last executing test programs:
kernel console output (not intermixed with test programs):
[ 64.720606][ T12] ------------[ cut here ]------------
[ 64.726176][ T12] WARNING: ./include/linux/backing-dev.h:243 at __folio_start_writeback+0x9d5/0xb70, CPU#0: kworker/u8:0/12
[ 64.737735][ T12] Modules linked in:
[ 64.741781][ T12] CPU: 0 UID: 0 PID: 12 Comm: kworker/u8:0 Not tainted syzkaller #0 PREEMPT(full)
[ 64.751134][ T12] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
[ 64.761229][ T12] Workqueue: writeback wb_workfn (flush-8:0)
[ 64.767234][ T12] RIP: 0010:__folio_start_writeback+0x9d5/0xb70
[ 64.773534][ T12] Code: 28 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 de a2 29 00 49 8b 07 25 ff 3f 00 00 e9 1b fa ff ff e8 dc f7 c5 ff 90 <0f> 0b 90 e9 d6 fb ff ff e8 ce f7 c5 ff 48 c7 c7 e0 fe 5f 8e 4c 89
[ 64.793312][ T12] RSP: 0018:ffffc90000116ea0 EFLAGS: 00010293
[ 64.799388][ T12] RAX: ffffffff81fb0b54 RBX: ffffea000508c880 RCX: ffff88801d29da00
[ 64.807458][ T12] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 64.815615][ T12] RBP: ffffc90000117010 R08: ffffc90000116f97 R09: 0000000000000000
[ 64.823646][ T12] R10: ffffc90000116f80 R11: fffff52000022df3 R12: ffffea000508c888
[ 64.831697][ T12] R13: 0000000000000000 R14: ffff888148c8e480 R15: ffff888148c8e260
[ 64.839658][ T12] FS: 0000000000000000(0000) GS:ffff8881257bf000(0000) knlGS:0000000000000000
[ 64.848652][ T12] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 64.855319][ T12] CR2: 00007f832c28f4c0 CR3: 000000000e338000 CR4: 00000000003526f0
[ 64.863347][ T12] Call Trace:
[ 64.866628][ T12]
[ 64.869561][ T12] ? folio_clear_dirty_for_io+0x226/0x880
[ 64.875344][ T12] ? __pfx___folio_start_writeback+0x10/0x10
[ 64.881564][ T12] ? __pfx_folio_clear_dirty_for_io+0x10/0x10
[ 64.887661][ T12] ? stack_trace_save+0x9c/0xe0
[ 64.892813][ T12] __block_write_full_folio+0x75f/0xe10
[ 64.898430][ T12] ? __pfx_blkdev_get_block+0x10/0x10
[ 64.903885][ T12] blkdev_writepages+0xd1/0x170
[ 64.908774][ T12] ? __pfx_blkdev_writepages+0x10/0x10
[ 64.914541][ T12] ? __pfx_blkdev_writepages+0x10/0x10
[ 64.920051][ T12] do_writepages+0x32b/0x550
[ 64.924659][ T12] __writeback_single_inode+0x145/0xff0
[ 64.930400][ T12] ? wbc_attach_and_unlock_inode+0x3f0/0x5d0
[ 64.936419][ T12] writeback_sb_inodes+0x6c7/0x1010
[ 64.941726][ T12] ? __pfx_writeback_sb_inodes+0x10/0x10
[ 64.947443][ T12] ? __pfx_down_read_trylock+0x10/0x10
[ 64.953042][ T12] ? __pfx___up_read+0x10/0x10
[ 64.957848][ T12] __writeback_inodes_wb+0x111/0x240
[ 64.963247][ T12] wb_writeback+0x44f/0xaf0
[ 64.967763][ T12] ? queue_io+0x381/0x590
[ 64.972159][ T12] ? __pfx_wb_writeback+0x10/0x10
[ 64.977224][ T12] wb_workfn+0xaef/0xef0
[ 64.981972][ T12] ? __pfx_wb_workfn+0x10/0x10
