syzbot

 __dentry_kill+0x1d0/0x600 fs/dcache.c:669
 dput.part.0+0x4b1/0x9b0 fs/dcache.c:911
 dput fs/dcache.c:901 [inline]
 do_one_tree fs/dcache.c:1607 [inline]
 shrink_dcache_for_umount+0x159/0x3e0 fs/dcache.c:1621
 generic_shutdown_super+0x6c/0x390 fs/super.c:621
 kill_anon_super+0x3a/0x60 fs/super.c:1282
------------[ cut here ]------------
kernel BUG at mm/filemap.c:1498!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 6099 Comm: syz.0.99 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:folio_unlock mm/filemap.c:1498 [inline]
RIP: 0010:folio_unlock+0xb3/0xd0 mm/filemap.c:1493
Code: b3 5c c9 ff 48 89 ef 31 f6 e8 f9 ed ff ff 5b 5d e9 a2 5c c9 ff e8 9d 5c c9 ff 48 c7 c6 60 19 b9 8b 48 89 ef e8 0e 0d 12 00 90 <0f> 0b 48 89 df e8 d3 bb 2f 00 e9 7b ff ff ff 66 66 2e 0f 1f 84 00
RSP: 0018:ffffc90003887980 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff88807c7d4880 RSI: ffffffff81f231a2 RDI: ffff88807c7d4cc4
RBP: ffffea0001afa3c0 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff90ab5c97 R11: 0000000000000001 R12: ffff888074aadc40
R13: ffffc90003887de8 R14: ffffea0001afa3c0 R15: dffffc0000000000
FS:  000055555fff5500(0000) GS:ffff8881246b8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c00776d000 CR3: 000000007e01f000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 netfs_perform_write+0xacd/0x1e60 fs/netfs/buffered_write.c:407
 netfs_buffered_write_iter_locked fs/netfs/buffered_write.c:452 [inline]
 netfs_file_write_iter+0x495/0x570 fs/netfs/buffered_write.c:491
 v9fs_file_write_iter+0x9b/0x100 fs/9p/vfs_file.c:407
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x7d3/0x11d0 fs/read_write.c:686
 ksys_write+0x12a/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7fd718ebe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffdbc42d438 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f7fd73c5fa0 RCX: 00007f7fd718ebe9
RDX: 0000000000000018 RSI: 0000200000000380 RDI: 0000000000000007
RBP: 00007f7fd7211e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7fd73c5fa0 R14: 00007f7fd73c5fa0 R15: 0000000000000003
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:folio_unlock mm/filemap.c:1498 [inline]
RIP: 0010:folio_unlock+0xb3/0xd0 mm/filemap.c:1493
Code: b3 5c c9 ff 48 89 ef 31 f6 e8 f9 ed ff ff 5b 5d e9 a2 5c c9 ff e8 9d 5c c9 ff 48 c7 c6 60 19 b9 8b 48 89 ef e8 0e 0d 12 00 90 <0f> 0b 48 89 df e8 d3 bb 2f 00 e9 7b ff ff ff 66 66 2e 0f 1f 84 00
RSP: 0018:ffffc90003887980 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff88807c7d4880 RSI: ffffffff81f231a2 RDI: ffff88807c7d4cc4
RBP: ffffea0001afa3c0 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff90ab5c97 R11: 0000000000000001 R12: ffff888074aadc40
R13: ffffc90003887de8 R14: ffffea0001afa3c0 R15: dffffc0000000000
FS:  000055555fff5500(0000) GS:ffff8881247b8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001000 CR3: 000000007e01f000 CR4: 00000000003526f0