last executing test programs:
kernel console output (not intermixed with test programs):
[ 65.907525][ T76] ------------[ cut here ]------------
[ 65.913136][ T76] WARNING: ./include/linux/backing-dev.h:243 at __folio_start_writeback+0x9d5/0xb70, CPU#1: kworker/u8:4/76
[ 65.924947][ T76] Modules linked in:
[ 65.929012][ T76] CPU: 1 UID: 0 PID: 76 Comm: kworker/u8:4 Not tainted syzkaller #0 PREEMPT(full)
[ 65.938367][ T76] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
[ 65.948574][ T76] Workqueue: writeback wb_workfn (flush-8:0)
[ 65.954585][ T76] RIP: 0010:__folio_start_writeback+0x9d5/0xb70
[ 65.960885][ T76] 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
[ 65.980629][ T76] RSP: 0018:ffffc9000218eea0 EFLAGS: 00010293
[ 65.986700][ T76] RAX: ffffffff81fa9bd4 RBX: ffffea00009311c0 RCX: ffff88801d348000
[ 65.994783][ T76] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 66.002809][ T76] RBP: ffffc9000218f010 R08: ffffc9000218ef97 R09: 0000000000000000
[ 66.010826][ T76] R10: ffffc9000218ef80 R11: fffff52000431df3 R12: ffffea00009311c8
[ 66.018866][ T76] R13: 0000000000000000 R14: ffff88802339ab00 R15: ffff88802339a8e0
[ 66.026840][ T76] FS: 0000000000000000(0000) GS:ffff888125afb000(0000) knlGS:0000000000000000
[ 66.035840][ T76] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 66.042475][ T76] CR2: 0000560b4c4bd168 CR3: 000000000e138000 CR4: 00000000003526f0
[ 66.050483][ T76] Call Trace:
[ 66.053769][ T76]
[ 66.056710][ T76] ? folio_clear_dirty_for_io+0x226/0x880
[ 66.062529][ T76] ? __pfx___folio_start_writeback+0x10/0x10
[ 66.068587][ T76] ? __pfx_folio_clear_dirty_for_io+0x10/0x10
[ 66.074675][ T76] ? stack_trace_save+0x9c/0xe0
[ 66.079619][ T76] __block_write_full_folio+0x75f/0xe10
[ 66.085194][ T76] ? __pfx_blkdev_get_block+0x10/0x10
[ 66.090625][ T76] blkdev_writepages+0xd1/0x170
[ 66.095482][ T76] ? __pfx_blkdev_writepages+0x10/0x10
[ 66.100993][ T76] ? __pfx_blkdev_writepages+0x10/0x10
[ 66.106481][ T76] do_writepages+0x32b/0x550
[ 66.111121][ T76] __writeback_single_inode+0x145/0xff0
[ 66.116667][ T76] ? wbc_attach_and_unlock_inode+0x3f0/0x5d0
[ 66.122681][ T76] writeback_sb_inodes+0x6c7/0x1010
[ 66.127920][ T76] ? __pfx_writeback_sb_inodes+0x10/0x10
[ 66.133565][ T76] ? __pfx_down_read_trylock+0x10/0x10
[ 66.139040][ T76] ? __pfx___up_read+0x10/0x10
[ 66.143814][ T76] __writeback_inodes_wb+0x111/0x240
[ 66.149231][ T76] wb_writeback+0x44f/0xaf0
[ 66.153740][ T76] ? queue_io+0x3b1/0x590
[ 66.158125][ T76] ? __pfx_wb_writeback+0x10/0x10
[ 66.163160][ T76] wb_workfn+0xaef/0xef0
[ 66.167454][ T76] ? __pfx_wb_workfn+0x10/0x10
[ 66.172225][ T76] ? __lock_acquire+0xab9/0xd20
