last executing test programs:
kernel console output (not intermixed with test programs):
[ 66.508395][ T36] ------------[ cut here ]------------
[ 66.513972][ T36] WARNING: ./include/linux/backing-dev.h:243 at __folio_start_writeback+0x8e7/0xa50, CPU#1: kworker/u8:2/36
[ 66.525566][ T36] Modules linked in:
[ 66.529754][ T36] CPU: 1 UID: 0 PID: 36 Comm: kworker/u8:2 Not tainted syzkaller #0 PREEMPT(full)
[ 66.539207][ T36] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
[ 66.549351][ T36] Workqueue: writeback wb_workfn (flush-8:0)
[ 66.555453][ T36] RIP: 0010:__folio_start_writeback+0x8e7/0xa50
[ 66.561851][ T36] Code: 8b 05 bd 2f eb 10 48 3b 84 24 20 01 00 00 75 3b 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc e8 ca f6 c5 ff 90 <0f> 0b 90 e9 e5 fb ff ff e8 bc f6 c5 ff 48 c7 c7 a0 03 60 8e 4c 89
[ 66.581965][ T36] RSP: 0018:ffffc90000ac6ea0 EFLAGS: 00010293
[ 66.588080][ T36] RAX: ffffffff81fb1086 RBX: ffffea000508fc00 RCX: ffff8881432a1e00
[ 66.596140][ T36] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 66.604171][ T36] RBP: ffffc90000ac7010 R08: ffffc90000ac6f97 R09: 0000000000000000
[ 66.612268][ T36] R10: ffffc90000ac6f80 R11: fffff52000158df3 R12: ffffea000508fc08
[ 66.620365][ T36] R13: 0000000000000000 R14: ffff888025cccd80 R15: ffff888025cccb60
[ 66.628403][ T36] FS: 0000000000000000(0000) GS:ffff8881258bc000(0000) knlGS:0000000000000000
[ 66.637337][ T36] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 66.644062][ T36] CR2: 000055d804d1e660 CR3: 000000003338c000 CR4: 00000000003526f0
[ 66.652075][ T36] Call Trace:
[ 66.655363][ T36]
[ 66.658369][ T36] ? __pfx___folio_start_writeback+0x10/0x10
[ 66.664367][ T36] ? __pfx_folio_clear_dirty_for_io+0x10/0x10
[ 66.670688][ T36] ? stack_trace_save+0x9c/0xe0
[ 66.675649][ T36] __block_write_full_folio+0x75f/0xe10
[ 66.681274][ T36] ? __pfx_blkdev_get_block+0x10/0x10
[ 66.686652][ T36] blkdev_writepages+0xd1/0x170
[ 66.691552][ T36] ? __pfx_blkdev_writepages+0x10/0x10
[ 66.697146][ T36] ? irqentry_exit+0x74/0x90
[ 66.701993][ T36] ? __pfx_blkdev_writepages+0x10/0x10
[ 66.707474][ T36] do_writepages+0x32b/0x550
[ 66.712184][ T36] __writeback_single_inode+0x145/0xff0
[ 66.717824][ T36] ? wbc_attach_and_unlock_inode+0x3f0/0x5d0
[ 66.724030][ T36] writeback_sb_inodes+0x6c7/0x1010
[ 66.729353][ T36] ? __pfx_writeback_sb_inodes+0x10/0x10
[ 66.735181][ T36] ? __pfx_down_read_trylock+0x10/0x10
[ 66.740727][ T36] ? __pfx___up_read+0x10/0x10
[ 66.745779][ T36] __writeback_inodes_wb+0x111/0x240
[ 66.751279][ T36] wb_writeback+0x44f/0xaf0
[ 66.755827][ T36] ? queue_io+0x3d1/0x590
[ 66.760300][ T36] ? __pfx_wb_writeback+0x10/0x10
[ 66.765433][ T36] wb_workfn+0xaef/0xef0
[ 66.769774][ T36] ? __pfx_wb_workfn+0x10/0x10
[ 66.774644][ T36] ? __lock_acquire+0xab9/0xd20