[ 64.986759][ T12] ? __lock_acquire+0xab9/0xd20
[ 64.991680][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 64.997417][ T12] ? _raw_spin_unlock_irq+0x23/0x50
[ 65.002686][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 65.008415][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 65.014197][ T12] process_scheduled_works+0xade/0x17b0
[ 65.019814][ T12] ? __pfx_process_scheduled_works+0x10/0x10
[ 65.025926][ T12] worker_thread+0x8a0/0xda0
[ 65.030609][ T12] kthread+0x70e/0x8a0
[ 65.034670][ T12] ? __pfx_worker_thread+0x10/0x10
[ 65.039758][ T12] ? __pfx_kthread+0x10/0x10
[ 65.044412][ T12] ? _raw_spin_unlock_irq+0x23/0x50
[ 65.049721][ T12] ? lockdep_hardirqs_on+0x9c/0x150
[ 65.054973][ T12] ? __pfx_kthread+0x10/0x10
[ 65.059583][ T12] ret_from_fork+0x47c/0x820
[ 65.064209][ T12] ? __pfx_ret_from_fork+0x10/0x10
[ 65.069342][ T12] ? __switch_to_asm+0x39/0x70
[ 65.074163][ T12] ? __switch_to_asm+0x33/0x70
[ 65.078928][ T12] ? __pfx_kthread+0x10/0x10
[ 65.083556][ T12] ret_from_fork_asm+0x1a/0x30
[ 65.088418][ T12]
[ 65.091495][ T12] Kernel panic - not syncing: kernel: panic_on_warn set ...
[ 65.098783][ T12] CPU: 0 UID: 0 PID: 12 Comm: kworker/u8:0 Not tainted syzkaller #0 PREEMPT(full)
[ 65.108081][ T12] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
[ 65.118117][ T12] Workqueue: writeback wb_workfn (flush-8:0)
[ 65.124092][ T12] Call Trace:
[ 65.127361][ T12]
[ 65.130362][ T12] dump_stack_lvl+0x99/0x250
[ 65.134935][ T12] ? __asan_memcpy+0x40/0x70
[ 65.139594][ T12] ? __pfx_dump_stack_lvl+0x10/0x10
[ 65.144775][ T12] ? __pfx__printk+0x10/0x10
[ 65.149361][ T12] vpanic+0x229/0x6d0
[ 65.153352][ T12] ? __pfx_vpanic+0x10/0x10
[ 65.157846][ T12] ? is_bpf_text_address+0x292/0x2b0
[ 65.163120][ T12] ? is_bpf_text_address+0x26/0x2b0
[ 65.168311][ T12] panic+0xb9/0xc0
[ 65.172024][ T12] ? __pfx_panic+0x10/0x10
[ 65.176436][ T12] ? ret_from_fork_asm+0x1a/0x30
[ 65.181364][ T12] __warn+0x334/0x4c0
[ 65.185333][ T12] ? __folio_start_writeback+0x9d5/0xb70
[ 65.190961][ T12] ? __folio_start_writeback+0x9d5/0xb70
[ 65.196580][ T12] report_bug+0x2be/0x4f0
[ 65.200899][ T12] ? __folio_start_writeback+0x9d5/0xb70
[ 65.206517][ T12] ? __folio_start_writeback+0x9d5/0xb70
[ 65.212158][ T12] ? __folio_start_writeback+0x9d7/0xb70
[ 65.217886][ T12] handle_bug+0x84/0x160
[ 65.222206][ T12] exc_invalid_op+0x1a/0x50
[ 65.226706][ T12] asm_exc_invalid_op+0x1a/0x20
[ 65.231546][ T12] RIP: 0010:__folio_start_writeback+0x9d5/0xb70
[ 65.237773][ T12] Code: 28 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 de a2 29 00 49 8b 07 25 ff 3f 00 00 e9 1b fa ff ff e8 dc f7 c5 ff 90 <0f> 0b 90 e9 d6 fb ff ff e8 ce f7 c5 ff 48 c7 c7 e0 fe 5f 8e 4c 89
[ 65.257491][ T12] RSP: 0018:ffffc90000116ea0 EFLAGS: 00010293
