loop0: detected capacity change from 0 to 32768
lmLogOpen: exit(-6)
ERROR: (device loop0): txBegin: read-only filesystem
ERROR: (device loop0): remounting filesystem as read-only
jfs_dirty_inode called on read-only volume
Is remount racy?
find_entry called with index = 0
find_entry called with index = 0
find_entry called with index = 0
find_entry called with index = 0
jfs_dirty_inode called on read-only volume
Is remount racy?
jfs_dirty_inode called on read-only volume
Is remount racy?
Oops: general protection fault, probably for non-canonical address 0xdffffc00000000c7: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000638-0x000000000000063f]
CPU: 0 UID: 0 PID: 5325 Comm: syz.0.0 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:JFS_SBI fs/jfs/jfs_incore.h:217 [inline]
RIP: 0010:txEnd+0xb4/0x530 fs/jfs/jfs_txnmgr.c:507
Code: 49 8d 5e 20 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 bc 8f de fe 41 bf 38 06 00 00 4c 03 3b 4c 89 f8 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 ff e8 9d 8f de fe 49 8b 1f 48 83 c3 30
RSP: 0018:ffffc9000fbafb00 EFLAGS: 00010202
RAX: 00000000000000c7 RBX: ffffc900013a9020 RCX: 0000000000000000
RDX: 0000000000000006 RSI: ffffffff8d7eb452 RDI: 00000000ffffffff
RBP: ffffc9000fbafd90 R08: ffffffff8f9e2f77 R09: 1ffffffff1f3c5ee
R10: dffffc0000000000 R11: fffffbfff1f3c5ef R12: ffff888042d29be8
R13: dffffc0000000000 R14: ffffc900013a9000 R15: 0000000000000638
FS:  00007fbc517ba6c0(0000) GS:ffff88808d306000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000425ce000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 jfs_mkdir+0x344/0xa70 fs/jfs/namei.c:293
 vfs_mkdir+0x303/0x510 fs/namei.c:4453
 do_mkdirat+0x247/0x590 fs/namei.c:4486
 __do_sys_mkdirat fs/namei.c:4503 [inline]
 __se_sys_mkdirat fs/namei.c:4501 [inline]
 __x64_sys_mkdirat+0x87/0xa0 fs/namei.c:4501
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbc5098d617
Code: 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 02 01 00 00 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:00007fbc517b9e68 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007fbc517b9ef0 RCX: 00007fbc5098d617
RDX: 00000000000001ff RSI: 00002000000006c0 RDI: 00000000ffffff9c
RBP: 0000200000000680 R08: 0000000000000000 R09: 0000000000000000
R10: 0000200000000680 R11: 0000000000000246 R12: 00002000000006c0
R13: 00007fbc517b9eb0 R14: 0000000000000000 R15: 0000200000000700
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:JFS_SBI fs/jfs/jfs_incore.h:217 [inline]
RIP: 0010:txEnd+0xb4/0x530 fs/jfs/jfs_txnmgr.c:507
Code: 49 8d 5e 20 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 bc 8f de fe 41 bf 38 06 00 00 4c 03 3b 4c 89 f8 48 c1 e8 03 <42> 80 3c 28 00 74 08 4c 89 ff e8 9d 8f de fe 49 8b 1f 48 83 c3 30
RSP: 0018:ffffc9000fbafb00 EFLAGS: 00010202
RAX: 00000000000000c7 RBX: ffffc900013a9020 RCX: 0000000000000000
RDX: 0000000000000006 RSI: ffffffff8d7eb452 RDI: 00000000ffffffff
RBP: ffffc9000fbafd90 R08: ffffffff8f9e2f77 R09: 1ffffffff1f3c5ee
R10: dffffc0000000000 R11: fffffbfff1f3c5ef R12: ffff888042d29be8
R13: dffffc0000000000 R14: ffffc900013a9000 R15: 0000000000000638
FS:  00007fbc517ba6c0(0000) GS:ffff88808d306000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 00000000425ce000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess):
   0:	49 8d 5e 20          	lea    0x20(%r14),%rbx
   4:	48 89 d8             	mov    %rbx,%rax
   7:	48 c1 e8 03          	shr    $0x3,%rax
   b:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1)
  10:	74 08                	je     0x1a
  12:	48 89 df             	mov    %rbx,%rdi
  15:	e8 bc 8f de fe       	call   0xfede8fd6
  1a:	41 bf 38 06 00 00    	mov    $0x638,%r15d
  20:	4c 03 3b             	add    (%rbx),%r15
  23:	4c 89 f8             	mov    %r15,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	4c 89 ff             	mov    %r15,%rdi
  34:	e8 9d 8f de fe       	call   0xfede8fd6
  39:	49 8b 1f             	mov    (%r15),%rbx
  3c:	48 83 c3 30          	add    $0x30,%rbx