syzbot

 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Kernel panic - not syncing: kernel: panic_on_warn set ...
CPU: 1 UID: 0 PID: 1150 Comm: kworker/u8:6 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)
Call Trace:
 <TASK>
 dump_stack_lvl+0x99/0x250 lib/dump_stack.c:120
 vpanic+0x281/0x750 kernel/panic.c:435
 panic+0xb9/0xc0 kernel/panic.c:571
 check_panic_on_warn kernel/panic.c:328 [inline]
 __warn+0x334/0x4c0 kernel/panic.c:844
 __report_bug lib/bug.c:195 [inline]
 report_bug+0x2be/0x4f0 lib/bug.c:215
 handle_bug+0x84/0x160 arch/x86/kernel/traps.c:338
 exc_invalid_op+0x1a/0x50 arch/x86/kernel/traps.c:392
 asm_exc_invalid_op+0x1a/0x20 arch/x86/include/asm/idtentry.h:616
RIP: 0010:inode_to_wb include/linux/backing-dev.h:239 [inline]
RIP: 0010:__folio_start_writeback+0x9d5/0xb70 mm/page-writeback.c:3027
Code: 28 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 2e a2 29 00 49 8b 07 25 ff 3f 00 00 e9 1b fa ff ff e8 6c 04 c6 ff 90 <0f> 0b 90 e9 d6 fb ff ff e8 5e 04 c6 ff 48 c7 c7 20 fc 5f 8e 4c 89
RSP: 0018:ffffc900040f6ea0 EFLAGS: 00010293
RAX: ffffffff81fadbd4 RBX: ffffea0000930e40 RCX: ffff888026e78000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900040f7010 R08: ffffc900040f6f97 R09: 0000000000000000
R10: ffffc900040f6f80 R11: fffff5200081edf3 R12: ffffea0000930e48
R13: 0000000000000000 R14: ffff888148ca6480 R15: ffff888148ca6260
 __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+0xae1/0x17b0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x711/0x8a0 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>
Kernel Offset: disabled
Rebooting in 86400 seconds..