[ 65.263556][ T12] RAX: ffffffff81fb0b54 RBX: ffffea000508c880 RCX: ffff88801d29da00
[ 65.271516][ T12] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 65.279484][ T12] RBP: ffffc90000117010 R08: ffffc90000116f97 R09: 0000000000000000
[ 65.287443][ T12] R10: ffffc90000116f80 R11: fffff52000022df3 R12: ffffea000508c888
[ 65.295399][ T12] R13: 0000000000000000 R14: ffff888148c8e480 R15: ffff888148c8e260
[ 65.303364][ T12] ? __folio_start_writeback+0x9d4/0xb70
[ 65.309004][ T12] ? folio_clear_dirty_for_io+0x226/0x880
[ 65.314717][ T12] ? __pfx___folio_start_writeback+0x10/0x10
[ 65.320684][ T12] ? __pfx_folio_clear_dirty_for_io+0x10/0x10
[ 65.326826][ T12] ? stack_trace_save+0x9c/0xe0
[ 65.331673][ T12] __block_write_full_folio+0x75f/0xe10
[ 65.337217][ T12] ? __pfx_blkdev_get_block+0x10/0x10
[ 65.342592][ T12] blkdev_writepages+0xd1/0x170
[ 65.347525][ T12] ? __pfx_blkdev_writepages+0x10/0x10
[ 65.353074][ T12] ? __pfx_blkdev_writepages+0x10/0x10
[ 65.358537][ T12] do_writepages+0x32b/0x550
[ 65.363144][ T12] __writeback_single_inode+0x145/0xff0
[ 65.368686][ T12] ? wbc_attach_and_unlock_inode+0x3f0/0x5d0
[ 65.374761][ T12] writeback_sb_inodes+0x6c7/0x1010
[ 65.379977][ T12] ? __pfx_writeback_sb_inodes+0x10/0x10
[ 65.385625][ T12] ? __pfx_down_read_trylock+0x10/0x10
[ 65.391081][ T12] ? __pfx___up_read+0x10/0x10
[ 65.395850][ T12] __writeback_inodes_wb+0x111/0x240
[ 65.401131][ T12] wb_writeback+0x44f/0xaf0
[ 65.405625][ T12] ? queue_io+0x381/0x590
[ 65.409945][ T12] ? __pfx_wb_writeback+0x10/0x10
[ 65.414972][ T12] wb_workfn+0xaef/0xef0
[ 65.419224][ T12] ? __pfx_wb_workfn+0x10/0x10
[ 65.423994][ T12] ? __lock_acquire+0xab9/0xd20
[ 65.428849][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 65.434561][ T12] ? _raw_spin_unlock_irq+0x23/0x50
[ 65.439757][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 65.445464][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 65.451180][ T12] process_scheduled_works+0xade/0x17b0
[ 65.456750][ T12] ? __pfx_process_scheduled_works+0x10/0x10
[ 65.462741][ T12] worker_thread+0x8a0/0xda0
[ 65.467348][ T12] kthread+0x70e/0x8a0
[ 65.471408][ T12] ? __pfx_worker_thread+0x10/0x10
[ 65.476505][ T12] ? __pfx_kthread+0x10/0x10
[ 65.481174][ T12] ? _raw_spin_unlock_irq+0x23/0x50
[ 65.486362][ T12] ? lockdep_hardirqs_on+0x9c/0x150
[ 65.491541][ T12] ? __pfx_kthread+0x10/0x10
[ 65.496500][ T12] ret_from_fork+0x47c/0x820
[ 65.501087][ T12] ? __pfx_ret_from_fork+0x10/0x10
[ 65.506229][ T12] ? __switch_to_asm+0x39/0x70
[ 65.510983][ T12] ? __switch_to_asm+0x33/0x70
[ 65.515738][ T12] ? __pfx_kthread+0x10/0x10
[ 65.520331][ T12] ret_from_fork_asm+0x1a/0x30
[ 65.525142][ T12]
[ 65.528402][ T12] Kernel Offset: disabled
[ 65.532771][ T12] Rebooting in 86400 seconds..