last executing test programs:
kernel console output (not intermixed with test programs):
[ 65.135083][ T12] ------------[ cut here ]------------
[ 65.140634][ T12] WARNING: ./include/linux/backing-dev.h:243 at __folio_start_writeback+0x9d5/0xb70, CPU#1: kworker/u8:0/12
[ 65.152197][ T12] Modules linked in:
[ 65.156221][ T12] CPU: 1 UID: 0 PID: 12 Comm: kworker/u8:0 Not tainted syzkaller #0 PREEMPT(full)
[ 65.165548][ T12] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
[ 65.175655][ T12] Workqueue: writeback wb_workfn (flush-8:0)
[ 65.181643][ T12] RIP: 0010:__folio_start_writeback+0x9d5/0xb70
[ 65.187912][ T12] Code: 28 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 ce a2 29 00 49 8b 07 25 ff 3f 00 00 e9 1b fa ff ff e8 7c 04 c6 ff 90 <0f> 0b 90 e9 d6 fb ff ff e8 6e 04 c6 ff 48 c7 c7 a0 f8 3f 8e 4c 89
[ 65.207604][ T12] RSP: 0018:ffffc90000116ea0 EFLAGS: 00010293
[ 65.213674][ T12] RAX: ffffffff81fa9344 RBX: ffffea0000935b80 RCX: ffff88801d295a00
[ 65.221697][ T12] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 65.229711][ T12] RBP: ffffc90000117010 R08: ffffc90000116f97 R09: 0000000000000000
[ 65.237702][ T12] R10: ffffc90000116f80 R11: fffff52000022df3 R12: ffffea0000935b88
[ 65.245724][ T12] R13: 0000000000000000 R14: ffff888025d38880 R15: ffff888025d38660
[ 65.253692][ T12] FS: 0000000000000000(0000) GS:ffff888125afe000(0000) knlGS:0000000000000000
[ 65.263126][ T12] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 65.269810][ T12] CR2: 0000565138525660 CR3: 000000005d4f6000 CR4: 00000000003526f0
[ 65.277831][ T12] Call Trace:
[ 65.281115][ T12]
[ 65.284136][ T12] ? folio_clear_dirty_for_io+0x226/0x880
[ 65.289924][ T12] ? __pfx___folio_start_writeback+0x10/0x10
[ 65.296123][ T12] ? __pfx_folio_clear_dirty_for_io+0x10/0x10
[ 65.302203][ T12] ? stack_trace_save+0x9c/0xe0
[ 65.307272][ T12] __block_write_full_folio+0x75f/0xe10
[ 65.312831][ T12] ? __pfx_blkdev_get_block+0x10/0x10
[ 65.318243][ T12] blkdev_writepages+0xd1/0x170
[ 65.323124][ T12] ? __pfx_blkdev_writepages+0x10/0x10
[ 65.328762][ T12] ? __pfx_blkdev_writepages+0x10/0x10
[ 65.334252][ T12] do_writepages+0x32e/0x550
[ 65.338910][ T12] __writeback_single_inode+0x145/0xff0
[ 65.344517][ T12] ? wbc_attach_and_unlock_inode+0x3f0/0x5d0
[ 65.350502][ T12] writeback_sb_inodes+0x6c7/0x1010
[ 65.355763][ T12] ? __pfx_writeback_sb_inodes+0x10/0x10
[ 65.361441][ T12] ? __pfx_down_read_trylock+0x10/0x10
[ 65.366957][ T12] ? __pfx___up_read+0x10/0x10
[ 65.371752][ T12] __writeback_inodes_wb+0x111/0x240
[ 65.377116][ T12] wb_writeback+0x44f/0xaf0
[ 65.381633][ T12] ? queue_io+0x381/0x590
[ 65.386020][ T12] ? __pfx_wb_writeback+0x10/0x10
[ 65.391057][ T12] wb_workfn+0xaef/0xef0
[ 65.395383][ T12] ? __pfx_wb_workfn+0x10/0x10