[ 66.177109][ T76] ? process_scheduled_works+0x9ef/0x17b0
[ 66.182834][ T76] ? _raw_spin_unlock_irq+0x23/0x50
[ 66.188066][ T76] ? process_scheduled_works+0x9ef/0x17b0
[ 66.193791][ T76] ? process_scheduled_works+0x9ef/0x17b0
[ 66.199579][ T76] process_scheduled_works+0xae1/0x17b0
[ 66.205177][ T76] ? __pfx_process_scheduled_works+0x10/0x10
[ 66.211229][ T76] worker_thread+0x8a0/0xda0
[ 66.215869][ T76] kthread+0x711/0x8a0
[ 66.219990][ T76] ? __pfx_worker_thread+0x10/0x10
[ 66.225109][ T76] ? __pfx_kthread+0x10/0x10
[ 66.229723][ T76] ? _raw_spin_unlock_irq+0x23/0x50
[ 66.234976][ T76] ? lockdep_hardirqs_on+0x9c/0x150
[ 66.240200][ T76] ? __pfx_kthread+0x10/0x10
[ 66.244793][ T76] ret_from_fork+0x47c/0x820
[ 66.249413][ T76] ? __pfx_ret_from_fork+0x10/0x10
[ 66.254539][ T76] ? __switch_to_asm+0x39/0x70
[ 66.259344][ T76] ? __switch_to_asm+0x33/0x70
[ 66.264120][ T76] ? __pfx_kthread+0x10/0x10
[ 66.268759][ T76] ret_from_fork_asm+0x1a/0x30
[ 66.273566][ T76]
[ 66.276595][ T76] Kernel panic - not syncing: kernel: panic_on_warn set ...
[ 66.283870][ T76] CPU: 1 UID: 0 PID: 76 Comm: kworker/u8:4 Not tainted syzkaller #0 PREEMPT(full)
[ 66.293129][ T76] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
[ 66.303165][ T76] Workqueue: writeback wb_workfn (flush-8:0)
[ 66.309139][ T76] Call Trace:
[ 66.312400][ T76]
[ 66.315313][ T76] dump_stack_lvl+0x99/0x250
[ 66.319886][ T76] ? __asan_memcpy+0x40/0x70
[ 66.324582][ T76] ? __pfx_dump_stack_lvl+0x10/0x10
[ 66.329766][ T76] ? __pfx__printk+0x10/0x10
[ 66.334388][ T76] vpanic+0x281/0x750
[ 66.338384][ T76] ? __pfx_vpanic+0x10/0x10
[ 66.342896][ T76] ? is_bpf_text_address+0x292/0x2b0
[ 66.348199][ T76] ? is_bpf_text_address+0x26/0x2b0
[ 66.353406][ T76] panic+0xb9/0xc0
[ 66.357125][ T76] ? __pfx_panic+0x10/0x10
[ 66.362070][ T76] ? ret_from_fork_asm+0x1a/0x30
[ 66.367007][ T76] __warn+0x334/0x4c0
[ 66.370985][ T76] ? __folio_start_writeback+0x9d5/0xb70
[ 66.376611][ T76] ? __folio_start_writeback+0x9d5/0xb70
[ 66.382236][ T76] report_bug+0x2be/0x4f0
[ 66.386558][ T76] ? __folio_start_writeback+0x9d5/0xb70
[ 66.392190][ T76] ? __folio_start_writeback+0x9d5/0xb70
[ 66.397865][ T76] ? __folio_start_writeback+0x9d7/0xb70
[ 66.403491][ T76] handle_bug+0x84/0x160
[ 66.407734][ T76] exc_invalid_op+0x1a/0x50
[ 66.412231][ T76] asm_exc_invalid_op+0x1a/0x20
[ 66.417073][ T76] RIP: 0010:__folio_start_writeback+0x9d5/0xb70
[ 66.423391][ T76] 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
[ 66.443075][ T76] RSP: 0018:ffffc9000218eea0 EFLAGS: 00010293
[ 66.449134][ T76] RAX: ffffffff81fa9bd4 RBX: ffffea00009311c0 RCX: ffff88801d348000
