last executing test programs:
kernel console output (not intermixed with test programs):
[ 66.078394][ T4339] ------------[ cut here ]------------
[ 66.083971][ T4339] WARNING: ./include/linux/backing-dev.h:243 at __folio_start_writeback+0x9d5/0xb70, CPU#1: kworker/u8:9/4339
[ 66.095717][ T4339] Modules linked in:
[ 66.099778][ T4339] CPU: 1 UID: 0 PID: 4339 Comm: kworker/u8:9 Not tainted syzkaller #0 PREEMPT(full)
[ 66.109289][ T4339] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
[ 66.119419][ T4339] Workqueue: writeback wb_workfn (flush-8:0)
[ 66.125414][ T4339] RIP: 0010:__folio_start_writeback+0x9d5/0xb70
[ 66.131699][ T4339] Code: 28 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 0e 02 2a 00 49 8b 07 25 ff 3f 00 00 e9 1b fa ff ff e8 bc f7 c5 ff 90 <0f> 0b 90 e9 d6 fb ff ff e8 ae f7 c5 ff 48 c7 c7 e0 fe 5f 8e 4c 89
[ 66.151398][ T4339] RSP: 0018:ffffc9000e01eea0 EFLAGS: 00010293
[ 66.157475][ T4339] RAX: ffffffff81fb0b84 RBX: ffffea0000930e40 RCX: ffff8880329bbc00
[ 66.165509][ T4339] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 66.173544][ T4339] RBP: ffffc9000e01f010 R08: ffffc9000e01ef97 R09: 0000000000000000
[ 66.181565][ T4339] R10: ffffc9000e01ef80 R11: fffff52001c03df3 R12: ffffea0000930e48
[ 66.189725][ T4339] R13: 0000000000000000 R14: ffff888023107000 R15: ffff888023106de0
[ 66.197693][ T4339] FS: 0000000000000000(0000) GS:ffff8881258ba000(0000) knlGS:0000000000000000
[ 66.206705][ T4339] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 66.213329][ T4339] CR2: 00005617b24f33f0 CR3: 0000000030ed6000 CR4: 00000000003526f0
[ 66.221766][ T4339] Call Trace:
[ 66.225055][ T4339]
[ 66.228049][ T4339] ? folio_clear_dirty_for_io+0x226/0x880
[ 66.233788][ T4339] ? __pfx___folio_start_writeback+0x10/0x10
[ 66.239814][ T4339] ? __pfx_folio_clear_dirty_for_io+0x10/0x10
[ 66.245889][ T4339] ? stack_trace_save+0x9c/0xe0
[ 66.250855][ T4339] __block_write_full_folio+0x75f/0xe10
[ 66.256497][ T4339] ? __pfx_blkdev_get_block+0x10/0x10
[ 66.262020][ T4339] blkdev_writepages+0xd1/0x170
[ 66.266880][ T4339] ? __pfx_blkdev_writepages+0x10/0x10
[ 66.272408][ T4339] ? __pfx_blkdev_writepages+0x10/0x10
[ 66.277924][ T4339] do_writepages+0x32e/0x550
[ 66.282532][ T4339] __writeback_single_inode+0x145/0xff0
[ 66.288139][ T4339] ? wbc_attach_and_unlock_inode+0x3f0/0x5d0
[ 66.294143][ T4339] writeback_sb_inodes+0x6c7/0x1010
[ 66.299434][ T4339] ? __pfx_writeback_sb_inodes+0x10/0x10
[ 66.305102][ T4339] ? __pfx_down_read_trylock+0x10/0x10
[ 66.310713][ T4339] ? __pfx___up_read+0x10/0x10
[ 66.315604][ T4339] __writeback_inodes_wb+0x111/0x240
[ 66.321056][ T4339] wb_writeback+0x44f/0xaf0
[ 66.325578][ T4339] ? queue_io+0x331/0x590
[ 66.330019][ T4339] ? __pfx_wb_writeback+0x10/0x10
[ 66.335057][ T4339] wb_workfn+0xaef/0xef0
[ 66.339649][ T4339] ? __pfx_wb_workfn+0x10/0x10
[ 66.344419][ T4339] ? __lock_acquire+0xab9/0xd20
