last executing test programs:
kernel console output (not intermixed with test programs):
[ 65.267155][ T1168] ------------[ cut here ]------------
[ 65.272711][ T1168] WARNING: ./include/linux/backing-dev.h:243 at __folio_start_writeback+0x9d5/0xb70, CPU#1: kworker/u8:8/1168
[ 65.284452][ T1168] Modules linked in:
[ 65.288482][ T1168] CPU: 1 UID: 0 PID: 1168 Comm: kworker/u8:8 Not tainted syzkaller #0 PREEMPT(full)
[ 65.297994][ T1168] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
[ 65.308079][ T1168] Workqueue: writeback wb_workfn (flush-8:0)
[ 65.314074][ T1168] RIP: 0010:__folio_start_writeback+0x9d5/0xb70
[ 65.320434][ T1168] 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 3f 8e 4c 89
[ 65.340219][ T1168] RSP: 0018:ffffc90003e6eea0 EFLAGS: 00010293
[ 65.346374][ T1168] RAX: ffffffff81fa9bd4 RBX: ffffea000094a100 RCX: ffff8880276a0000
[ 65.354605][ T1168] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 65.362607][ T1168] RBP: ffffc90003e6f010 R08: ffffc90003e6ef97 R09: 0000000000000000
[ 65.370604][ T1168] R10: ffffc90003e6ef80 R11: fffff520007cddf3 R12: ffffea000094a108
[ 65.378599][ T1168] R13: 0000000000000000 R14: ffff88802306ab00 R15: ffff88802306a8e0
[ 65.386552][ T1168] FS: 0000000000000000(0000) GS:ffff888125afb000(0000) knlGS:0000000000000000
[ 65.395515][ T1168] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 65.402130][ T1168] CR2: 00005567ce896168 CR3: 0000000046c5c000 CR4: 00000000003526f0
[ 65.410573][ T1168] Call Trace:
[ 65.413857][ T1168]
[ 65.416811][ T1168] ? folio_clear_dirty_for_io+0x226/0x880
[ 65.422557][ T1168] ? __pfx___folio_start_writeback+0x10/0x10
[ 65.428585][ T1168] ? __pfx_folio_clear_dirty_for_io+0x10/0x10
[ 65.434662][ T1168] ? stack_trace_save+0x9c/0xe0
[ 65.439555][ T1168] __block_write_full_folio+0x75f/0xe10
[ 65.445103][ T1168] ? __pfx_blkdev_get_block+0x10/0x10
[ 65.450509][ T1168] blkdev_writepages+0xd1/0x170
[ 65.455387][ T1168] ? __pfx_blkdev_writepages+0x10/0x10
[ 65.460903][ T1168] ? __pfx_blkdev_writepages+0x10/0x10
[ 65.466369][ T1168] do_writepages+0x32b/0x550
[ 65.471001][ T1168] __writeback_single_inode+0x145/0xff0
[ 65.476593][ T1168] ? wbc_attach_and_unlock_inode+0x3f0/0x5d0
[ 65.482625][ T1168] writeback_sb_inodes+0x6c7/0x1010
[ 65.487910][ T1168] ? __pfx_writeback_sb_inodes+0x10/0x10
[ 65.493578][ T1168] ? __pfx_down_read_trylock+0x10/0x10
[ 65.499059][ T1168] ? __pfx___up_read+0x10/0x10
[ 65.503830][ T1168] __writeback_inodes_wb+0x111/0x240
[ 65.509411][ T1168] wb_writeback+0x44f/0xaf0
[ 65.513911][ T1168] ? queue_io+0x3b1/0x590
[ 65.518289][ T1168] ? __pfx_wb_writeback+0x10/0x10
[ 65.523338][ T1168] wb_workfn+0xaef/0xef0
[ 65.527638][ T1168] ? __pfx_wb_workfn+0x10/0x10
[ 65.532429][ T1168] ? __lock_acquire+0xab9/0xd20
[ 65.537342][ T1168] ? process_scheduled_works+0x9ef/0x17b0