[ 65.400185][ T12] ? __lock_acquire+0xab9/0xd20
[ 65.405118][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 65.410861][ T12] ? _raw_spin_unlock_irq+0x23/0x50
[ 65.416167][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 65.421898][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 65.427694][ T12] process_scheduled_works+0xade/0x17b0
[ 65.433284][ T12] ? __pfx_process_scheduled_works+0x10/0x10
[ 65.439320][ T12] worker_thread+0x8a0/0xda0
[ 65.443942][ T12] kthread+0x711/0x8a0
[ 65.448094][ T12] ? __pfx_worker_thread+0x10/0x10
[ 65.453300][ T12] ? __pfx_kthread+0x10/0x10
[ 65.457922][ T12] ? _raw_spin_unlock_irq+0x23/0x50
[ 65.463122][ T12] ? lockdep_hardirqs_on+0x9c/0x150
[ 65.468396][ T12] ? __pfx_kthread+0x10/0x10
[ 65.473079][ T12] ret_from_fork+0x47c/0x820
[ 65.477706][ T12] ? __pfx_ret_from_fork+0x10/0x10
[ 65.482891][ T12] ? __switch_to_asm+0x39/0x70
[ 65.487756][ T12] ? __switch_to_asm+0x33/0x70
[ 65.492536][ T12] ? __pfx_kthread+0x10/0x10
[ 65.497188][ T12] ret_from_fork_asm+0x1a/0x30
[ 65.501977][ T12]
[ 65.505064][ T12] Kernel panic - not syncing: kernel: panic_on_warn set ...
[ 65.512349][ T12] CPU: 1 UID: 0 PID: 12 Comm: kworker/u8:0 Not tainted syzkaller #0 PREEMPT(full)
[ 65.521611][ T12] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
[ 65.531660][ T12] Workqueue: writeback wb_workfn (flush-8:0)
[ 65.537646][ T12] Call Trace:
[ 65.540910][ T12]
[ 65.543833][ T12] dump_stack_lvl+0x99/0x250
[ 65.548440][ T12] ? __asan_memcpy+0x40/0x70
[ 65.553014][ T12] ? __pfx_dump_stack_lvl+0x10/0x10
[ 65.558198][ T12] ? __pfx__printk+0x10/0x10
[ 65.562780][ T12] vpanic+0x281/0x750
[ 65.566751][ T12] ? __pfx_vpanic+0x10/0x10
[ 65.571249][ T12] ? is_bpf_text_address+0x292/0x2b0
[ 65.576525][ T12] ? is_bpf_text_address+0x26/0x2b0
[ 65.581720][ T12] panic+0xb9/0xc0
[ 65.585433][ T12] ? __pfx_panic+0x10/0x10
[ 65.589848][ T12] ? ret_from_fork_asm+0x1a/0x30
[ 65.594780][ T12] __warn+0x334/0x4c0
[ 65.598753][ T12] ? __folio_start_writeback+0x9d5/0xb70
[ 65.604380][ T12] ? __folio_start_writeback+0x9d5/0xb70
[ 65.610012][ T12] report_bug+0x2be/0x4f0
[ 65.614331][ T12] ? __folio_start_writeback+0x9d5/0xb70
[ 65.619954][ T12] ? __folio_start_writeback+0x9d5/0xb70
[ 65.625599][ T12] ? __folio_start_writeback+0x9d7/0xb70
[ 65.631220][ T12] handle_bug+0x84/0x160
[ 65.635455][ T12] exc_invalid_op+0x1a/0x50
[ 65.639948][ T12] asm_exc_invalid_op+0x1a/0x20
[ 65.644784][ T12] RIP: 0010:__folio_start_writeback+0x9d5/0xb70
[ 65.651015][ T12] Code: 28 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 ce a2 29 00 49 8b 07 25 ff 3f 00 00 e9 1b fa ff ff e8 7c 04 c6 ff 90 <0f> 0b 90 e9 d6 fb ff ff e8 6e 04 c6 ff 48 c7 c7 a0 f8 3f 8e 4c 89
[ 65.670614][ T12] RSP: 0018:ffffc90000116ea0 EFLAGS: 00010293
