel:  flush_bio_list+0x107/0x110 [raid1]
> May 27 11:12:53 reproflushfull kernel:  raid1_unplug+0x3c/0xf0 [raid1]
> May 27 11:12:53 reproflushfull kernel:  __blk_flush_plug+0xd9/0x170
> May 27 11:12:53 reproflushfull kernel:  blk_finish_plug+0x30/0x50
> May 27 11:12:53 reproflushfull kernel:  io_submit_sqes+0x4c4/0x6c0
> May 27 11:12:53 reproflushfull kernel:  __do_sys_io_uring_enter+0x2f2/0x640
> May 27 11:12:53 reproflushfull kernel:  __x64_sys_io_uring_enter+0x22/0x40
> May 27 11:12:53 reproflushfull kernel:  x64_sys_call+0x20b9/0x24b0
> May 27 11:12:53 reproflushfull kernel:  do_syscall_64+0x80/0x170
> May 27 11:12:53 reproflushfull kernel:  ? do_mprotect_pkey+0x198/0x620
> May 27 11:12:53 reproflushfull kernel:  ?
> __memcg_slab_post_alloc_hook+0x18e/0x230
> May 27 11:12:53 reproflushfull kernel:  ? policy_nodemask+0x145/0x180
> May 27 11:12:53 reproflushfull kernel:  ?
> __mod_memcg_lruvec_state+0x87/0x120
> May 27 11:12:53 reproflushfull kernel:  ? __mod_lruvec_state+0x36/0x50
> May 27 11:12:53 reproflushfull kernel:  ? __lruvec_stat_mod_folio+0x70/0xc0
> May 27 11:12:53 reproflushfull kernel:  ? set_ptes.constprop.0+0x2b/0xb0
> May 27 11:12:53 reproflushfull kernel:  ? _raw_spin_unlock+0xe/0x40
> May 27 11:12:53 reproflushfull kernel:  ? do_anonymous_page+0x23d/0x790
> May 27 11:12:53 reproflushfull kernel:  ? __pte_offset_map+0x1c/0x1b0
> May 27 11:12:53 reproflushfull kernel:  ? __handle_mm_fault+0xc1a/0xe90
> May 27 11:12:53 reproflushfull kernel:  ? do_syscall_64+0x8c/0x170
> May 27 11:12:53 reproflushfull kernel:  ? __count_memcg_events+0x6f/0xe0
> May 27 11:12:53 reproflushfull kernel:  ?
> count_memcg_events.constprop.0+0x2a/0x50
> May 27 11:12:53 reproflushfull kernel:  ? handle_mm_fault+0xaf/0x340
> May 27 11:12:53 reproflushfull kernel:  ? do_user_addr_fault+0x365/0x680
> May 27 11:12:53 reproflushfull kernel:  ?
> irqentry_exit_to_user_mode+0x76/0x270
> May 27 11:12:53 reproflushfull kernel:  ? irqentry_exit+0x43/0x50
> May 27 11:12:53 reproflushfull kernel:  ? clear_bhb_loop+0x15/0x70
> May 27 11:12:53 reproflushfull kernel:  ? clear_bhb_loop+0x15/0x70
> May 27 11:12:53 reproflushfull kernel:  ? clear_bhb_loop+0x15/0x70
> May 27 11:12:53 reproflushfull kernel:
> entry_SYSCALL_64_after_hwframe+0x76/0x7e
> May 27 11:12:53 reproflushfull kernel: RIP: 0033:0x7e8a75069b95
> May 27 11:12:53 reproflushfull kernel: Code: 00 00 00 44 89 d0 41 b9 08
> 00 00 00 83 c8 10 f6 87 d0 00 00 00 01 8b bf cc 00 00 00 44 0f 45 d0 45
> 31 c0 b8 aa 01 00 00 0f 05 <c3> 66 2e 0f 1f 84 00 00 00 00 00 41 83 e2
> 02 74 c2 f0 48 83 0c 24
> May 27 11:12:53 reproflushfull kernel: RSP: 002b:00007e8a67bfafd8
> EFLAGS: 00000246 ORIG_RAX: 00000000000001aa
> May 27 11:12:53 reproflushfull kernel: RAX: ffffffffffffffda RBX:
> 00007e8a580039f0 RCX: 00007e8a75069b95
> May 27 11:12:53 reproflushfull kernel: RDX: 0000000000000000 RSI:
> 0000000000000020 RDI: 0000000000000033
> May 27 11:12:53 reproflushfull kernel: RBP: 00007e8a580039f8 R08:
> 0000000000000000 R09: 0000000000000008
> May 27 11:12:53 reproflushfull kernel: R10: 0000000000000000 R11:
> 0000000000000246 R12: 00007e8a58003ae0
> May 27 11:12:53 reproflushfull kernel: R13: 0000000000000000 R14:
> 000064a145ca1c68 R15: 000064a183935450
> May 27 11:12:53 reproflushfull kernel:  </TASK>
> May 27 11:12:53 reproflushfull kernel: ---[ end trace 0000000000000000 ]---
>