[ 66.779727][ T36] ? process_scheduled_works+0x9ef/0x17b0
[ 66.785475][ T36] ? _raw_spin_unlock_irq+0x23/0x50
[ 66.790730][ T36] ? process_scheduled_works+0x9ef/0x17b0
[ 66.796473][ T36] ? process_scheduled_works+0x9ef/0x17b0
[ 66.802346][ T36] process_scheduled_works+0xade/0x17b0
[ 66.807983][ T36] ? __pfx_process_scheduled_works+0x10/0x10
[ 66.813965][ T36] worker_thread+0x8a0/0xda0
[ 66.818604][ T36] ? __kthread_parkme+0x7b/0x200
[ 66.823678][ T36] kthread+0x70e/0x8a0
[ 66.827812][ T36] ? __pfx_worker_thread+0x10/0x10
[ 66.832933][ T36] ? __pfx_kthread+0x10/0x10
[ 66.837511][ T36] ? _raw_spin_unlock_irq+0x23/0x50
[ 66.842768][ T36] ? lockdep_hardirqs_on+0x9c/0x150
[ 66.848000][ T36] ? __pfx_kthread+0x10/0x10
[ 66.852590][ T36] ret_from_fork+0x47c/0x820
[ 66.857259][ T36] ? __pfx_ret_from_fork+0x10/0x10
[ 66.862451][ T36] ? __switch_to_asm+0x39/0x70
[ 66.867215][ T36] ? __switch_to_asm+0x33/0x70
[ 66.872111][ T36] ? __pfx_kthread+0x10/0x10
[ 66.876704][ T36] ret_from_fork_asm+0x1a/0x30
[ 66.881547][ T36]
[ 66.884563][ T36] Kernel panic - not syncing: kernel: panic_on_warn set ...
[ 66.891848][ T36] CPU: 1 UID: 0 PID: 36 Comm: kworker/u8:2 Not tainted syzkaller #0 PREEMPT(full)
[ 66.901126][ T36] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
[ 66.911263][ T36] Workqueue: writeback wb_workfn (flush-8:0)
[ 66.917250][ T36] Call Trace:
[ 66.920519][ T36]
[ 66.923520][ T36] dump_stack_lvl+0x99/0x250
[ 66.928169][ T36] ? __asan_memcpy+0x40/0x70
[ 66.932762][ T36] ? __pfx_dump_stack_lvl+0x10/0x10
[ 66.938020][ T36] ? __pfx__printk+0x10/0x10
[ 66.942643][ T36] vpanic+0x229/0x6d0
[ 66.946627][ T36] ? __pfx_vpanic+0x10/0x10
[ 66.951197][ T36] ? is_bpf_text_address+0x292/0x2b0
[ 66.956479][ T36] ? is_bpf_text_address+0x26/0x2b0
[ 66.961757][ T36] panic+0xb9/0xc0
[ 66.965651][ T36] ? __pfx_panic+0x10/0x10
[ 66.970081][ T36] ? ret_from_fork_asm+0x1a/0x30
[ 66.975015][ T36] __warn+0x334/0x4c0
[ 66.978993][ T36] ? __folio_start_writeback+0x8e7/0xa50
[ 66.984619][ T36] ? __folio_start_writeback+0x8e7/0xa50
[ 66.990237][ T36] report_bug+0x2be/0x4f0
[ 66.994583][ T36] ? __folio_start_writeback+0x8e7/0xa50
[ 67.000225][ T36] ? __folio_start_writeback+0x8e7/0xa50
[ 67.005857][ T36] ? __folio_start_writeback+0x8e9/0xa50
[ 67.011478][ T36] handle_bug+0x84/0x160
[ 67.015716][ T36] exc_invalid_op+0x1a/0x50
[ 67.020215][ T36] asm_exc_invalid_op+0x1a/0x20
[ 67.025053][ T36] RIP: 0010:__folio_start_writeback+0x8e7/0xa50
[ 67.031280][ T36] Code: 8b 05 bd 2f eb 10 48 3b 84 24 20 01 00 00 75 3b 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc e8 ca f6 c5 ff 90 <0f> 0b 90 e9 e5 fb ff ff e8 bc f6 c5 ff 48 c7 c7 a0 03 60 8e 4c 89
[ 67.050974][ T36] RSP: 0018:ffffc90000ac6ea0 EFLAGS: 00010293
