last executing test programs:
kernel console output (not intermixed with test programs):
[ 66.216520][ T12] ------------[ cut here ]------------
[ 66.222090][ T12] WARNING: ./include/linux/backing-dev.h:243 at __folio_start_writeback+0x9d5/0xb70, CPU#0: kworker/u8:0/12
[ 66.233667][ T12] Modules linked in:
[ 66.237753][ T12] CPU: 0 UID: 0 PID: 12 Comm: kworker/u8:0 Not tainted syzkaller #0 PREEMPT(full)
[ 66.247326][ T12] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
[ 66.257459][ T12] Workqueue: writeback wb_workfn (flush-8:0)
[ 66.263571][ T12] RIP: 0010:__folio_start_writeback+0x9d5/0xb70
[ 66.269870][ T12] Code: 28 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 2e a2 29 00 49 8b 07 25 ff 3f 00 00 e9 1b fa ff ff e8 6c 04 c6 ff 90 <0f> 0b 90 e9 d6 fb ff ff e8 5e 04 c6 ff 48 c7 c7 20 fc 5f 8e 4c 89
[ 66.289526][ T12] RSP: 0018:ffffc90000116ea0 EFLAGS: 00010293
[ 66.295645][ T12] RAX: ffffffff81fadbd4 RBX: ffffea000091ddc0 RCX: ffff88801d2ada00
[ 66.303916][ T12] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 66.312256][ T12] RBP: ffffc90000117010 R08: ffffc90000116f97 R09: 0000000000000000
[ 66.320305][ T12] R10: ffffc90000116f80 R11: fffff52000022df3 R12: ffffea000091ddc8
[ 66.328332][ T12] R13: 0000000000000000 R14: ffff888148c6ab00 R15: ffff888148c6a8e0
[ 66.336342][ T12] FS: 0000000000000000(0000) GS:ffff8881257c0000(0000) knlGS:0000000000000000
[ 66.345286][ T12] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 66.351948][ T12] CR2: 000056252e1d6168 CR3: 000000007841c000 CR4: 00000000003526f0
[ 66.359964][ T12] Call Trace:
[ 66.363244][ T12]
[ 66.366256][ T12] ? folio_clear_dirty_for_io+0x226/0x880
[ 66.372092][ T12] ? __pfx___folio_start_writeback+0x10/0x10
[ 66.378124][ T12] ? __pfx_folio_clear_dirty_for_io+0x10/0x10
[ 66.384209][ T12] ? stack_trace_save+0x9c/0xe0
[ 66.389143][ T12] __block_write_full_folio+0x75f/0xe10
[ 66.394709][ T12] ? __pfx_blkdev_get_block+0x10/0x10
[ 66.400326][ T12] blkdev_writepages+0xd1/0x170
[ 66.405309][ T12] ? __pfx_blkdev_writepages+0x10/0x10
[ 66.410852][ T12] ? __pfx_blkdev_writepages+0x10/0x10
[ 66.416388][ T12] do_writepages+0x32b/0x550
[ 66.421172][ T12] __writeback_single_inode+0x145/0xff0
[ 66.426738][ T12] ? wbc_attach_and_unlock_inode+0x3f0/0x5d0
[ 66.433253][ T12] writeback_sb_inodes+0x6c7/0x1010
[ 66.438624][ T12] ? __pfx_writeback_sb_inodes+0x10/0x10
[ 66.444305][ T12] ? __pfx_down_read_trylock+0x10/0x10
[ 66.449801][ T12] ? __pfx___up_read+0x10/0x10
[ 66.454616][ T12] __writeback_inodes_wb+0x111/0x240
[ 66.460340][ T12] wb_writeback+0x44f/0xaf0
[ 66.464844][ T12] ? queue_io+0x381/0x590
[ 66.469250][ T12] ? __pfx_wb_writeback+0x10/0x10
[ 66.474385][ T12] wb_workfn+0xaef/0xef0
[ 66.478683][ T12] ? __pfx_wb_workfn+0x10/0x10
