last executing test programs:
kernel console output (not intermixed with test programs):
[ 67.759440][ T13] ------------[ cut here ]------------
[ 67.765173][ T13] WARNING: ./include/linux/backing-dev.h:243 at __folio_start_writeback+0x9d5/0xb70, CPU#1: kworker/u8:1/13
[ 67.776771][ T13] Modules linked in:
[ 67.781226][ T13] CPU: 1 UID: 0 PID: 13 Comm: kworker/u8:1 Not tainted syzkaller #0 PREEMPT(full)
[ 67.790611][ T13] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
[ 67.800720][ T13] Workqueue: writeback wb_workfn (flush-8:0)
[ 67.806730][ T13] RIP: 0010:__folio_start_writeback+0x9d5/0xb70
[ 67.813086][ T13] 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 3f 8e 4c 89
[ 67.832861][ T13] RSP: 0018:ffffc90000126ea0 EFLAGS: 00010293
[ 67.839020][ T13] RAX: ffffffff81facb84 RBX: ffffea0000937880 RCX: ffff88801d2b0000
[ 67.846999][ T13] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 67.855044][ T13] RBP: ffffc90000127010 R08: ffffc90000126f97 R09: 0000000000000000
[ 67.863164][ T13] R10: ffffc90000126f80 R11: fffff52000024df3 R12: ffffea0000937888
[ 67.871233][ T13] R13: 0000000000000000 R14: ffff888023033680 R15: ffff888023033460
[ 67.879383][ T13] FS: 0000000000000000(0000) GS:ffff888125af4000(0000) knlGS:0000000000000000
[ 67.888319][ T13] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 67.894988][ T13] CR2: 00007ffdc0a66160 CR3: 000000007af82000 CR4: 00000000003526f0
[ 67.903208][ T13] Call Trace:
[ 67.906478][ T13]
[ 67.909459][ T13] ? folio_clear_dirty_for_io+0x226/0x880
[ 67.915198][ T13] ? __pfx___folio_start_writeback+0x10/0x10
[ 67.921228][ T13] ? __pfx_folio_clear_dirty_for_io+0x10/0x10
[ 67.927501][ T13] ? stack_trace_save+0x9c/0xe0
[ 67.932418][ T13] __block_write_full_folio+0x75f/0xe10
[ 67.938077][ T13] ? __pfx_blkdev_get_block+0x10/0x10
[ 67.943680][ T13] blkdev_writepages+0xd1/0x170
[ 67.948551][ T13] ? __pfx_blkdev_writepages+0x10/0x10
[ 67.954293][ T13] ? __pfx_blkdev_writepages+0x10/0x10
[ 67.959897][ T13] do_writepages+0x32e/0x550
[ 67.964492][ T13] __writeback_single_inode+0x145/0xff0
[ 67.970100][ T13] ? wbc_attach_and_unlock_inode+0x3f0/0x5d0
[ 67.976104][ T13] writeback_sb_inodes+0x6c7/0x1010
[ 67.981482][ T13] ? __pfx_writeback_sb_inodes+0x10/0x10
[ 67.987167][ T13] ? __pfx_down_read_trylock+0x10/0x10
[ 67.992692][ T13] ? __pfx___up_read+0x10/0x10
[ 67.997493][ T13] __writeback_inodes_wb+0x111/0x240
[ 68.002871][ T13] wb_writeback+0x44f/0xaf0
[ 68.007394][ T13] ? queue_io+0x361/0x590
[ 68.011800][ T13] ? __pfx_wb_writeback+0x10/0x10
[ 68.016845][ T13] wb_workfn+0xaef/0xef0
[ 68.022094][ T13] ? __pfx_wb_workfn+0x10/0x10
[ 68.026954][ T13] ? __lock_acquire+0xab9/0xd20