[ 65.543094][ T1168] ? _raw_spin_unlock_irq+0x23/0x50
[ 65.548349][ T1168] ? process_scheduled_works+0x9ef/0x17b0
[ 65.554181][ T1168] ? process_scheduled_works+0x9ef/0x17b0
[ 65.559938][ T1168] process_scheduled_works+0xae1/0x17b0
[ 65.565516][ T1168] ? __pfx_process_scheduled_works+0x10/0x10
[ 65.571546][ T1168] worker_thread+0x8a0/0xda0
[ 65.576169][ T1168] ? __pfx__raw_spin_unlock_irqrestore+0x10/0x10
[ 65.582547][ T1168] ? __kthread_parkme+0x7b/0x200
[ 65.587536][ T1168] kthread+0x711/0x8a0
[ 65.591598][ T1168] ? __pfx_worker_thread+0x10/0x10
[ 65.596765][ T1168] ? __pfx_kthread+0x10/0x10
[ 65.601360][ T1168] ? _raw_spin_unlock_irq+0x23/0x50
[ 65.606544][ T1168] ? lockdep_hardirqs_on+0x9c/0x150
[ 65.611780][ T1168] ? __pfx_kthread+0x10/0x10
[ 65.616371][ T1168] ret_from_fork+0x47c/0x820
[ 65.621006][ T1168] ? __pfx_ret_from_fork+0x10/0x10
[ 65.626123][ T1168] ? __switch_to_asm+0x39/0x70
[ 65.630909][ T1168] ? __switch_to_asm+0x33/0x70
[ 65.635679][ T1168] ? __pfx_kthread+0x10/0x10
[ 65.640306][ T1168] ret_from_fork_asm+0x1a/0x30
[ 65.645083][ T1168]
[ 65.648240][ T1168] Kernel panic - not syncing: kernel: panic_on_warn set ...
[ 65.655514][ T1168] CPU: 1 UID: 0 PID: 1168 Comm: kworker/u8:8 Not tainted syzkaller #0 PREEMPT(full)
[ 65.664962][ T1168] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
[ 65.674996][ T1168] Workqueue: writeback wb_workfn (flush-8:0)
[ 65.680975][ T1168] Call Trace:
[ 65.684237][ T1168]
[ 65.687148][ T1168] dump_stack_lvl+0x99/0x250
[ 65.691735][ T1168] ? __asan_memcpy+0x40/0x70
[ 65.696330][ T1168] ? __pfx_dump_stack_lvl+0x10/0x10
[ 65.701509][ T1168] ? __pfx__printk+0x10/0x10
[ 65.706083][ T1168] vpanic+0x281/0x750
[ 65.710047][ T1168] ? __pfx_vpanic+0x10/0x10
[ 65.714544][ T1168] ? is_bpf_text_address+0x292/0x2b0
[ 65.719823][ T1168] ? is_bpf_text_address+0x26/0x2b0
[ 65.725021][ T1168] panic+0xb9/0xc0
[ 65.728733][ T1168] ? __pfx_panic+0x10/0x10
[ 65.733147][ T1168] ? ret_from_fork_asm+0x1a/0x30
[ 65.738083][ T1168] __warn+0x334/0x4c0
[ 65.742051][ T1168] ? __folio_start_writeback+0x9d5/0xb70
[ 65.747675][ T1168] ? __folio_start_writeback+0x9d5/0xb70
[ 65.753296][ T1168] report_bug+0x2be/0x4f0
[ 65.757617][ T1168] ? __folio_start_writeback+0x9d5/0xb70
[ 65.763242][ T1168] ? __folio_start_writeback+0x9d5/0xb70
[ 65.768864][ T1168] ? __folio_start_writeback+0x9d7/0xb70
[ 65.774487][ T1168] handle_bug+0x84/0x160
[ 65.778725][ T1168] exc_invalid_op+0x1a/0x50
[ 65.783221][ T1168] asm_exc_invalid_op+0x1a/0x20
[ 65.788058][ T1168] RIP: 0010:__folio_start_writeback+0x9d5/0xb70
[ 65.794291][ T1168] 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 3f 8e 4c 89
[ 65.813882][ T1168] RSP: 0018:ffffc90003e6eea0 EFLAGS: 00010293
[ 65.819941][ T1168] RAX: ffffffff81fa9bd4 RBX: ffffea000094a100 RCX: ffff8880276a0000