[ 66.483457][ T12] ? __lock_acquire+0xab9/0xd20
[ 66.488372][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 66.494203][ T12] ? _raw_spin_unlock_irq+0x23/0x50
[ 66.499465][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 66.505199][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 66.511493][ T12] process_scheduled_works+0xae1/0x17b0
[ 66.517132][ T12] ? __pfx_process_scheduled_works+0x10/0x10
[ 66.523233][ T12] worker_thread+0x8a0/0xda0
[ 66.527921][ T12] kthread+0x711/0x8a0
[ 66.532015][ T12] ? __pfx_worker_thread+0x10/0x10
[ 66.537174][ T12] ? __pfx_kthread+0x10/0x10
[ 66.542139][ T12] ? _raw_spin_unlock_irq+0x23/0x50
[ 66.547478][ T12] ? lockdep_hardirqs_on+0x9c/0x150
[ 66.552685][ T12] ? __pfx_kthread+0x10/0x10
[ 66.557313][ T12] ret_from_fork+0x47c/0x820
[ 66.561931][ T12] ? __pfx_ret_from_fork+0x10/0x10
[ 66.567083][ T12] ? __switch_to_asm+0x39/0x70
[ 66.571848][ T12] ? __switch_to_asm+0x33/0x70
[ 66.576742][ T12] ? __pfx_kthread+0x10/0x10
[ 66.581354][ T12] ret_from_fork_asm+0x1a/0x30
[ 66.586165][ T12]
[ 66.589185][ T12] Kernel panic - not syncing: kernel: panic_on_warn set ...
[ 66.596457][ T12] CPU: 0 UID: 0 PID: 12 Comm: kworker/u8:0 Not tainted syzkaller #0 PREEMPT(full)
[ 66.605714][ T12] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
[ 66.615751][ T12] Workqueue: writeback wb_workfn (flush-8:0)
[ 66.621742][ T12] Call Trace:
[ 66.625003][ T12]
[ 66.627914][ T12] dump_stack_lvl+0x99/0x250
[ 66.632487][ T12] ? __asan_memcpy+0x40/0x70
[ 66.637056][ T12] ? __pfx_dump_stack_lvl+0x10/0x10
[ 66.642235][ T12] ? __pfx__printk+0x10/0x10
[ 66.646824][ T12] vpanic+0x281/0x750
[ 66.650809][ T12] ? __pfx_vpanic+0x10/0x10
[ 66.655306][ T12] ? is_bpf_text_address+0x292/0x2b0
[ 66.660753][ T12] ? is_bpf_text_address+0x26/0x2b0
[ 66.665956][ T12] panic+0xb9/0xc0
[ 66.669684][ T12] ? __pfx_panic+0x10/0x10
[ 66.674106][ T12] ? ret_from_fork_asm+0x1a/0x30
[ 66.679055][ T12] __warn+0x334/0x4c0
[ 66.683047][ T12] ? __folio_start_writeback+0x9d5/0xb70
[ 66.688686][ T12] ? __folio_start_writeback+0x9d5/0xb70
[ 66.694311][ T12] report_bug+0x2be/0x4f0
[ 66.698647][ T12] ? __folio_start_writeback+0x9d5/0xb70
[ 66.704277][ T12] ? __folio_start_writeback+0x9d5/0xb70
[ 66.709922][ T12] ? __folio_start_writeback+0x9d7/0xb70
[ 66.715547][ T12] handle_bug+0x84/0x160
[ 66.719784][ T12] exc_invalid_op+0x1a/0x50
[ 66.724293][ T12] asm_exc_invalid_op+0x1a/0x20
[ 66.729215][ T12] RIP: 0010:__folio_start_writeback+0x9d5/0xb70
[ 66.735466][ T12] Code: 28 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 2e a2 29 00 49 8b 07 25 ff 3f 00 00 e9 1b fa ff ff e8 6c 04 c6 ff 90 <0f> 0b 90 e9 d6 fb ff ff e8 5e 04 c6 ff 48 c7 c7 20 fc 5f 8e 4c 89
[ 66.755509][ T12] RSP: 0018:ffffc90000116ea0 EFLAGS: 00010293
