arch_do_signal_or_restart+0x8f/0x7d0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop+0x84/0x110 kernel/entry/common.c:40
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
 do_syscall_64+0x41c/0x4e0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
------------[ cut here ]------------
kernel BUG at mm/filemap.c:1498!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 2 UID: 0 PID: 7907 Comm: syz.5.494 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:folio_unlock mm/filemap.c:1498 [inline]
RIP: 0010:folio_unlock+0xb3/0xd0 mm/filemap.c:1493
Code: a3 5d c9 ff 48 89 ef 31 f6 e8 f9 ed ff ff 5b 5d e9 92 5d c9 ff e8 8d 5d c9 ff 48 c7 c6 e0 1b b9 8b 48 89 ef e8 5e 0d 12 00 90 <0f> 0b 48 89 df e8 e3 bc 2f 00 e9 7b ff ff ff 66 66 2e 0f 1f 84 00
RSP: 0018:ffffc900039f7980 EFLAGS: 00010287
RAX: 00000000000320be RBX: 0000000000000000 RCX: ffffc90004b19000
RDX: 0000000000080000 RSI: ffffffff81f24152 RDI: ffff888055742884
RBP: ffffea0001702d00 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff90ab7397 R11: 0000000000000003 R12: ffff88803ca71570
R13: ffffc900039f7de8 R14: ffffea0001702d00 R15: dffffc0000000000
FS:  00007fdeeeb2e6c0(0000) GS:ffff8880d68b3000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6de4985f98 CR3: 000000004ea55000 CR4: 0000000000352ef0
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+0x7d0/0x11d0 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/0x4e0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fdeedd8eba9
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:00007fdeeeb2e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fdeedfd5fa0 RCX: 00007fdeedd8eba9
RDX: 000000000000003c RSI: 0000200000000880 RDI: 000000000000000a
RBP: 00007fdeede11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdeedfd6038 R14: 00007fdeedfd5fa0 R15: 00007fff04c9ff38
 </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: a3 5d c9 ff 48 89 ef 31 f6 e8 f9 ed ff ff 5b 5d e9 92 5d c9 ff e8 8d 5d c9 ff 48 c7 c6 e0 1b b9 8b 48 89 ef e8 5e 0d 12 00 90 <0f> 0b 48 89 df e8 e3 bc 2f 00 e9 7b ff ff ff 66 66 2e 0f 1f 84 00
RSP: 0018:ffffc900039f7980 EFLAGS: 00010287
RAX: 00000000000320be RBX: 0000000000000000 RCX: ffffc90004b19000
RDX: 0000000000080000 RSI: ffffffff81f24152 RDI: ffff888055742884
RBP: ffffea0001702d00 R08: 0000000000000001 R09: 0000000000000001
R10: ffffffff90ab7397 R11: 0000000000000003 R12: ffff88803ca71570
R13: ffffc900039f7de8 R14: ffffea0001702d00 R15: dffffc0000000000
FS:  00007fdeeeb2e6c0(0000) GS:ffff8880d69b3000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000559178ad9b00 CR3: 000000004ea55000 CR4: 0000000000352ef0
DR0: 000000000000a7d0 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400