last executing test programs:
kernel console output (not intermixed with test programs):
[ 68.403499][ T12] ------------[ cut here ]------------
[ 68.409300][ T12] WARNING: ./include/linux/backing-dev.h:243 at __folio_start_writeback+0x9d5/0xb70, CPU#0: kworker/u8:0/12
[ 68.421518][ T12] Modules linked in:
[ 68.425606][ T12] CPU: 0 UID: 0 PID: 12 Comm: kworker/u8:0 Not tainted syzkaller #0 PREEMPT(full)
[ 68.435147][ T12] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
[ 68.445638][ T12] Workqueue: writeback wb_workfn (flush-8:0)
[ 68.451688][ T12] RIP: 0010:__folio_start_writeback+0x9d5/0xb70
[ 68.458029][ T12] Code: 28 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 0e 02 2a 00 49 8b 07 25 ff 3f 00 00 e9 1b fa ff ff e8 bc f7 c5 ff 90 <0f> 0b 90 e9 d6 fb ff ff e8 ae f7 c5 ff 48 c7 c7 e0 fe 5f 8e 4c 89
[ 68.477882][ T12] RSP: 0018:ffffc90000116ea0 EFLAGS: 00010293
[ 68.484121][ T12] RAX: ffffffff81fb0b84 RBX: ffffea00050bf180 RCX: ffff88801d295a00
[ 68.492213][ T12] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 68.500360][ T12] RBP: ffffc90000117010 R08: ffffc90000116f97 R09: 0000000000000000
[ 68.508486][ T12] R10: ffffc90000116f80 R11: fffff52000022df3 R12: ffffea00050bf188
[ 68.516738][ T12] R13: 0000000000000000 R14: ffff888148c0b680 R15: ffff888148c0b460
[ 68.524774][ T12] FS: 0000000000000000(0000) GS:ffff8881257ba000(0000) knlGS:0000000000000000
[ 68.533906][ T12] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 68.540522][ T12] CR2: 0000557aafd2b030 CR3: 0000000063032000 CR4: 00000000003526f0
[ 68.549360][ T12] Call Trace:
[ 68.552671][ T12]
[ 68.555789][ T12] ? folio_clear_dirty_for_io+0x226/0x880
[ 68.561557][ T12] ? __pfx___folio_start_writeback+0x10/0x10
[ 68.567686][ T12] ? __pfx_folio_clear_dirty_for_io+0x10/0x10
[ 68.573939][ T12] ? stack_trace_save+0x9c/0xe0
[ 68.578842][ T12] __block_write_full_folio+0x75f/0xe10
[ 68.584484][ T12] ? __pfx_blkdev_get_block+0x10/0x10
[ 68.589974][ T12] blkdev_writepages+0xd1/0x170
[ 68.595042][ T12] ? __pfx_blkdev_writepages+0x10/0x10
[ 68.600567][ T12] ? __pfx_blkdev_writepages+0x10/0x10
[ 68.606255][ T12] do_writepages+0x32e/0x550
[ 68.610893][ T12] __writeback_single_inode+0x145/0xff0
[ 68.616736][ T12] ? wbc_attach_and_unlock_inode+0x3f0/0x5d0
[ 68.622885][ T12] writeback_sb_inodes+0x6c7/0x1010
[ 68.628263][ T12] ? __pfx_writeback_sb_inodes+0x10/0x10
[ 68.634267][ T12] ? __pfx_down_read_trylock+0x10/0x10
[ 68.639859][ T12] ? __pfx___up_read+0x10/0x10
[ 68.644739][ T12] __writeback_inodes_wb+0x111/0x240
[ 68.650084][ T12] wb_writeback+0x44f/0xaf0
[ 68.654674][ T12] ? queue_io+0x331/0x590
[ 68.659037][ T12] ? __pfx_wb_writeback+0x10/0x10
[ 68.664166][ T12] wb_workfn+0xaef/0xef0
[ 68.668512][ T12] ? __pfx_wb_workfn+0x10/0x10
