syzbot

loop0: detected capacity change from 0 to 32768
UFO tlock:0xffffc900034e2120
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]
CPU: 0 UID: 0 PID: 6081 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:txLog fs/jfs/jfs_txnmgr.c:1390 [inline]
RIP: 0010:txCommit+0xb11/0x5410 fs/jfs/jfs_txnmgr.c:1265
Code: 3c 10 00 74 12 4c 89 f7 e8 2c 5d d6 fe 48 ba 00 00 00 00 00 fc ff df 4c 89 74 24 60 4d 8b 36 4d 8d 7e 28 4c 89 f8 48 c1 e8 03 <80> 3c 10 00 74 12 4c 89 ff e8 01 5d d6 fe 48 ba 00 00 00 00 00 fc
RSP: 0018:ffffc900040af900 EFLAGS: 00010206
RAX: 0000000000000005 RBX: 0000000000000948 RCX: 1ffff9200069cd48
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900040afad0 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1ed4637 R12: 0000000000000002
R13: ffffc900034e2000 R14: 0000000000000000 R15: 0000000000000028
FS:  0000555588eaa500(0000) GS:ffff888126340000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5cf1628000 CR3: 00000000376a8000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 jfs_symlink+0xd03/0xfd0 fs/jfs/namei.c:1041
 vfs_symlink+0x195/0x340 fs/namei.c:5615
 filename_symlinkat+0x1cd/0x420 fs/namei.c:5640
 __do_sys_symlinkat fs/namei.c:5660 [inline]
 __se_sys_symlinkat+0x4e/0x2b0 fs/namei.c:5655
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0fc67ec799
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc12609df8 EFLAGS: 00000246 ORIG_RAX: 000000000000010a
RAX: ffffffffffffffda RBX: 00007f0fc6a65fa0 RCX: 00007f0fc67ec799
RDX: 0000200000000980 RSI: ffffffffffffff9c RDI: 0000200000000440
RBP: 00007f0fc6882bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0fc6a65fac R14: 00007f0fc6a65fa0 R15: 00007f0fc6a65fa0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:txLog fs/jfs/jfs_txnmgr.c:1390 [inline]
RIP: 0010:txCommit+0xb11/0x5410 fs/jfs/jfs_txnmgr.c:1265
Code: 3c 10 00 74 12 4c 89 f7 e8 2c 5d d6 fe 48 ba 00 00 00 00 00 fc ff df 4c 89 74 24 60 4d 8b 36 4d 8d 7e 28 4c 89 f8 48 c1 e8 03 <80> 3c 10 00 74 12 4c 89 ff e8 01 5d d6 fe 48 ba 00 00 00 00 00 fc
RSP: 0018:ffffc900040af900 EFLAGS: 00010206
RAX: 0000000000000005 RBX: 0000000000000948 RCX: 1ffff9200069cd48
RDX: dffffc0000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc900040afad0 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1ed4637 R12: 0000000000000002
R13: ffffc900034e2000 R14: 0000000000000000 R15: 0000000000000028
FS:  0000555588eaa500(0000) GS:ffff888126340000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f5cf1628000 CR3: 00000000376a8000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	3c 10                	cmp    $0x10,%al
   2:	00 74 12 4c          	add    %dh,0x4c(%rdx,%rdx,1)
   6:	89 f7                	mov    %esi,%edi
   8:	e8 2c 5d d6 fe       	call   0xfed65d39
   d:	48 ba 00 00 00 00 00 	movabs $0xdffffc0000000000,%rdx
  14:	fc ff df
  17:	4c 89 74 24 60       	mov    %r14,0x60(%rsp)
  1c:	4d 8b 36             	mov    (%r14),%r14
  1f:	4d 8d 7e 28          	lea    0x28(%r14),%r15
  23:	4c 89 f8             	mov    %r15,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	80 3c 10 00          	cmpb   $0x0,(%rax,%rdx,1) <-- trapping instruction
  2e:	74 12                	je     0x42
  30:	4c 89 ff             	mov    %r15,%rdi
  33:	e8 01 5d d6 fe       	call   0xfed65d39
  38:	48                   	rex.W
  39:	ba 00 00 00 00       	mov    $0x0,%edx
  3e:	00 fc                	add    %bh,%ah