[ 66.349376][ T4339] ? process_scheduled_works+0x9ef/0x17b0
[ 66.355111][ T4339] ? _raw_spin_unlock_irq+0x23/0x50
[ 66.360361][ T4339] ? process_scheduled_works+0x9ef/0x17b0
[ 66.366083][ T4339] ? process_scheduled_works+0x9ef/0x17b0
[ 66.371881][ T4339] process_scheduled_works+0xade/0x17b0
[ 66.377458][ T4339] ? __pfx_process_scheduled_works+0x10/0x10
[ 66.383525][ T4339] worker_thread+0x8a0/0xda0
[ 66.388215][ T4339] ? __pfx__raw_spin_unlock_irqrestore+0x10/0x10
[ 66.394545][ T4339] ? __kthread_parkme+0x7b/0x200
[ 66.399841][ T4339] kthread+0x70e/0x8a0
[ 66.403934][ T4339] ? __pfx_worker_thread+0x10/0x10
[ 66.409196][ T4339] ? __pfx_kthread+0x10/0x10
[ 66.413822][ T4339] ? _raw_spin_unlock_irq+0x23/0x50
[ 66.419060][ T4339] ? lockdep_hardirqs_on+0x9c/0x150
[ 66.424261][ T4339] ? __pfx_kthread+0x10/0x10
[ 66.428937][ T4339] ret_from_fork+0x47c/0x820
[ 66.433548][ T4339] ? __pfx_ret_from_fork+0x10/0x10
[ 66.438743][ T4339] ? __switch_to_asm+0x39/0x70
[ 66.443536][ T4339] ? __switch_to_asm+0x33/0x70
[ 66.448384][ T4339] ? __pfx_kthread+0x10/0x10
[ 66.452989][ T4339] ret_from_fork_asm+0x1a/0x30
[ 66.457754][ T4339]
[ 66.460826][ T4339] Kernel panic - not syncing: kernel: panic_on_warn set ...
[ 66.468101][ T4339] CPU: 1 UID: 0 PID: 4339 Comm: kworker/u8:9 Not tainted syzkaller #0 PREEMPT(full)
[ 66.477544][ T4339] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
[ 66.487780][ T4339] Workqueue: writeback wb_workfn (flush-8:0)
[ 66.493757][ T4339] Call Trace:
[ 66.497020][ T4339]
[ 66.499933][ T4339] dump_stack_lvl+0x99/0x250
[ 66.504518][ T4339] ? __asan_memcpy+0x40/0x70
[ 66.509094][ T4339] ? __pfx_dump_stack_lvl+0x10/0x10
[ 66.514276][ T4339] ? __pfx__printk+0x10/0x10
[ 66.518865][ T4339] vpanic+0x229/0x6d0
[ 66.522852][ T4339] ? __pfx_vpanic+0x10/0x10
[ 66.527346][ T4339] ? is_bpf_text_address+0x292/0x2b0
[ 66.532639][ T4339] ? is_bpf_text_address+0x26/0x2b0
[ 66.537838][ T4339] panic+0xb9/0xc0
[ 66.541560][ T4339] ? __pfx_panic+0x10/0x10
[ 66.545976][ T4339] ? ret_from_fork_asm+0x1a/0x30
[ 66.550909][ T4339] __warn+0x334/0x4c0
[ 66.554885][ T4339] ? __folio_start_writeback+0x9d5/0xb70
[ 66.560511][ T4339] ? __folio_start_writeback+0x9d5/0xb70
[ 66.566140][ T4339] report_bug+0x2be/0x4f0
[ 66.570463][ T4339] ? __folio_start_writeback+0x9d5/0xb70
[ 66.576085][ T4339] ? __folio_start_writeback+0x9d5/0xb70
[ 66.581747][ T4339] ? __folio_start_writeback+0x9d7/0xb70
[ 66.587368][ T4339] handle_bug+0x84/0x160
[ 66.591608][ T4339] exc_invalid_op+0x1a/0x50
[ 66.596110][ T4339] asm_exc_invalid_op+0x1a/0x20
[ 66.600952][ T4339] RIP: 0010:__folio_start_writeback+0x9d5/0xb70
[ 66.607222][ T4339] Code: 28 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 0e 02 2a 00 49 8b 07 25 ff 3f 00 00 e9 1b fa ff ff e8 bc f7 c5 ff 90 <0f> 0b 90 e9 d6 fb ff ff e8 ae f7 c5 ff 48 c7 c7 e0 fe 5f 8e 4c 89
[ 66.626818][ T4339] RSP: 0018:ffffc9000e01eea0 EFLAGS: 00010293
