 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x439/0x7d0
 ret_from_fork_asm+0x1a/0x30
------------[ cut here ]------------
kernel BUG at mm/filemap.c:3475!
Oops: invalid opcode: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 20443 Comm: syz.0.19389 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:filemap_fault+0x117d/0x1200
Code: 38 c1 0f 8c 8e fc ff ff 4c 89 e7 e8 8d d4 2b 00 e9 81 fc ff ff e8 13 62 c8 ff 48 89 df 48 c7 c6 a0 37 94 8b e8 b4 a0 30 ff 90 <0f> 0b e8 fc 61 c8 ff 48 8b 3c 24 48 c7 c6 20 3e 94 8b e8 9c a0 30
RSP: 0018:ffffc900076bf7a0 EFLAGS: 00010246
RAX: d438c2c178051700 RBX: ffffea0004ac3e00 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8d9b9e62 RDI: 00000000ffffffff
RBP: ffffc900076bf8d8 R08: ffffffff8fa3a537 R09: 1ffffffff1f474a6
R10: dffffc0000000000 R11: fffffbfff1f474a7 R12: dffffc0000000000
R13: 1ffffd40009587c1 R14: ffffea0004ac3e18 R15: ffffea0004ac3e08
FS:  00007fa8eb4026c0(0000) GS:ffff8880b8615000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7ce373a440 CR3: 000000012e2ca000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 __do_fault+0x138/0x390
 __handle_mm_fault+0x3611/0x5440
 handle_mm_fault+0x40a/0x8e0
 do_user_addr_fault+0x764/0x1390
 exc_page_fault+0x76/0xf0
 asm_exc_page_fault+0x26/0x30
RIP: 0010:strncpy_from_user+0xb7/0x290
Code: 00 00 4c 89 f6 e8 09 97 c0 fc 49 83 fe 07 0f 86 9d 00 00 00 48 89 1c 24 4c 89 74 24 08 48 c7 c5 f8 ff ff ff 45 31 e4 4c 89 fb <4f> 8b 34 27 48 b8 ff fe fe fe fe fe fe fe 4d 8d 3c 06 4d 89 f5 49
RSP: 0018:ffffc900076bfd30 EFLAGS: 00010246
RAX: ffffffff84ff2b37 RBX: 00002000000001c0 RCX: ffff88811edc8000
RDX: 0000000000000000 RSI: 0000000000000fe0 RDI: 0000000000000007
RBP: fffffffffffffff8 R08: ffff8880342cf5ff R09: 1ffff11006859ebf
R10: dffffc0000000000 R11: ffffed1006859ec0 R12: 0000000000000000
R13: dffffc0000000000 R14: 0000000000000fe0 R15: 00002000000001c0
 getname_flags+0xf3/0x540
 do_sys_openat2+0xbc/0x1c0
 __x64_sys_openat+0x138/0x170
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa8ea58eba9
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:00007fa8eb402038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fa8ea7d5fa0 RCX: 00007fa8ea58eba9
RDX: 0000000000060040 RSI: 00002000000001c0 RDI: ffffffffffffff9c
RBP: 00007fa8ea611e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa8ea7d6038 R14: 00007fa8ea7d5fa0 R15: 00007ffeb538b888
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:filemap_fault+0x117d/0x1200
Code: 38 c1 0f 8c 8e fc ff ff 4c 89 e7 e8 8d d4 2b 00 e9 81 fc ff ff e8 13 62 c8 ff 48 89 df 48 c7 c6 a0 37 94 8b e8 b4 a0 30 ff 90 <0f> 0b e8 fc 61 c8 ff 48 8b 3c 24 48 c7 c6 20 3e 94 8b e8 9c a0 30
RSP: 0018:ffffc900076bf7a0 EFLAGS: 00010246
RAX: d438c2c178051700 RBX: ffffea0004ac3e00 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8d9b9e62 RDI: 00000000ffffffff
RBP: ffffc900076bf8d8 R08: ffffffff8fa3a537 R09: 1ffffffff1f474a6
R10: dffffc0000000000 R11: fffffbfff1f474a7 R12: dffffc0000000000
R13: 1ffffd40009587c1 R14: ffffea0004ac3e18 R15: ffffea0004ac3e08
FS:  00007fa8eb4026c0(0000) GS:ffff8880b8615000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c38de6b CR3: 000000012e2ca000 CR4: 00000000000006f0
