last executing test programs:
kernel console output (not intermixed with test programs):
[ 66.266244][ T1159] ------------[ cut here ]------------
[ 66.271960][ T1159] WARNING: ./include/linux/backing-dev.h:243 at __folio_start_writeback+0x9d5/0xb70, CPU#1: kworker/u8:6/1159
[ 66.284005][ T1159] Modules linked in:
[ 66.288310][ T1159] CPU: 1 UID: 0 PID: 1159 Comm: kworker/u8:6 Not tainted syzkaller #0 PREEMPT(full)
[ 66.298378][ T1159] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
[ 66.309481][ T1159] Workqueue: writeback wb_workfn (flush-8:0)
[ 66.316007][ T1159] RIP: 0010:__folio_start_writeback+0x9d5/0xb70
[ 66.322246][ T1159] 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
[ 66.342220][ T1159] RSP: 0018:ffffc90003d26ea0 EFLAGS: 00010293
[ 66.348499][ T1159] RAX: ffffffff81fb0b84 RBX: ffffea000508eb80 RCX: ffff888027085a00
[ 66.356514][ T1159] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 66.364515][ T1159] RBP: ffffc90003d27010 R08: ffffc90003d26f97 R09: 0000000000000000
[ 66.372625][ T1159] R10: ffffc90003d26f80 R11: fffff520007a4df3 R12: ffffea000508eb88
[ 66.380625][ T1159] R13: 0000000000000000 R14: ffff88802553c200 R15: ffff88802553bfe0
[ 66.388645][ T1159] FS: 0000000000000000(0000) GS:ffff8881258ba000(0000) knlGS:0000000000000000
[ 66.397602][ T1159] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 66.404193][ T1159] CR2: 00005566fbf6e660 CR3: 0000000060d68000 CR4: 00000000003526f0
[ 66.412213][ T1159] Call Trace:
[ 66.415495][ T1159]
[ 66.418464][ T1159] ? folio_clear_dirty_for_io+0x226/0x880
[ 66.424211][ T1159] ? __pfx___folio_start_writeback+0x10/0x10
[ 66.430741][ T1159] ? __pfx_folio_clear_dirty_for_io+0x10/0x10
[ 66.436857][ T1159] ? stack_trace_save+0x9c/0xe0
[ 66.441743][ T1159] __block_write_full_folio+0x75f/0xe10
[ 66.447350][ T1159] ? __pfx_blkdev_get_block+0x10/0x10
[ 66.452743][ T1159] blkdev_writepages+0xd1/0x170
[ 66.457649][ T1159] ? __pfx_blkdev_writepages+0x10/0x10
[ 66.463144][ T1159] ? __pfx_blkdev_writepages+0x10/0x10
[ 66.468841][ T1159] do_writepages+0x32e/0x550
[ 66.473473][ T1159] __writeback_single_inode+0x145/0xff0
[ 66.479061][ T1159] ? wbc_attach_and_unlock_inode+0x3f0/0x5d0
[ 66.485075][ T1159] writeback_sb_inodes+0x6c7/0x1010
[ 66.490333][ T1159] ? __pfx_writeback_sb_inodes+0x10/0x10
[ 66.496036][ T1159] ? __pfx_down_read_trylock+0x10/0x10
[ 66.501497][ T1159] ? __pfx___up_read+0x10/0x10
[ 66.506296][ T1159] __writeback_inodes_wb+0x111/0x240
[ 66.511614][ T1159] wb_writeback+0x44f/0xaf0
[ 66.516172][ T1159] ? queue_io+0x331/0x590
[ 66.520509][ T1159] ? __pfx_wb_writeback+0x10/0x10
[ 66.525598][ T1159] wb_workfn+0xaef/0xef0
[ 66.529859][ T1159] ? __pfx_wb_workfn+0x10/0x10
[ 66.534645][ T1159] ? __lock_acquire+0xab9/0xd20
[ 66.539552][ T1159] ? process_scheduled_works+0x9ef/0x17b0