[ 66.761623][ T12] RAX: ffffffff81fadbd4 RBX: ffffea000091ddc0 RCX: ffff88801d2ada00
[ 66.769601][ T12] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 66.777563][ T12] RBP: ffffc90000117010 R08: ffffc90000116f97 R09: 0000000000000000
[ 66.785522][ T12] R10: ffffc90000116f80 R11: fffff52000022df3 R12: ffffea000091ddc8
[ 66.793483][ T12] R13: 0000000000000000 R14: ffff888148c6ab00 R15: ffff888148c6a8e0
[ 66.801800][ T12] ? __folio_start_writeback+0x9d4/0xb70
[ 66.807458][ T12] ? folio_clear_dirty_for_io+0x226/0x880
[ 66.813189][ T12] ? __pfx___folio_start_writeback+0x10/0x10
[ 66.819335][ T12] ? __pfx_folio_clear_dirty_for_io+0x10/0x10
[ 66.825570][ T12] ? stack_trace_save+0x9c/0xe0
[ 66.830427][ T12] __block_write_full_folio+0x75f/0xe10
[ 66.835979][ T12] ? __pfx_blkdev_get_block+0x10/0x10
[ 66.841468][ T12] blkdev_writepages+0xd1/0x170
[ 66.846318][ T12] ? __pfx_blkdev_writepages+0x10/0x10
[ 66.851785][ T12] ? __pfx_blkdev_writepages+0x10/0x10
[ 66.857244][ T12] do_writepages+0x32b/0x550
[ 66.861866][ T12] __writeback_single_inode+0x145/0xff0
[ 66.867411][ T12] ? wbc_attach_and_unlock_inode+0x3f0/0x5d0
[ 66.873398][ T12] writeback_sb_inodes+0x6c7/0x1010
[ 66.878608][ T12] ? __pfx_writeback_sb_inodes+0x10/0x10
[ 66.884274][ T12] ? __pfx_down_read_trylock+0x10/0x10
[ 66.889751][ T12] ? __pfx___up_read+0x10/0x10
[ 66.894567][ T12] __writeback_inodes_wb+0x111/0x240
[ 66.899859][ T12] wb_writeback+0x44f/0xaf0
[ 66.904456][ T12] ? queue_io+0x381/0x590
[ 66.908788][ T12] ? __pfx_wb_writeback+0x10/0x10
[ 66.913824][ T12] wb_workfn+0xaef/0xef0
[ 66.918088][ T12] ? __pfx_wb_workfn+0x10/0x10
[ 66.922852][ T12] ? __lock_acquire+0xab9/0xd20
[ 66.927703][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 66.933504][ T12] ? _raw_spin_unlock_irq+0x23/0x50
[ 66.938732][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 66.944557][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 66.950552][ T12] process_scheduled_works+0xae1/0x17b0
[ 66.956380][ T12] ? __pfx_process_scheduled_works+0x10/0x10
[ 66.962369][ T12] worker_thread+0x8a0/0xda0
[ 66.967079][ T12] kthread+0x711/0x8a0
[ 66.971147][ T12] ? __pfx_worker_thread+0x10/0x10
[ 66.976341][ T12] ? __pfx_kthread+0x10/0x10
[ 66.980938][ T12] ? _raw_spin_unlock_irq+0x23/0x50
[ 66.986130][ T12] ? lockdep_hardirqs_on+0x9c/0x150
[ 66.991364][ T12] ? __pfx_kthread+0x10/0x10
[ 66.995952][ T12] ret_from_fork+0x47c/0x820
[ 67.000737][ T12] ? __pfx_ret_from_fork+0x10/0x10
[ 67.005846][ T12] ? __switch_to_asm+0x39/0x70
[ 67.010686][ T12] ? __switch_to_asm+0x33/0x70
[ 67.015442][ T12] ? __pfx_kthread+0x10/0x10
[ 67.020026][ T12] ret_from_fork_asm+0x1a/0x30
[ 67.024796][ T12]
[ 67.028044][ T12] Kernel Offset: disabled
[ 67.032355][ T12] Rebooting in 86400 seconds..