[ 66.457096][ T76] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 66.465063][ T76] RBP: ffffc9000218f010 R08: ffffc9000218ef97 R09: 0000000000000000
[ 66.473037][ T76] R10: ffffc9000218ef80 R11: fffff52000431df3 R12: ffffea00009311c8
[ 66.481014][ T76] R13: 0000000000000000 R14: ffff88802339ab00 R15: ffff88802339a8e0
[ 66.488994][ T76] ? __folio_start_writeback+0x9d4/0xb70
[ 66.494666][ T76] ? folio_clear_dirty_for_io+0x226/0x880
[ 66.500400][ T76] ? __pfx___folio_start_writeback+0x10/0x10
[ 66.506395][ T76] ? __pfx_folio_clear_dirty_for_io+0x10/0x10
[ 66.512476][ T76] ? stack_trace_save+0x9c/0xe0
[ 66.517330][ T76] __block_write_full_folio+0x75f/0xe10
[ 66.522871][ T76] ? __pfx_blkdev_get_block+0x10/0x10
[ 66.528245][ T76] blkdev_writepages+0xd1/0x170
[ 66.533095][ T76] ? __pfx_blkdev_writepages+0x10/0x10
[ 66.538565][ T76] ? __pfx_blkdev_writepages+0x10/0x10
[ 66.544024][ T76] do_writepages+0x32b/0x550
[ 66.548633][ T76] __writeback_single_inode+0x145/0xff0
[ 66.554175][ T76] ? wbc_attach_and_unlock_inode+0x3f0/0x5d0
[ 66.560154][ T76] writeback_sb_inodes+0x6c7/0x1010
[ 66.565367][ T76] ? __pfx_writeback_sb_inodes+0x10/0x10
[ 66.571022][ T76] ? __pfx_down_read_trylock+0x10/0x10
[ 66.576478][ T76] ? __pfx___up_read+0x10/0x10
[ 66.581242][ T76] __writeback_inodes_wb+0x111/0x240
[ 66.586529][ T76] wb_writeback+0x44f/0xaf0
[ 66.591043][ T76] ? queue_io+0x3b1/0x590
[ 66.595388][ T76] ? __pfx_wb_writeback+0x10/0x10
[ 66.600436][ T76] wb_workfn+0xaef/0xef0
[ 66.604696][ T76] ? __pfx_wb_workfn+0x10/0x10
[ 66.609458][ T76] ? __lock_acquire+0xab9/0xd20
[ 66.614312][ T76] ? process_scheduled_works+0x9ef/0x17b0
[ 66.620031][ T76] ? _raw_spin_unlock_irq+0x23/0x50
[ 66.625221][ T76] ? process_scheduled_works+0x9ef/0x17b0
[ 66.630934][ T76] ? process_scheduled_works+0x9ef/0x17b0
[ 66.636740][ T76] process_scheduled_works+0xae1/0x17b0
[ 66.642312][ T76] ? __pfx_process_scheduled_works+0x10/0x10
[ 66.648300][ T76] worker_thread+0x8a0/0xda0
[ 66.652908][ T76] kthread+0x711/0x8a0
[ 66.656979][ T76] ? __pfx_worker_thread+0x10/0x10
[ 66.662083][ T76] ? __pfx_kthread+0x10/0x10
[ 66.666661][ T76] ? _raw_spin_unlock_irq+0x23/0x50
[ 66.671851][ T76] ? lockdep_hardirqs_on+0x9c/0x150
[ 66.677047][ T76] ? __pfx_kthread+0x10/0x10
[ 66.681627][ T76] ret_from_fork+0x47c/0x820
[ 66.686215][ T76] ? __pfx_ret_from_fork+0x10/0x10
[ 66.691330][ T76] ? __switch_to_asm+0x39/0x70
[ 66.696085][ T76] ? __switch_to_asm+0x33/0x70
[ 66.700844][ T76] ? __pfx_kthread+0x10/0x10
[ 66.705425][ T76] ret_from_fork_asm+0x1a/0x30
[ 66.710205][ T76]
[ 66.713454][ T76] Kernel Offset: disabled
[ 66.717785][ T76] Rebooting in 86400 seconds..