------------[ cut here ]------------ WARNING: ./include/linux/backing-dev.h:243 at inode_to_wb include/linux/backing-dev.h:239 [inline], CPU#0: kworker/u8:4/60 WARNING: ./include/linux/backing-dev.h:243 at __folio_start_writeback+0x8e7/0xa50 mm/page-writeback.c:3033, CPU#0: kworker/u8:4/60 Modules linked in: CPU: 0 UID: 0 PID: 60 Comm: kworker/u8:4 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Workqueue: writeback wb_workfn (flush-8:0) RIP: 0010:inode_to_wb include/linux/backing-dev.h:239 [inline] RIP: 0010:__folio_start_writeback+0x8e7/0xa50 mm/page-writeback.c:3033 Code: 8b 05 2d 87 eb 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 e9 10 8d 8f 09 cc e8 1a fa c5 ff 90 <0f> 0b 90 e9 e5 fb ff ff e8 0c fa c5 ff 48 c7 c7 20 ff 5f 8e 4c 89 RSP: 0018:ffffc9000211eea0 EFLAGS: 00010293 RAX: ffffffff81faf916 RBX: ffffea0000932780 RCX: ffff88801c3c5a00 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9000211f010 R08: ffffc9000211ef97 R09: 0000000000000000 R10: ffffc9000211ef80 R11: fffff52000423df3 R12: ffffea0000932788 R13: 0000000000000000 R14: ffff888023017000 R15: ffff888023016de0 FS: 0000000000000000(0000) GS:ffff8881257b8000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005581d9aeef70 CR3: 000000007b9c8000 CR4: 00000000003526f0 Call Trace: __block_write_full_folio+0x75f/0xe10 fs/buffer.c:1928 blkdev_writepages+0xd1/0x170 block/fops.c:484 do_writepages+0x32e/0x550 mm/page-writeback.c:2604 __writeback_single_inode+0x145/0xff0 fs/fs-writeback.c:1680 writeback_sb_inodes+0x6c7/0x1010 fs/fs-writeback.c:1976 __writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2047 wb_writeback+0x44f/0xaf0 fs/fs-writeback.c:2158 wb_check_old_data_flush fs/fs-writeback.c:2262 [inline] wb_do_writeback fs/fs-writeback.c:2315 [inline] wb_workfn+0xaef/0xef0 fs/fs-writeback.c:2343 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3319 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x47c/0x820 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245