[ 66.545291][ T1159] ? _raw_spin_unlock_irq+0x23/0x50
[ 66.550645][ T1159] ? process_scheduled_works+0x9ef/0x17b0
[ 66.556431][ T1159] ? process_scheduled_works+0x9ef/0x17b0
[ 66.562170][ T1159] process_scheduled_works+0xade/0x17b0
[ 66.567790][ T1159] ? __pfx_process_scheduled_works+0x10/0x10
[ 66.573806][ T1159] worker_thread+0x8a0/0xda0
[ 66.578567][ T1159] ? __pfx__raw_spin_unlock_irqrestore+0x10/0x10
[ 66.584908][ T1159] ? __kthread_parkme+0x7b/0x200
[ 66.589890][ T1159] kthread+0x70e/0x8a0
[ 66.593972][ T1159] ? __pfx_worker_thread+0x10/0x10
[ 66.599111][ T1159] ? __pfx_kthread+0x10/0x10
[ 66.603723][ T1159] ? _raw_spin_unlock_irq+0x23/0x50
[ 66.608962][ T1159] ? lockdep_hardirqs_on+0x9c/0x150
[ 66.614166][ T1159] ? __pfx_kthread+0x10/0x10
[ 66.618795][ T1159] ret_from_fork+0x47c/0x820
[ 66.623432][ T1159] ? __pfx_ret_from_fork+0x10/0x10
[ 66.628579][ T1159] ? __switch_to_asm+0x39/0x70
[ 66.633349][ T1159] ? __switch_to_asm+0x33/0x70
[ 66.638169][ T1159] ? __pfx_kthread+0x10/0x10
[ 66.642794][ T1159] ret_from_fork_asm+0x1a/0x30
[ 66.647678][ T1159]
[ 66.650697][ T1159] Kernel panic - not syncing: kernel: panic_on_warn set ...
[ 66.657960][ T1159] CPU: 1 UID: 0 PID: 1159 Comm: kworker/u8:6 Not tainted syzkaller #0 PREEMPT(full)
[ 66.667431][ T1159] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
[ 66.677469][ T1159] Workqueue: writeback wb_workfn (flush-8:0)
[ 66.683449][ T1159] Call Trace:
[ 66.686734][ T1159]
[ 66.689677][ T1159] dump_stack_lvl+0x99/0x250
[ 66.694281][ T1159] ? __asan_memcpy+0x40/0x70
[ 66.698874][ T1159] ? __pfx_dump_stack_lvl+0x10/0x10
[ 66.704076][ T1159] ? __pfx__printk+0x10/0x10
[ 66.708676][ T1159] vpanic+0x229/0x6d0
[ 66.712655][ T1159] ? __pfx_vpanic+0x10/0x10
[ 66.717152][ T1159] ? is_bpf_text_address+0x292/0x2b0
[ 66.722429][ T1159] ? is_bpf_text_address+0x26/0x2b0
[ 66.727630][ T1159] panic+0xb9/0xc0
[ 66.731363][ T1159] ? __pfx_panic+0x10/0x10
[ 66.735798][ T1159] ? ret_from_fork_asm+0x1a/0x30
[ 66.740730][ T1159] __warn+0x334/0x4c0
[ 66.744710][ T1159] ? __folio_start_writeback+0x9d5/0xb70
[ 66.750338][ T1159] ? __folio_start_writeback+0x9d5/0xb70
[ 66.755962][ T1159] report_bug+0x2be/0x4f0
[ 66.760300][ T1159] ? __folio_start_writeback+0x9d5/0xb70
[ 66.765944][ T1159] ? __folio_start_writeback+0x9d5/0xb70
[ 66.772113][ T1159] ? __folio_start_writeback+0x9d7/0xb70
[ 66.777779][ T1159] handle_bug+0x84/0x160
[ 66.782118][ T1159] exc_invalid_op+0x1a/0x50
[ 66.786622][ T1159] asm_exc_invalid_op+0x1a/0x20
[ 66.791465][ T1159] RIP: 0010:__folio_start_writeback+0x9d5/0xb70
[ 66.797736][ T1159] 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
[ 66.817335][ T1159] RSP: 0018:ffffc90003d26ea0 EFLAGS: 00010293
[ 66.823404][ T1159] RAX: ffffffff81fb0b84 RBX: ffffea000508eb80 RCX: ffff888027085a00