[ 68.673343][ T12] ? __lock_acquire+0xab9/0xd20
[ 68.678510][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 68.684426][ T12] ? _raw_spin_unlock_irq+0x23/0x50
[ 68.689861][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 68.695870][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 68.701987][ T12] process_scheduled_works+0xade/0x17b0
[ 68.708323][ T12] ? __pfx_process_scheduled_works+0x10/0x10
[ 68.714584][ T12] worker_thread+0x8a0/0xda0
[ 68.719261][ T12] kthread+0x70e/0x8a0
[ 68.723451][ T12] ? __pfx_worker_thread+0x10/0x10
[ 68.728609][ T12] ? __pfx_kthread+0x10/0x10
[ 68.733431][ T12] ? _raw_spin_unlock_irq+0x23/0x50
[ 68.739007][ T12] ? lockdep_hardirqs_on+0x9c/0x150
[ 68.744525][ T12] ? __pfx_kthread+0x10/0x10
[ 68.749435][ T12] ret_from_fork+0x47c/0x820
[ 68.754271][ T12] ? __pfx_ret_from_fork+0x10/0x10
[ 68.759531][ T12] ? __switch_to_asm+0x39/0x70
[ 68.764438][ T12] ? __switch_to_asm+0x33/0x70
[ 68.769485][ T12] ? __pfx_kthread+0x10/0x10
[ 68.774230][ T12] ret_from_fork_asm+0x1a/0x30
[ 68.779056][ T12]
[ 68.782176][ T12] Kernel panic - not syncing: kernel: panic_on_warn set ...
[ 68.789561][ T12] CPU: 0 UID: 0 PID: 12 Comm: kworker/u8:0 Not tainted syzkaller #0 PREEMPT(full)
[ 68.799111][ T12] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
[ 68.809281][ T12] Workqueue: writeback wb_workfn (flush-8:0)
[ 68.815323][ T12] Call Trace:
[ 68.818628][ T12]
[ 68.821670][ T12] dump_stack_lvl+0x99/0x250
[ 68.826297][ T12] ? __asan_memcpy+0x40/0x70
[ 68.831105][ T12] ? __pfx_dump_stack_lvl+0x10/0x10
[ 68.836522][ T12] ? __pfx__printk+0x10/0x10
[ 68.841249][ T12] vpanic+0x229/0x6d0
[ 68.845287][ T12] ? __pfx_vpanic+0x10/0x10
[ 68.849925][ T12] ? is_bpf_text_address+0x292/0x2b0
[ 68.855366][ T12] ? is_bpf_text_address+0x26/0x2b0
[ 68.860623][ T12] panic+0xb9/0xc0
[ 68.864517][ T12] ? __pfx_panic+0x10/0x10
[ 68.869000][ T12] ? ret_from_fork_asm+0x1a/0x30
[ 68.873972][ T12] __warn+0x334/0x4c0
[ 68.878005][ T12] ? __folio_start_writeback+0x9d5/0xb70
[ 68.883677][ T12] ? __folio_start_writeback+0x9d5/0xb70
[ 68.889330][ T12] report_bug+0x2be/0x4f0
[ 68.893669][ T12] ? __folio_start_writeback+0x9d5/0xb70
[ 68.899385][ T12] ? __folio_start_writeback+0x9d5/0xb70
[ 68.905113][ T12] ? __folio_start_writeback+0x9d7/0xb70
[ 68.910932][ T12] handle_bug+0x84/0x160
[ 68.915190][ T12] exc_invalid_op+0x1a/0x50
[ 68.919689][ T12] asm_exc_invalid_op+0x1a/0x20
[ 68.924622][ T12] RIP: 0010:__folio_start_writeback+0x9d5/0xb70
[ 68.931051][ T12] Code: 28 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 0e 02 2a 00 49 8b 07 25 ff 3f 00 00 e9 1b fa ff ff e8 bc f7 c5 ff 90 <0f> 0b 90 e9 d6 fb ff ff e8 ae f7 c5 ff 48 c7 c7 e0 fe 5f 8e 4c 89
[ 68.950909][ T12] RSP: 0018:ffffc90000116ea0 EFLAGS: 00010293