[ 65.827901][ T1168] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 65.835859][ T1168] RBP: ffffc90003e6f010 R08: ffffc90003e6ef97 R09: 0000000000000000
[ 65.843816][ T1168] R10: ffffc90003e6ef80 R11: fffff520007cddf3 R12: ffffea000094a108
[ 65.851782][ T1168] R13: 0000000000000000 R14: ffff88802306ab00 R15: ffff88802306a8e0
[ 65.859751][ T1168] ? __folio_start_writeback+0x9d4/0xb70
[ 65.865392][ T1168] ? folio_clear_dirty_for_io+0x226/0x880
[ 65.871109][ T1168] ? __pfx___folio_start_writeback+0x10/0x10
[ 65.877090][ T1168] ? __pfx_folio_clear_dirty_for_io+0x10/0x10
[ 65.883164][ T1168] ? stack_trace_save+0x9c/0xe0
[ 65.888019][ T1168] __block_write_full_folio+0x75f/0xe10
[ 65.893562][ T1168] ? __pfx_blkdev_get_block+0x10/0x10
[ 65.898938][ T1168] blkdev_writepages+0xd1/0x170
[ 65.903796][ T1168] ? __pfx_blkdev_writepages+0x10/0x10
[ 65.909278][ T1168] ? __pfx_blkdev_writepages+0x10/0x10
[ 65.914744][ T1168] do_writepages+0x32b/0x550
[ 65.919352][ T1168] __writeback_single_inode+0x145/0xff0
[ 65.924892][ T1168] ? wbc_attach_and_unlock_inode+0x3f0/0x5d0
[ 65.930873][ T1168] writeback_sb_inodes+0x6c7/0x1010
[ 65.936436][ T1168] ? __pfx_writeback_sb_inodes+0x10/0x10
[ 65.942096][ T1168] ? __pfx_down_read_trylock+0x10/0x10
[ 65.947638][ T1168] ? __pfx___up_read+0x10/0x10
[ 65.952402][ T1168] __writeback_inodes_wb+0x111/0x240
[ 65.957699][ T1168] wb_writeback+0x44f/0xaf0
[ 65.962219][ T1168] ? queue_io+0x3b1/0x590
[ 65.966546][ T1168] ? __pfx_wb_writeback+0x10/0x10
[ 65.971574][ T1168] wb_workfn+0xaef/0xef0
[ 65.975826][ T1168] ? __pfx_wb_workfn+0x10/0x10
[ 65.980590][ T1168] ? __lock_acquire+0xab9/0xd20
[ 65.985442][ T1168] ? process_scheduled_works+0x9ef/0x17b0
[ 65.991162][ T1168] ? _raw_spin_unlock_irq+0x23/0x50
[ 65.996354][ T1168] ? process_scheduled_works+0x9ef/0x17b0
[ 66.002154][ T1168] ? process_scheduled_works+0x9ef/0x17b0
[ 66.007870][ T1168] process_scheduled_works+0xae1/0x17b0
[ 66.013437][ T1168] ? __pfx_process_scheduled_works+0x10/0x10
[ 66.019433][ T1168] worker_thread+0x8a0/0xda0
[ 66.024023][ T1168] ? __pfx__raw_spin_unlock_irqrestore+0x10/0x10
[ 66.030386][ T1168] ? __kthread_parkme+0x7b/0x200
[ 66.035319][ T1168] kthread+0x711/0x8a0
[ 66.039387][ T1168] ? __pfx_worker_thread+0x10/0x10
[ 66.044578][ T1168] ? __pfx_kthread+0x10/0x10
[ 66.049159][ T1168] ? _raw_spin_unlock_irq+0x23/0x50
[ 66.054345][ T1168] ? lockdep_hardirqs_on+0x9c/0x150
[ 66.059535][ T1168] ? __pfx_kthread+0x10/0x10
[ 66.064123][ T1168] ret_from_fork+0x47c/0x820
[ 66.068711][ T1168] ? __pfx_ret_from_fork+0x10/0x10
[ 66.073824][ T1168] ? __switch_to_asm+0x39/0x70
[ 66.078583][ T1168] ? __switch_to_asm+0x33/0x70
[ 66.083345][ T1168] ? __pfx_kthread+0x10/0x10
[ 66.087929][ T1168] ret_from_fork_asm+0x1a/0x30
[ 66.092708][ T1168]
[ 66.095963][ T1168] Kernel Offset: disabled
[ 66.100282][ T1168] Rebooting in 86400 seconds..