last executing test programs:
kernel console output (not intermixed with test programs):
[ 66.256893][ T60] ------------[ cut here ]------------
[ 66.262451][ T60] WARNING: ./include/linux/backing-dev.h:243 at __folio_start_writeback+0x8e7/0xa50, CPU#0: kworker/u8:4/60
[ 66.274067][ T60] Modules linked in:
[ 66.278383][ T60] CPU: 0 UID: 0 PID: 60 Comm: kworker/u8:4 Not tainted syzkaller #0 PREEMPT(full)
[ 66.287724][ T60] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
[ 66.297933][ T60] Workqueue: writeback wb_workfn (flush-8:0)
Warning: Permanently added '10.128.1.201' (ED25519) to the list of known hosts.
[ 66.303972][ T60] RIP: 0010:__folio_start_writeback+0x8e7/0xa50
[ 66.310301][ T60] Code: 8b 05 bd bf c7 10 48 3b 84 24 20 01 00 00 75 3b 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc e8 ca f6 c5 ff 90 <0f> 0b 90 e9 e5 fb ff ff e8 bc f6 c5 ff 48 c7 c7 a0 03 40 8e 4c 89
[ 66.330081][ T60] RSP: 0018:ffffc9000211eea0 EFLAGS: 00010293
[ 66.336154][ T60] RAX: ffffffff81fad086 RBX: ffffea00009428c0 RCX: ffff88801c3d8000
[ 66.344182][ T60] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 66.352201][ T60] RBP: ffffc9000211f010 R08: ffffc9000211ef97 R09: 0000000000000000
[ 66.360207][ T60] R10: ffffc9000211ef80 R11: fffff52000423df3 R12: ffffea00009428c8
[ 66.368210][ T60] R13: 0000000000000000 R14: ffff8880230e9f80 R15: ffff8880230e9d60
[ 66.376175][ T60] FS: 0000000000000000(0000) GS:ffff8881259f7000(0000) knlGS:0000000000000000
[ 66.385165][ T60] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 66.391794][ T60] CR2: 000055fbf95dc204 CR3: 000000000e138000 CR4: 00000000003526f0
[ 66.399825][ T60] Call Trace:
[ 66.403120][ T60]
[ 66.406073][ T60] ? __pfx___folio_start_writeback+0x10/0x10
[ 66.412144][ T60] ? __pfx_folio_clear_dirty_for_io+0x10/0x10
[ 66.418365][ T60] __block_write_full_folio+0x75f/0xe10
[ 66.423925][ T60] ? __pfx_blkdev_get_block+0x10/0x10
[ 66.429378][ T60] blkdev_writepages+0xd1/0x170
[ 66.434238][ T60] ? __pfx_blkdev_writepages+0x10/0x10
[ 66.439820][ T60] ? do_raw_spin_unlock+0x122/0x240
[ 66.445044][ T60] ? __pfx_blkdev_writepages+0x10/0x10
[ 66.450622][ T60] do_writepages+0x32b/0x550
[ 66.455231][ T60] __writeback_single_inode+0x145/0xff0
[ 66.460822][ T60] ? wbc_attach_and_unlock_inode+0x3f0/0x5d0
[ 66.466833][ T60] writeback_sb_inodes+0x6c7/0x1010
[ 66.472039][ T60] ? __pfx_writeback_sb_inodes+0x10/0x10
[ 66.477768][ T60] ? __pfx_down_read_trylock+0x10/0x10
[ 66.483504][ T60] ? __pfx_move_expired_inodes+0x10/0x10
[ 66.489201][ T60] __writeback_inodes_wb+0x111/0x240
[ 66.494499][ T60] wb_writeback+0x44f/0xaf0
[ 66.499066][ T60] ? queue_io+0x3d1/0x590
[ 66.503425][ T60] ? __pfx_wb_writeback+0x10/0x10
[ 66.508545][ T60] wb_workfn+0xaef/0xef0