[ 65.676681][ T12] RAX: ffffffff81fa9344 RBX: ffffea0000935b80 RCX: ffff88801d295a00
[ 65.684641][ T12] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 65.692685][ T12] RBP: ffffc90000117010 R08: ffffc90000116f97 R09: 0000000000000000
[ 65.700645][ T12] R10: ffffc90000116f80 R11: fffff52000022df3 R12: ffffea0000935b88
[ 65.708602][ T12] R13: 0000000000000000 R14: ffff888025d38880 R15: ffff888025d38660
[ 65.716576][ T12] ? __folio_start_writeback+0x9d4/0xb70
[ 65.722299][ T12] ? folio_clear_dirty_for_io+0x226/0x880
[ 65.728017][ T12] ? __pfx___folio_start_writeback+0x10/0x10
[ 65.733993][ T12] ? __pfx_folio_clear_dirty_for_io+0x10/0x10
[ 65.740053][ T12] ? stack_trace_save+0x9c/0xe0
[ 65.744898][ T12] __block_write_full_folio+0x75f/0xe10
[ 65.750440][ T12] ? __pfx_blkdev_get_block+0x10/0x10
[ 65.755812][ T12] blkdev_writepages+0xd1/0x170
[ 65.760656][ T12] ? __pfx_blkdev_writepages+0x10/0x10
[ 65.766132][ T12] ? __pfx_blkdev_writepages+0x10/0x10
[ 65.771588][ T12] do_writepages+0x32e/0x550
[ 65.776191][ T12] __writeback_single_inode+0x145/0xff0
[ 65.781729][ T12] ? wbc_attach_and_unlock_inode+0x3f0/0x5d0
[ 65.787709][ T12] writeback_sb_inodes+0x6c7/0x1010
[ 65.792916][ T12] ? __pfx_writeback_sb_inodes+0x10/0x10
[ 65.798569][ T12] ? __pfx_down_read_trylock+0x10/0x10
[ 65.804100][ T12] ? __pfx___up_read+0x10/0x10
[ 65.808863][ T12] __writeback_inodes_wb+0x111/0x240
[ 65.814143][ T12] wb_writeback+0x44f/0xaf0
[ 65.818645][ T12] ? queue_io+0x381/0x590
[ 65.822979][ T12] ? __pfx_wb_writeback+0x10/0x10
[ 65.828003][ T12] wb_workfn+0xaef/0xef0
[ 65.832261][ T12] ? __pfx_wb_workfn+0x10/0x10
[ 65.837022][ T12] ? __lock_acquire+0xab9/0xd20
[ 65.841874][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 65.847589][ T12] ? _raw_spin_unlock_irq+0x23/0x50
[ 65.852870][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 65.858600][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 65.864312][ T12] process_scheduled_works+0xade/0x17b0
[ 65.869872][ T12] ? __pfx_process_scheduled_works+0x10/0x10
[ 65.875874][ T12] worker_thread+0x8a0/0xda0
[ 65.880502][ T12] kthread+0x711/0x8a0
[ 65.884579][ T12] ? __pfx_worker_thread+0x10/0x10
[ 65.889692][ T12] ? __pfx_kthread+0x10/0x10
[ 65.894279][ T12] ? _raw_spin_unlock_irq+0x23/0x50
[ 65.899469][ T12] ? lockdep_hardirqs_on+0x9c/0x150
[ 65.904752][ T12] ? __pfx_kthread+0x10/0x10
[ 65.909344][ T12] ret_from_fork+0x47c/0x820
[ 65.913941][ T12] ? __pfx_ret_from_fork+0x10/0x10
[ 65.919067][ T12] ? __switch_to_asm+0x39/0x70
[ 65.923828][ T12] ? __switch_to_asm+0x33/0x70
[ 65.928587][ T12] ? __pfx_kthread+0x10/0x10
[ 65.933168][ T12] ret_from_fork_asm+0x1a/0x30
[ 65.937943][ T12]
[ 65.941245][ T12] Kernel Offset: disabled
[ 65.945567][ T12] Rebooting in 86400 seconds..