[ 68.957025][ T12] RAX: ffffffff81fb0b84 RBX: ffffea00050bf180 RCX: ffff88801d295a00
[ 68.965080][ T12] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 68.973056][ T12] RBP: ffffc90000117010 R08: ffffc90000116f97 R09: 0000000000000000
[ 68.981025][ T12] R10: ffffc90000116f80 R11: fffff52000022df3 R12: ffffea00050bf188
[ 68.989030][ T12] R13: 0000000000000000 R14: ffff888148c0b680 R15: ffff888148c0b460
[ 68.997023][ T12] ? __folio_start_writeback+0x9d4/0xb70
[ 69.002672][ T12] ? folio_clear_dirty_for_io+0x226/0x880
[ 69.008400][ T12] ? __pfx___folio_start_writeback+0x10/0x10
[ 69.014377][ T12] ? __pfx_folio_clear_dirty_for_io+0x10/0x10
[ 69.020442][ T12] ? stack_trace_save+0x9c/0xe0
[ 69.025401][ T12] __block_write_full_folio+0x75f/0xe10
[ 69.031039][ T12] ? __pfx_blkdev_get_block+0x10/0x10
[ 69.036414][ T12] blkdev_writepages+0xd1/0x170
[ 69.041447][ T12] ? __pfx_blkdev_writepages+0x10/0x10
[ 69.047196][ T12] ? __pfx_blkdev_writepages+0x10/0x10
[ 69.052683][ T12] do_writepages+0x32e/0x550
[ 69.057311][ T12] __writeback_single_inode+0x145/0xff0
[ 69.062953][ T12] ? wbc_attach_and_unlock_inode+0x3f0/0x5d0
[ 69.069037][ T12] writeback_sb_inodes+0x6c7/0x1010
[ 69.074294][ T12] ? __pfx_writeback_sb_inodes+0x10/0x10
[ 69.080016][ T12] ? __pfx_down_read_trylock+0x10/0x10
[ 69.085516][ T12] ? __pfx___up_read+0x10/0x10
[ 69.090405][ T12] __writeback_inodes_wb+0x111/0x240
[ 69.095847][ T12] wb_writeback+0x44f/0xaf0
[ 69.100422][ T12] ? queue_io+0x331/0x590
[ 69.104863][ T12] ? __pfx_wb_writeback+0x10/0x10
[ 69.110173][ T12] wb_workfn+0xaef/0xef0
[ 69.114482][ T12] ? __pfx_wb_workfn+0x10/0x10
[ 69.119375][ T12] ? __lock_acquire+0xab9/0xd20
[ 69.124329][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 69.130139][ T12] ? _raw_spin_unlock_irq+0x23/0x50
[ 69.135523][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 69.141331][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 69.147095][ T12] process_scheduled_works+0xade/0x17b0
[ 69.152687][ T12] ? __pfx_process_scheduled_works+0x10/0x10
[ 69.158943][ T12] worker_thread+0x8a0/0xda0
[ 69.163559][ T12] kthread+0x70e/0x8a0
[ 69.167635][ T12] ? __pfx_worker_thread+0x10/0x10
[ 69.172743][ T12] ? __pfx_kthread+0x10/0x10
[ 69.177390][ T12] ? _raw_spin_unlock_irq+0x23/0x50
[ 69.182671][ T12] ? lockdep_hardirqs_on+0x9c/0x150
[ 69.187861][ T12] ? __pfx_kthread+0x10/0x10
[ 69.192454][ T12] ret_from_fork+0x47c/0x820
[ 69.197140][ T12] ? __pfx_ret_from_fork+0x10/0x10
[ 69.202275][ T12] ? __switch_to_asm+0x39/0x70
[ 69.207374][ T12] ? __switch_to_asm+0x33/0x70
[ 69.212298][ T12] ? __pfx_kthread+0x10/0x10
[ 69.216905][ T12] ret_from_fork_asm+0x1a/0x30
[ 69.221698][ T12]
[ 69.224980][ T12] Kernel Offset: disabled
[ 69.229306][ T12] Rebooting in 86400 seconds..