[ 66.831382][ T1159] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 66.839343][ T1159] RBP: ffffc90003d27010 R08: ffffc90003d26f97 R09: 0000000000000000
[ 66.847366][ T1159] R10: ffffc90003d26f80 R11: fffff520007a4df3 R12: ffffea000508eb88
[ 66.855358][ T1159] R13: 0000000000000000 R14: ffff88802553c200 R15: ffff88802553bfe0
[ 66.863347][ T1159] ? __folio_start_writeback+0x9d4/0xb70
[ 66.868995][ T1159] ? folio_clear_dirty_for_io+0x226/0x880
[ 66.874736][ T1159] ? __pfx___folio_start_writeback+0x10/0x10
[ 66.880781][ T1159] ? __pfx_folio_clear_dirty_for_io+0x10/0x10
[ 66.886865][ T1159] ? stack_trace_save+0x9c/0xe0
[ 66.891812][ T1159] __block_write_full_folio+0x75f/0xe10
[ 66.897357][ T1159] ? __pfx_blkdev_get_block+0x10/0x10
[ 66.902736][ T1159] blkdev_writepages+0xd1/0x170
[ 66.907616][ T1159] ? __pfx_blkdev_writepages+0x10/0x10
[ 66.913083][ T1159] ? __pfx_blkdev_writepages+0x10/0x10
[ 66.918584][ T1159] do_writepages+0x32e/0x550
[ 66.923183][ T1159] __writeback_single_inode+0x145/0xff0
[ 66.928825][ T1159] ? wbc_attach_and_unlock_inode+0x3f0/0x5d0
[ 66.934813][ T1159] writeback_sb_inodes+0x6c7/0x1010
[ 66.940057][ T1159] ? __pfx_writeback_sb_inodes+0x10/0x10
[ 66.945717][ T1159] ? __pfx_down_read_trylock+0x10/0x10
[ 66.951176][ T1159] ? __pfx___up_read+0x10/0x10
[ 66.955959][ T1159] __writeback_inodes_wb+0x111/0x240
[ 66.961253][ T1159] wb_writeback+0x44f/0xaf0
[ 66.965800][ T1159] ? queue_io+0x331/0x590
[ 66.970160][ T1159] ? __pfx_wb_writeback+0x10/0x10
[ 66.975213][ T1159] wb_workfn+0xaef/0xef0
[ 66.979468][ T1159] ? __pfx_wb_workfn+0x10/0x10
[ 66.984228][ T1159] ? __lock_acquire+0xab9/0xd20
[ 66.989088][ T1159] ? process_scheduled_works+0x9ef/0x17b0
[ 66.994828][ T1159] ? _raw_spin_unlock_irq+0x23/0x50
[ 67.000019][ T1159] ? process_scheduled_works+0x9ef/0x17b0
[ 67.005861][ T1159] ? process_scheduled_works+0x9ef/0x17b0
[ 67.011581][ T1159] process_scheduled_works+0xade/0x17b0
[ 67.017149][ T1159] ? __pfx_process_scheduled_works+0x10/0x10
[ 67.023140][ T1159] worker_thread+0x8a0/0xda0
[ 67.027732][ T1159] ? __pfx__raw_spin_unlock_irqrestore+0x10/0x10
[ 67.034065][ T1159] ? __kthread_parkme+0x7b/0x200
[ 67.039013][ T1159] kthread+0x70e/0x8a0
[ 67.043086][ T1159] ? __pfx_worker_thread+0x10/0x10
[ 67.048204][ T1159] ? __pfx_kthread+0x10/0x10
[ 67.052837][ T1159] ? _raw_spin_unlock_irq+0x23/0x50
[ 67.058145][ T1159] ? lockdep_hardirqs_on+0x9c/0x150
[ 67.063344][ T1159] ? __pfx_kthread+0x10/0x10
[ 67.067936][ T1159] ret_from_fork+0x47c/0x820
[ 67.072525][ T1159] ? __pfx_ret_from_fork+0x10/0x10
[ 67.077636][ T1159] ? __switch_to_asm+0x39/0x70
[ 67.082498][ T1159] ? __switch_to_asm+0x33/0x70
[ 67.087251][ T1159] ? __pfx_kthread+0x10/0x10
[ 67.091931][ T1159] ret_from_fork_asm+0x1a/0x30
[ 67.096708][ T1159]
[ 67.100061][ T1159] Kernel Offset: disabled
[ 67.104467][ T1159] Rebooting in 86400 seconds..