[ 66.512826][ T60] ? __pfx_wb_workfn+0x10/0x10
[ 66.517688][ T60] ? __lock_acquire+0xab9/0xd20
[ 66.522745][ T60] ? process_scheduled_works+0x9ef/0x17b0
[ 66.528550][ T60] ? _raw_spin_unlock_irq+0x23/0x50
[ 66.533782][ T60] ? process_scheduled_works+0x9ef/0x17b0
[ 66.539615][ T60] ? process_scheduled_works+0x9ef/0x17b0
[ 66.545360][ T60] process_scheduled_works+0xade/0x17b0
[ 66.551033][ T60] ? __pfx_process_scheduled_works+0x10/0x10
[ 66.557178][ T60] worker_thread+0x8a0/0xda0
[ 66.561806][ T60] kthread+0x70e/0x8a0
[ 66.565886][ T60] ? __pfx_worker_thread+0x10/0x10
[ 66.571530][ T60] ? __pfx_kthread+0x10/0x10
[ 66.576149][ T60] ? _raw_spin_unlock_irq+0x23/0x50
[ 66.581597][ T60] ? lockdep_hardirqs_on+0x9c/0x150
[ 66.586833][ T60] ? __pfx_kthread+0x10/0x10
[ 66.591436][ T60] ret_from_fork+0x47c/0x820
[ 66.596041][ T60] ? __pfx_ret_from_fork+0x10/0x10
[ 66.601247][ T60] ? __switch_to_asm+0x39/0x70
[ 66.606019][ T60] ? __switch_to_asm+0x33/0x70
[ 66.610867][ T60] ? __pfx_kthread+0x10/0x10
[ 66.615470][ T60] ret_from_fork_asm+0x1a/0x30
[ 66.620313][ T60]
[ 66.623351][ T60] Kernel panic - not syncing: kernel: panic_on_warn set ...
[ 66.630718][ T60] CPU: 0 UID: 0 PID: 60 Comm: kworker/u8:4 Not tainted syzkaller #0 PREEMPT(full)
[ 66.639987][ T60] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
[ 66.650206][ T60] Workqueue: writeback wb_workfn (flush-8:0)
[ 66.656187][ T60] Call Trace:
[ 66.659459][ T60]
[ 66.662375][ T60] dump_stack_lvl+0x99/0x250
[ 66.666956][ T60] ? __asan_memcpy+0x40/0x70
[ 66.671532][ T60] ? __pfx_dump_stack_lvl+0x10/0x10
[ 66.676722][ T60] ? __pfx__printk+0x10/0x10
[ 66.681315][ T60] vpanic+0x229/0x6d0
[ 66.685367][ T60] ? __pfx_vpanic+0x10/0x10
[ 66.689855][ T60] ? is_bpf_text_address+0x292/0x2b0
[ 66.695127][ T60] ? is_bpf_text_address+0x26/0x2b0
[ 66.700404][ T60] panic+0xb9/0xc0
[ 66.704113][ T60] ? __pfx_panic+0x10/0x10
[ 66.708612][ T60] ? ret_from_fork_asm+0x1a/0x30
[ 66.713548][ T60] __warn+0x334/0x4c0
[ 66.717513][ T60] ? __folio_start_writeback+0x8e7/0xa50
[ 66.723141][ T60] ? __folio_start_writeback+0x8e7/0xa50
[ 66.728760][ T60] report_bug+0x2be/0x4f0
[ 66.733075][ T60] ? __folio_start_writeback+0x8e7/0xa50
[ 66.738693][ T60] ? __folio_start_writeback+0x8e7/0xa50
[ 66.744313][ T60] ? __folio_start_writeback+0x8e9/0xa50
[ 66.749932][ T60] handle_bug+0x84/0x160
[ 66.754162][ T60] exc_invalid_op+0x1a/0x50
[ 66.758654][ T60] asm_exc_invalid_op+0x1a/0x20
[ 66.763504][ T60] RIP: 0010:__folio_start_writeback+0x8e7/0xa50
[ 66.769738][ T60] Code: 8b 05 bd bf c7 10 48 3b 84 24 20 01 00 00 75 3b 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc e8 ca f6 c5 ff 90 <0f> 0b 90 e9 e5 fb ff ff e8 bc f6 c5 ff 48 c7 c7 a0 03 40 8e 4c 89
