last executing test programs:
kernel console output (not intermixed with test programs):
[ 65.073376][ T12] ------------[ cut here ]------------
[ 65.078973][ T12] WARNING: ./include/linux/backing-dev.h:243 at __folio_start_writeback+0x8e7/0xa50, CPU#1: kworker/u8:0/12
[ 65.090588][ T12] Modules linked in:
[ 65.094712][ T12] CPU: 1 UID: 0 PID: 12 Comm: kworker/u8:0 Not tainted syzkaller #0 PREEMPT(full)
[ 65.104177][ T12] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
[ 65.114599][ T12] Workqueue: writeback wb_workfn (flush-8:0)
[ 65.120702][ T12] RIP: 0010:__folio_start_writeback+0x8e7/0xa50
[ 65.127046][ T12] 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
[ 65.146772][ T12] RSP: 0018:ffffc90000116ea0 EFLAGS: 00010293
[ 65.152903][ T12] RAX: ffffffff81fad086 RBX: ffffea000092b480 RCX: ffff88801d2a5a00
[ 65.160923][ T12] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 65.169058][ T12] RBP: ffffc90000117010 R08: ffffc90000116f97 R09: 0000000000000000
[ 65.177147][ T12] R10: ffffc90000116f80 R11: fffff52000022df3 R12: ffffea000092b488
[ 65.185229][ T12] R13: 0000000000000000 R14: ffff888148c9cd80 R15: ffff888148c9cb60
[ 65.193248][ T12] FS: 0000000000000000(0000) GS:ffff888125af7000(0000) knlGS:0000000000000000
[ 65.202285][ T12] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 65.208964][ T12] CR2: 000055941c00d168 CR3: 000000000e138000 CR4: 00000000003526f0
[ 65.217007][ T12] Call Trace:
[ 65.220337][ T12]
[ 65.223433][ T12] ? __pfx___folio_start_writeback+0x10/0x10
[ 65.229534][ T12] ? __pfx_folio_clear_dirty_for_io+0x10/0x10
[ 65.235963][ T12] ? stack_trace_save+0x9c/0xe0
[ 65.240828][ T12] __block_write_full_folio+0x75f/0xe10
[ 65.246524][ T12] ? __pfx_blkdev_get_block+0x10/0x10
[ 65.251922][ T12] blkdev_writepages+0xd1/0x170
[ 65.256892][ T12] ? __pfx_blkdev_writepages+0x10/0x10
[ 65.262408][ T12] ? __pfx_blkdev_writepages+0x10/0x10
[ 65.268077][ T12] do_writepages+0x32b/0x550
[ 65.272881][ T12] __writeback_single_inode+0x145/0xff0
[ 65.278657][ T12] ? wbc_attach_and_unlock_inode+0x3f0/0x5d0
[ 65.285389][ T12] writeback_sb_inodes+0x6c7/0x1010
[ 65.290738][ T12] ? __pfx_writeback_sb_inodes+0x10/0x10
[ 65.296591][ T12] ? __pfx_down_read_trylock+0x10/0x10
[ 65.302070][ T12] ? __pfx___up_read+0x10/0x10
[ 65.306915][ T12] __writeback_inodes_wb+0x111/0x240
[ 65.312252][ T12] wb_writeback+0x44f/0xaf0
[ 65.316965][ T12] ? queue_io+0x3d1/0x590
[ 65.321493][ T12] ? __pfx_wb_writeback+0x10/0x10
[ 65.326621][ T12] wb_workfn+0xaef/0xef0
[ 65.330891][ T12] ? __pfx_wb_workfn+0x10/0x10
[ 65.335721][ T12] ? __lock_acquire+0xab9/0xd20
[ 65.340682][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 65.346660][ T12] ? _raw_spin_unlock_irq+0x23/0x50
[ 65.351910][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 65.357722][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 65.363602][ T12] process_scheduled_works+0xade/0x17b0
[ 65.369271][ T12] ? __pfx_process_scheduled_works+0x10/0x10
[ 65.375318][ T12] worker_thread+0x8a0/0xda0
[ 65.379931][ T12] kthread+0x70e/0x8a0
[ 65.384082][ T12] ? __pfx_worker_thread+0x10/0x10
[ 65.389199][ T12] ? __pfx_kthread+0x10/0x10
[ 65.393853][ T12] ? _raw_spin_unlock_irq+0x23/0x50
[ 65.399079][ T12] ? lockdep_hardirqs_on+0x9c/0x150
[ 65.404361][ T12] ? __pfx_kthread+0x10/0x10
[ 65.408979][ T12] ret_from_fork+0x47c/0x820
[ 65.413816][ T12] ? __pfx_ret_from_fork+0x10/0x10
[ 65.418958][ T12] ? __switch_to_asm+0x39/0x70
[ 65.423780][ T12] ? __switch_to_asm+0x33/0x70
[ 65.428552][ T12] ? __pfx_kthread+0x10/0x10
[ 65.433223][ T12] ret_from_fork_asm+0x1a/0x30
[ 65.438061][ T12]
[ 65.441105][ T12] Kernel panic - not syncing: kernel: panic_on_warn set ...