[ 68.031962][ T13] ? process_scheduled_works+0x9ef/0x17b0
[ 68.037760][ T13] ? _raw_spin_unlock_irq+0x23/0x50
[ 68.043070][ T13] ? process_scheduled_works+0x9ef/0x17b0
[ 68.049177][ T13] ? process_scheduled_works+0x9ef/0x17b0
[ 68.054904][ T13] process_scheduled_works+0xade/0x17b0
[ 68.060551][ T13] ? __pfx_process_scheduled_works+0x10/0x10
[ 68.066574][ T13] worker_thread+0x8a0/0xda0
[ 68.071269][ T13] kthread+0x70e/0x8a0
[ 68.075357][ T13] ? __pfx_worker_thread+0x10/0x10
[ 68.080531][ T13] ? __pfx_kthread+0x10/0x10
[ 68.085238][ T13] ? _raw_spin_unlock_irq+0x23/0x50
[ 68.090518][ T13] ? lockdep_hardirqs_on+0x9c/0x150
[ 68.095759][ T13] ? __pfx_kthread+0x10/0x10
[ 68.100414][ T13] ret_from_fork+0x47c/0x820
[ 68.105204][ T13] ? __pfx_ret_from_fork+0x10/0x10
[ 68.110870][ T13] ? __switch_to_asm+0x39/0x70
[ 68.115680][ T13] ? __switch_to_asm+0x33/0x70
[ 68.120514][ T13] ? __pfx_kthread+0x10/0x10
[ 68.125142][ T13] ret_from_fork_asm+0x1a/0x30
[ 68.130138][ T13]
[ 68.133266][ T13] Kernel panic - not syncing: kernel: panic_on_warn set ...
[ 68.140552][ T13] CPU: 1 UID: 0 PID: 13 Comm: kworker/u8:1 Not tainted syzkaller #0 PREEMPT(full)
[ 68.150091][ T13] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
[ 68.160148][ T13] Workqueue: writeback wb_workfn (flush-8:0)
[ 68.166123][ T13] Call Trace:
[ 68.169394][ T13]
[ 68.172306][ T13] dump_stack_lvl+0x99/0x250
[ 68.176910][ T13] ? __asan_memcpy+0x40/0x70
[ 68.181586][ T13] ? __pfx_dump_stack_lvl+0x10/0x10
[ 68.186858][ T13] ? __pfx__printk+0x10/0x10
[ 68.191445][ T13] vpanic+0x229/0x6d0
[ 68.195436][ T13] ? __pfx_vpanic+0x10/0x10
[ 68.199991][ T13] ? is_bpf_text_address+0x292/0x2b0
[ 68.205291][ T13] ? is_bpf_text_address+0x26/0x2b0
[ 68.210497][ T13] panic+0xb9/0xc0
[ 68.214214][ T13] ? __pfx_panic+0x10/0x10
[ 68.218622][ T13] ? ret_from_fork_asm+0x1a/0x30
[ 68.223646][ T13] __warn+0x334/0x4c0
[ 68.227624][ T13] ? __folio_start_writeback+0x9d5/0xb70
[ 68.233253][ T13] ? __folio_start_writeback+0x9d5/0xb70
[ 68.238982][ T13] report_bug+0x2be/0x4f0
[ 68.243330][ T13] ? __folio_start_writeback+0x9d5/0xb70
[ 68.248957][ T13] ? __folio_start_writeback+0x9d5/0xb70
[ 68.254586][ T13] ? __folio_start_writeback+0x9d7/0xb70
[ 68.260307][ T13] handle_bug+0x84/0x160
[ 68.264559][ T13] exc_invalid_op+0x1a/0x50
[ 68.269046][ T13] asm_exc_invalid_op+0x1a/0x20
[ 68.273911][ T13] RIP: 0010:__folio_start_writeback+0x9d5/0xb70
[ 68.280237][ T13] 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 3f 8e 4c 89
[ 68.299924][ T13] RSP: 0018:ffffc90000126ea0 EFLAGS: 00010293
[ 68.305984][ T13] RAX: ffffffff81facb84 RBX: ffffea0000937880 RCX: ffff88801d2b0000