[ 66.632877][ T4339] RAX: ffffffff81fb0b84 RBX: ffffea0000930e40 RCX: ffff8880329bbc00
[ 66.640841][ T4339] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 66.648808][ T4339] RBP: ffffc9000e01f010 R08: ffffc9000e01ef97 R09: 0000000000000000
[ 66.656769][ T4339] R10: ffffc9000e01ef80 R11: fffff52001c03df3 R12: ffffea0000930e48
[ 66.664729][ T4339] R13: 0000000000000000 R14: ffff888023107000 R15: ffff888023106de0
[ 66.672728][ T4339] ? __folio_start_writeback+0x9d4/0xb70
[ 66.678365][ T4339] ? folio_clear_dirty_for_io+0x226/0x880
[ 66.684082][ T4339] ? __pfx___folio_start_writeback+0x10/0x10
[ 66.690058][ T4339] ? __pfx_folio_clear_dirty_for_io+0x10/0x10
[ 66.696120][ T4339] ? stack_trace_save+0x9c/0xe0
[ 66.700975][ T4339] __block_write_full_folio+0x75f/0xe10
[ 66.706534][ T4339] ? __pfx_blkdev_get_block+0x10/0x10
[ 66.711922][ T4339] blkdev_writepages+0xd1/0x170
[ 66.716786][ T4339] ? __pfx_blkdev_writepages+0x10/0x10
[ 66.722269][ T4339] ? __pfx_blkdev_writepages+0x10/0x10
[ 66.727726][ T4339] do_writepages+0x32e/0x550
[ 66.732325][ T4339] __writeback_single_inode+0x145/0xff0
[ 66.737869][ T4339] ? wbc_attach_and_unlock_inode+0x3f0/0x5d0
[ 66.743860][ T4339] writeback_sb_inodes+0x6c7/0x1010
[ 66.749074][ T4339] ? __pfx_writeback_sb_inodes+0x10/0x10
[ 66.754738][ T4339] ? __pfx_down_read_trylock+0x10/0x10
[ 66.760190][ T4339] ? __pfx___up_read+0x10/0x10
[ 66.764965][ T4339] __writeback_inodes_wb+0x111/0x240
[ 66.770252][ T4339] wb_writeback+0x44f/0xaf0
[ 66.774756][ T4339] ? queue_io+0x331/0x590
[ 66.779085][ T4339] ? __pfx_wb_writeback+0x10/0x10
[ 66.784116][ T4339] wb_workfn+0xaef/0xef0
[ 66.788369][ T4339] ? __pfx_wb_workfn+0x10/0x10
[ 66.793126][ T4339] ? __lock_acquire+0xab9/0xd20
[ 66.797989][ T4339] ? process_scheduled_works+0x9ef/0x17b0
[ 66.803736][ T4339] ? _raw_spin_unlock_irq+0x23/0x50
[ 66.808923][ T4339] ? process_scheduled_works+0x9ef/0x17b0
[ 66.814650][ T4339] ? process_scheduled_works+0x9ef/0x17b0
[ 66.820366][ T4339] process_scheduled_works+0xade/0x17b0
[ 66.825943][ T4339] ? __pfx_process_scheduled_works+0x10/0x10
[ 66.831946][ T4339] worker_thread+0x8a0/0xda0
[ 66.836542][ T4339] ? __pfx__raw_spin_unlock_irqrestore+0x10/0x10
[ 66.842867][ T4339] ? __kthread_parkme+0x7b/0x200
[ 66.847816][ T4339] kthread+0x70e/0x8a0
[ 66.851887][ T4339] ? __pfx_worker_thread+0x10/0x10
[ 66.856995][ T4339] ? __pfx_kthread+0x10/0x10
[ 66.861594][ T4339] ? _raw_spin_unlock_irq+0x23/0x50
[ 66.866874][ T4339] ? lockdep_hardirqs_on+0x9c/0x150
[ 66.872062][ T4339] ? __pfx_kthread+0x10/0x10
[ 66.876651][ T4339] ret_from_fork+0x47c/0x820
[ 66.881232][ T4339] ? __pfx_ret_from_fork+0x10/0x10
[ 66.886343][ T4339] ? __switch_to_asm+0x39/0x70
[ 66.891097][ T4339] ? __switch_to_asm+0x33/0x70
[ 66.895847][ T4339] ? __pfx_kthread+0x10/0x10
[ 66.900437][ T4339] ret_from_fork_asm+0x1a/0x30
[ 66.905206][ T4339]
[ 66.908473][ T4339] Kernel Offset: disabled
[ 66.912791][ T4339] Rebooting in 86400 seconds..