syzbot

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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 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
RSP: 0018:ffffc9000211eea0 EFLAGS: 00010293
RAX: ffffffff81fad086 RBX: ffffea00009428c0 RCX: ffff88801c3d8000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000211f010 R08: ffffc9000211ef97 R09: 0000000000000000
R10: ffffc9000211ef80 R11: fffff52000423df3 R12: ffffea00009428c8
R13: 0000000000000000 R14: ffff8880230e9f80 R15: ffff8880230e9d60
FS:  0000000000000000(0000) GS:ffff8881259f7000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055fbf95dc204 CR3: 000000000e138000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __block_write_full_folio+0x75f/0xe10 fs/buffer.c:1928
 blkdev_writepages+0xd1/0x170 block/fops.c:484
 do_writepages+0x32b/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
 </TASK>