[ 68.313940][ T13] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 68.321922][ T13] RBP: ffffc90000127010 R08: ffffc90000126f97 R09: 0000000000000000
[ 68.329906][ T13] R10: ffffc90000126f80 R11: fffff52000024df3 R12: ffffea0000937888
[ 68.337966][ T13] R13: 0000000000000000 R14: ffff888023033680 R15: ffff888023033460
[ 68.345936][ T13] ? __folio_start_writeback+0x9d4/0xb70
[ 68.351570][ T13] ? folio_clear_dirty_for_io+0x226/0x880
[ 68.357286][ T13] ? __pfx___folio_start_writeback+0x10/0x10
[ 68.363346][ T13] ? __pfx_folio_clear_dirty_for_io+0x10/0x10
[ 68.369400][ T13] ? stack_trace_save+0x9c/0xe0
[ 68.374249][ T13] __block_write_full_folio+0x75f/0xe10
[ 68.379868][ T13] ? __pfx_blkdev_get_block+0x10/0x10
[ 68.385236][ T13] blkdev_writepages+0xd1/0x170
[ 68.390064][ T13] ? __pfx_blkdev_writepages+0x10/0x10
[ 68.395532][ T13] ? __pfx_blkdev_writepages+0x10/0x10
[ 68.401120][ T13] do_writepages+0x32e/0x550
[ 68.405742][ T13] __writeback_single_inode+0x145/0xff0
[ 68.411288][ T13] ? wbc_attach_and_unlock_inode+0x3f0/0x5d0
[ 68.417262][ T13] writeback_sb_inodes+0x6c7/0x1010
[ 68.422491][ T13] ? __pfx_writeback_sb_inodes+0x10/0x10
[ 68.428163][ T13] ? __pfx_down_read_trylock+0x10/0x10
[ 68.433615][ T13] ? __pfx___up_read+0x10/0x10
[ 68.438559][ T13] __writeback_inodes_wb+0x111/0x240
[ 68.443939][ T13] wb_writeback+0x44f/0xaf0
[ 68.448456][ T13] ? queue_io+0x361/0x590
[ 68.452871][ T13] ? __pfx_wb_writeback+0x10/0x10
[ 68.458084][ T13] wb_workfn+0xaef/0xef0
[ 68.462420][ T13] ? __pfx_wb_workfn+0x10/0x10
[ 68.467178][ T13] ? __lock_acquire+0xab9/0xd20
[ 68.472033][ T13] ? process_scheduled_works+0x9ef/0x17b0
[ 68.477782][ T13] ? _raw_spin_unlock_irq+0x23/0x50
[ 68.483607][ T13] ? process_scheduled_works+0x9ef/0x17b0
[ 68.489349][ T13] ? process_scheduled_works+0x9ef/0x17b0
[ 68.495080][ T13] process_scheduled_works+0xade/0x17b0
[ 68.500745][ T13] ? __pfx_process_scheduled_works+0x10/0x10
[ 68.506741][ T13] worker_thread+0x8a0/0xda0
[ 68.511350][ T13] kthread+0x70e/0x8a0
[ 68.515413][ T13] ? __pfx_worker_thread+0x10/0x10
[ 68.520516][ T13] ? __pfx_kthread+0x10/0x10
[ 68.525114][ T13] ? _raw_spin_unlock_irq+0x23/0x50
[ 68.530322][ T13] ? lockdep_hardirqs_on+0x9c/0x150
[ 68.535508][ T13] ? __pfx_kthread+0x10/0x10
[ 68.540091][ T13] ret_from_fork+0x47c/0x820
[ 68.544683][ T13] ? __pfx_ret_from_fork+0x10/0x10
[ 68.549800][ T13] ? __switch_to_asm+0x39/0x70
[ 68.554556][ T13] ? __switch_to_asm+0x33/0x70
[ 68.559310][ T13] ? __pfx_kthread+0x10/0x10
[ 68.563897][ T13] ret_from_fork_asm+0x1a/0x30
[ 68.568668][ T13]
[ 68.571947][ T13] Kernel Offset: disabled
[ 68.576313][ T13] Rebooting in 86400 seconds..