[ 65.448389][ T12] CPU: 1 UID: 0 PID: 12 Comm: kworker/u8:0 Not tainted syzkaller #0 PREEMPT(full)
[ 65.457749][ T12] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
[ 65.467894][ T12] Workqueue: writeback wb_workfn (flush-8:0)
[ 65.473985][ T12] Call Trace:
[ 65.477258][ T12]
[ 65.480195][ T12] dump_stack_lvl+0x99/0x250
[ 65.484780][ T12] ? __asan_memcpy+0x40/0x70
[ 65.489457][ T12] ? __pfx_dump_stack_lvl+0x10/0x10
[ 65.494740][ T12] ? __pfx__printk+0x10/0x10
[ 65.499434][ T12] vpanic+0x229/0x6d0
[ 65.503403][ T12] ? __pfx_vpanic+0x10/0x10
[ 65.507896][ T12] ? is_bpf_text_address+0x292/0x2b0
[ 65.513171][ T12] ? is_bpf_text_address+0x26/0x2b0
[ 65.518484][ T12] panic+0xb9/0xc0
[ 65.522203][ T12] ? __pfx_panic+0x10/0x10
[ 65.526727][ T12] ? ret_from_fork_asm+0x1a/0x30
[ 65.531770][ T12] __warn+0x334/0x4c0
[ 65.535742][ T12] ? __folio_start_writeback+0x8e7/0xa50
[ 65.541483][ T12] ? __folio_start_writeback+0x8e7/0xa50
[ 65.547184][ T12] report_bug+0x2be/0x4f0
[ 65.551678][ T12] ? __folio_start_writeback+0x8e7/0xa50
[ 65.557324][ T12] ? __folio_start_writeback+0x8e7/0xa50
[ 65.562986][ T12] ? __folio_start_writeback+0x8e9/0xa50
[ 65.568617][ T12] handle_bug+0x84/0x160
[ 65.572849][ T12] exc_invalid_op+0x1a/0x50
[ 65.577343][ T12] asm_exc_invalid_op+0x1a/0x20
[ 65.582179][ T12] RIP: 0010:__folio_start_writeback+0x8e7/0xa50
[ 65.588412][ T12] 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
[ 65.608035][ T12] RSP: 0018:ffffc90000116ea0 EFLAGS: 00010293
[ 65.614229][ T12] RAX: ffffffff81fad086 RBX: ffffea000092b480 RCX: ffff88801d2a5a00
[ 65.622369][ T12] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[ 65.630340][ T12] RBP: ffffc90000117010 R08: ffffc90000116f97 R09: 0000000000000000
[ 65.638297][ T12] R10: ffffc90000116f80 R11: fffff52000022df3 R12: ffffea000092b488
[ 65.646269][ T12] R13: 0000000000000000 R14: ffff888148c9cd80 R15: ffff888148c9cb60
[ 65.654534][ T12] ? __folio_start_writeback+0x8e6/0xa50
[ 65.660366][ T12] ? __pfx___folio_start_writeback+0x10/0x10
[ 65.666343][ T12] ? __pfx_folio_clear_dirty_for_io+0x10/0x10
[ 65.672402][ T12] ? stack_trace_save+0x9c/0xe0
[ 65.677246][ T12] __block_write_full_folio+0x75f/0xe10
[ 65.682785][ T12] ? __pfx_blkdev_get_block+0x10/0x10
[ 65.688322][ T12] blkdev_writepages+0xd1/0x170
[ 65.693167][ T12] ? __pfx_blkdev_writepages+0x10/0x10
[ 65.698627][ T12] ? __pfx_blkdev_writepages+0x10/0x10
[ 65.704156][ T12] do_writepages+0x32b/0x550
[ 65.708841][ T12] __writeback_single_inode+0x145/0xff0
[ 65.714399][ T12] ? wbc_attach_and_unlock_inode+0x3f0/0x5d0
[ 65.720485][ T12] writeback_sb_inodes+0x6c7/0x1010
[ 65.725713][ T12] ? __pfx_writeback_sb_inodes+0x10/0x10
[ 65.731410][ T12] ? __pfx_down_read_trylock+0x10/0x10
[ 65.736874][ T12] ? __pfx___up_read+0x10/0x10
[ 65.741644][ T12] __writeback_inodes_wb+0x111/0x240
[ 65.747014][ T12] wb_writeback+0x44f/0xaf0
[ 65.751521][ T12] ? queue_io+0x3d1/0x590
[ 65.755845][ T12] ? __pfx_wb_writeback+0x10/0x10
[ 65.760871][ T12] wb_workfn+0xaef/0xef0
[ 65.765122][ T12] ? __pfx_wb_workfn+0x10/0x10
[ 65.769888][ T12] ? __lock_acquire+0xab9/0xd20
[ 65.774736][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 65.780467][ T12] ? _raw_spin_unlock_irq+0x23/0x50
[ 65.785671][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 65.791399][ T12] ? process_scheduled_works+0x9ef/0x17b0
[ 65.797122][ T12] process_scheduled_works+0xade/0x17b0
[ 65.802858][ T12] ? __pfx_process_scheduled_works+0x10/0x10
[ 65.808855][ T12] worker_thread+0x8a0/0xda0
[ 65.813539][ T12] kthread+0x70e/0x8a0
[ 65.817603][ T12] ? __pfx_worker_thread+0x10/0x10
[ 65.822698][ T12] ? __pfx_kthread+0x10/0x10
[ 65.827288][ T12] ? _raw_spin_unlock_irq+0x23/0x50
[ 65.832557][ T12] ? lockdep_hardirqs_on+0x9c/0x150
[ 65.837738][ T12] ? __pfx_kthread+0x10/0x10
[ 65.842316][ T12] ret_from_fork+0x47c/0x820
[ 65.846904][ T12] ? __pfx_ret_from_fork+0x10/0x10
[ 65.852010][ T12] ? __switch_to_asm+0x39/0x70
[ 65.856766][ T12] ? __switch_to_asm+0x33/0x70
[ 65.861515][ T12] ? __pfx_kthread+0x10/0x10
[ 65.866180][ T12] ret_from_fork_asm+0x1a/0x30
[ 65.870956][ T12]
[ 65.874414][ T12] Kernel Offset: disabled
[ 65.878820][ T12] Rebooting in 86400 seconds..