loop0: detected capacity change from 0 to 32768
 ... Log Wrap ... Log Wrap ... Log Wrap ...
blkno = 0, nblocks = 40
ERROR: (device loop0): dbFree: block to be freed is outside the map
 ... Log Wrap ... Log Wrap ... Log Wrap ...
 ... Log Wrap ... Log Wrap ... Log Wrap ...
 ... Log Wrap ... Log Wrap ... Log Wrap ...
BUG at fs/jfs/jfs_dmap.c:3123 assert(bitno < 32)
------------[ cut here ]------------
kernel BUG at fs/jfs/jfs_dmap.c:3123!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5328 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 04/01/2014
RIP: 0010:dbFindBits+0x19e/0x1a0 fs/jfs/jfs_dmap.c:3123
Code: c7 fd 90 0f 0b e8 e2 38 65 fe 48 c7 c7 20 cf 0b 8c 48 c7 c6 60 cc 0b 8c ba 33 0c 00 00 48 c7 c1 60 d7 0b 8c e8 73 12 c7 fd 90 <0f> 0b 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 41
RSP: 0018:ffffc9000da17330 EFLAGS: 00010246
RAX: 0000000000000030 RBX: 0000000000000000 RCX: 9606c61ed2ba1500
RDX: ffffc9000f7d1000 RSI: 0000000000000768 RDI: 0000000000000769
RBP: 00000000ffffffff R08: ffffc9000da170a7 R09: 1ffff92001b42e14
R10: dffffc0000000000 R11: fffff52001b42e15 R12: 0000000000000001
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000020
FS:  00007efcfaa656c0(0000) GS:ffff88808c87f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000002000 CR3: 0000000012501000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 dbAllocNear+0x244/0x3d0 fs/jfs/jfs_dmap.c:1330
 dbAlloc+0x936/0xba0 fs/jfs/jfs_dmap.c:919
 extBalloc fs/jfs/jfs_extent.c:336 [inline]
 extAlloc+0x57d/0x1020 fs/jfs/jfs_extent.c:127
 jfs_get_block+0x358/0xad0 fs/jfs/inode.c:254
 __block_write_begin_int+0x6c6/0x1910 fs/buffer.c:2042
 block_write_begin+0x8d/0x120 fs/buffer.c:2153
 jfs_write_begin+0x35/0x80 fs/jfs/inode.c:306
 generic_perform_write+0x2e2/0x8f0 mm/filemap.c:4325
 generic_file_write_iter+0x14a/0x680 mm/filemap.c:4468
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x61d/0xb90 fs/read_write.c:688
 ksys_write+0x150/0x270 fs/read_write.c:740
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7efcf9b9ce59
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:00007efcfaa64fe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007efcf9e15fa0 RCX: 00007efcf9b9ce59
RDX: 0000000000001006 RSI: 0000200000001440 RDI: 000000000000000a
RBP: 00007efcf9c32d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007efcf9e16038 R14: 00007efcf9e15fa0 R15: 00007ffe3a6aa698
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:dbFindBits+0x19e/0x1a0 fs/jfs/jfs_dmap.c:3123
Code: c7 fd 90 0f 0b e8 e2 38 65 fe 48 c7 c7 20 cf 0b 8c 48 c7 c6 60 cc 0b 8c ba 33 0c 00 00 48 c7 c1 60 d7 0b 8c e8 73 12 c7 fd 90 <0f> 0b 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 41 57 41
RSP: 0018:ffffc9000da17330 EFLAGS: 00010246
RAX: 0000000000000030 RBX: 0000000000000000 RCX: 9606c61ed2ba1500
RDX: ffffc9000f7d1000 RSI: 0000000000000768 RDI: 0000000000000769
RBP: 00000000ffffffff R08: ffffc9000da170a7 R09: 1ffff92001b42e14
R10: dffffc0000000000 R11: fffff52001b42e15 R12: 0000000000000001
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000020
FS:  00007efcfaa656c0(0000) GS:ffff88808c87f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000002000 CR3: 0000000012501000 CR4: 0000000000352ef0