[ 66.789330][ T60] RSP: 0018:ffffc9000211eea0 EFLAGS: 00010293
[ 66.795387][ T60] RAX: ffffffff81fad086 RBX: ffffea00009428c0 RCX: ffff88801c3d8000
[ 66.803428][ T60] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 66.811394][ T60] RBP: ffffc9000211f010 R08: ffffc9000211ef97 R09: 0000000000000000
[ 66.819356][ T60] R10: ffffc9000211ef80 R11: fffff52000423df3 R12: ffffea00009428c8
[ 66.827397][ T60] R13: 0000000000000000 R14: ffff8880230e9f80 R15: ffff8880230e9d60
[ 66.835357][ T60] ? __folio_start_writeback+0x8e6/0xa50
[ 66.840995][ T60] ? __pfx___folio_start_writeback+0x10/0x10
[ 66.847050][ T60] ? __pfx_folio_clear_dirty_for_io+0x10/0x10
[ 66.853201][ T60] __block_write_full_folio+0x75f/0xe10
[ 66.858732][ T60] ? __pfx_blkdev_get_block+0x10/0x10
[ 66.864091][ T60] blkdev_writepages+0xd1/0x170
[ 66.868940][ T60] ? __pfx_blkdev_writepages+0x10/0x10
[ 66.874402][ T60] ? do_raw_spin_unlock+0x122/0x240
[ 66.879586][ T60] ? __pfx_blkdev_writepages+0x10/0x10
[ 66.885027][ T60] do_writepages+0x32b/0x550
[ 66.889617][ T60] __writeback_single_inode+0x145/0xff0
[ 66.895156][ T60] ? wbc_attach_and_unlock_inode+0x3f0/0x5d0
[ 66.901123][ T60] writeback_sb_inodes+0x6c7/0x1010
[ 66.906325][ T60] ? __pfx_writeback_sb_inodes+0x10/0x10
[ 66.911970][ T60] ? __pfx_down_read_trylock+0x10/0x10
[ 66.917503][ T60] ? __pfx_move_expired_inodes+0x10/0x10
[ 66.923132][ T60] __writeback_inodes_wb+0x111/0x240
[ 66.928425][ T60] wb_writeback+0x44f/0xaf0
[ 66.932918][ T60] ? queue_io+0x3d1/0x590
[ 66.937321][ T60] ? __pfx_wb_writeback+0x10/0x10
[ 66.942345][ T60] wb_workfn+0xaef/0xef0
[ 66.946580][ T60] ? __pfx_wb_workfn+0x10/0x10
[ 66.951327][ T60] ? __lock_acquire+0xab9/0xd20
[ 66.956174][ T60] ? process_scheduled_works+0x9ef/0x17b0
[ 66.961887][ T60] ? _raw_spin_unlock_irq+0x23/0x50
[ 66.967097][ T60] ? process_scheduled_works+0x9ef/0x17b0
[ 66.972890][ T60] ? process_scheduled_works+0x9ef/0x17b0
[ 66.978597][ T60] process_scheduled_works+0xade/0x17b0
[ 66.984153][ T60] ? __pfx_process_scheduled_works+0x10/0x10
[ 66.990144][ T60] worker_thread+0x8a0/0xda0
[ 66.994734][ T60] kthread+0x70e/0x8a0
[ 66.998791][ T60] ? __pfx_worker_thread+0x10/0x10
[ 67.003984][ T60] ? __pfx_kthread+0x10/0x10
[ 67.008557][ T60] ? _raw_spin_unlock_irq+0x23/0x50
[ 67.013737][ T60] ? lockdep_hardirqs_on+0x9c/0x150
[ 67.018917][ T60] ? __pfx_kthread+0x10/0x10
[ 67.023491][ T60] ret_from_fork+0x47c/0x820
[ 67.028078][ T60] ? __pfx_ret_from_fork+0x10/0x10
[ 67.033190][ T60] ? __switch_to_asm+0x39/0x70
[ 67.037939][ T60] ? __switch_to_asm+0x33/0x70
[ 67.042689][ T60] ? __pfx_kthread+0x10/0x10
[ 67.047265][ T60] ret_from_fork_asm+0x1a/0x30
[ 67.052032][ T60]
[ 67.055313][ T60] Kernel Offset: disabled
[ 67.059654][ T60] Rebooting in 86400 seconds..