[ 67.057044][ T36] RAX: ffffffff81fb1086 RBX: ffffea000508fc00 RCX: ffff8881432a1e00
[ 67.065000][ T36] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 67.072965][ T36] RBP: ffffc90000ac7010 R08: ffffc90000ac6f97 R09: 0000000000000000
[ 67.080931][ T36] R10: ffffc90000ac6f80 R11: fffff52000158df3 R12: ffffea000508fc08
[ 67.088892][ T36] R13: 0000000000000000 R14: ffff888025cccd80 R15: ffff888025cccb60
[ 67.096857][ T36] ? __folio_start_writeback+0x8e6/0xa50
[ 67.102509][ T36] ? __pfx___folio_start_writeback+0x10/0x10
[ 67.108571][ T36] ? __pfx_folio_clear_dirty_for_io+0x10/0x10
[ 67.114633][ T36] ? stack_trace_save+0x9c/0xe0
[ 67.119577][ T36] __block_write_full_folio+0x75f/0xe10
[ 67.125219][ T36] ? __pfx_blkdev_get_block+0x10/0x10
[ 67.130860][ T36] blkdev_writepages+0xd1/0x170
[ 67.135706][ T36] ? __pfx_blkdev_writepages+0x10/0x10
[ 67.141174][ T36] ? irqentry_exit+0x74/0x90
[ 67.145759][ T36] ? __pfx_blkdev_writepages+0x10/0x10
[ 67.151293][ T36] do_writepages+0x32b/0x550
[ 67.155887][ T36] __writeback_single_inode+0x145/0xff0
[ 67.161424][ T36] ? wbc_attach_and_unlock_inode+0x3f0/0x5d0
[ 67.167625][ T36] writeback_sb_inodes+0x6c7/0x1010
[ 67.172941][ T36] ? __pfx_writeback_sb_inodes+0x10/0x10
[ 67.178594][ T36] ? __pfx_down_read_trylock+0x10/0x10
[ 67.184058][ T36] ? __pfx___up_read+0x10/0x10
[ 67.188826][ T36] __writeback_inodes_wb+0x111/0x240
[ 67.194198][ T36] wb_writeback+0x44f/0xaf0
[ 67.198807][ T36] ? queue_io+0x3d1/0x590
[ 67.203213][ T36] ? __pfx_wb_writeback+0x10/0x10
[ 67.208324][ T36] wb_workfn+0xaef/0xef0
[ 67.212566][ T36] ? __pfx_wb_workfn+0x10/0x10
[ 67.217410][ T36] ? __lock_acquire+0xab9/0xd20
[ 67.222431][ T36] ? process_scheduled_works+0x9ef/0x17b0
[ 67.228141][ T36] ? _raw_spin_unlock_irq+0x23/0x50
[ 67.233418][ T36] ? process_scheduled_works+0x9ef/0x17b0
[ 67.239324][ T36] ? process_scheduled_works+0x9ef/0x17b0
[ 67.245126][ T36] process_scheduled_works+0xade/0x17b0
[ 67.250772][ T36] ? __pfx_process_scheduled_works+0x10/0x10
[ 67.256777][ T36] worker_thread+0x8a0/0xda0
[ 67.261370][ T36] ? __kthread_parkme+0x7b/0x200
[ 67.266313][ T36] kthread+0x70e/0x8a0
[ 67.270479][ T36] ? __pfx_worker_thread+0x10/0x10
[ 67.275590][ T36] ? __pfx_kthread+0x10/0x10
[ 67.280196][ T36] ? _raw_spin_unlock_irq+0x23/0x50
[ 67.285402][ T36] ? lockdep_hardirqs_on+0x9c/0x150
[ 67.290675][ T36] ? __pfx_kthread+0x10/0x10
[ 67.295297][ T36] ret_from_fork+0x47c/0x820
[ 67.299886][ T36] ? __pfx_ret_from_fork+0x10/0x10
[ 67.304995][ T36] ? __switch_to_asm+0x39/0x70
[ 67.309750][ T36] ? __switch_to_asm+0x33/0x70
[ 67.314502][ T36] ? __pfx_kthread+0x10/0x10
[ 67.319119][ T36] ret_from_fork_asm+0x1a/0x30
[ 67.323883][ T36]
[ 67.327149][ T36] Kernel Offset: disabled
[ 67.331511][ T36] Rebooting in 86400 seconds..