loop0: detected capacity change from 0 to 32768
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BUG at fs/jfs/jfs_dmap.c:3036 assert(bitno < 32)
------------[ cut here ]------------
kernel BUG at fs/jfs/jfs_dmap.c:3036!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5337 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:dbFindBits+0x19e/0x1a0 fs/jfs/jfs_dmap.c:3036
Code: dd fd 90 0f 0b e8 e2 6e 77 fe 48 c7 c7 20 62 c5 8b 48 c7 c6 60 5f c5 8b ba dc 0b 00 00 48 c7 c1 20 6a c5 8b e8 c3 58 dd 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:ffffc9000e6ef330 EFLAGS: 00010246
RAX: 0000000000000030 RBX: 0000000000000000 RCX: a9c0f41a8bd2d200
RDX: ffffc90020d92000 RSI: 0000000000004d0b RDI: 0000000000004d0c
RBP: 00000000ffffffff R08: ffff88801fc247d3 R09: 1ffff11003f848fa
R10: dffffc0000000000 R11: ffffed1003f848fb R12: 0000000000000001
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000020
FS:  00007f6963a8c6c0(0000) GS:ffff88808d22f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001000 CR3: 000000003621d000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 dbAllocNear+0x244/0x3d0 fs/jfs/jfs_dmap.c:1243
 dbAlloc+0x933/0xba0 fs/jfs/jfs_dmap.c:832
 extBalloc fs/jfs/jfs_extent.c:336 [inline]
 extAlloc+0x54a/0xfb0 fs/jfs/jfs_extent.c:127
 jfs_get_block+0x346/0xab0 fs/jfs/inode.c:254
 __block_write_begin_int+0x6b5/0x1900 fs/buffer.c:2145
 block_write_begin+0x8d/0x120 fs/buffer.c:2256
 jfs_write_begin+0x35/0x80 fs/jfs/inode.c:306
 generic_perform_write+0x2c5/0x900 mm/filemap.c:4314
 generic_file_write_iter+0x117/0x550 mm/filemap.c:4457
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0x5c9/0xb30 fs/read_write.c:686
 ksys_pwrite64 fs/read_write.c:793 [inline]
 __do_sys_pwrite64 fs/read_write.c:801 [inline]
 __se_sys_pwrite64 fs/read_write.c:798 [inline]
 __x64_sys_pwrite64+0x193/0x220 fs/read_write.c:798
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6962b8f7c9
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:00007f6963a8c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 00007f6962de5fa0 RCX: 00007f6962b8f7c9
RDX: 000000000000fdef RSI: 0000200000000140 RDI: 0000000000000009
RBP: 00007f6962c13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000fecc R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6962de6038 R14: 00007f6962de5fa0 R15: 00007ffc0ec42858
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:dbFindBits+0x19e/0x1a0 fs/jfs/jfs_dmap.c:3036
Code: dd fd 90 0f 0b e8 e2 6e 77 fe 48 c7 c7 20 62 c5 8b 48 c7 c6 60 5f c5 8b ba dc 0b 00 00 48 c7 c1 20 6a c5 8b e8 c3 58 dd 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:ffffc9000e6ef330 EFLAGS: 00010246
RAX: 0000000000000030 RBX: 0000000000000000 RCX: a9c0f41a8bd2d200
RDX: ffffc90020d92000 RSI: 0000000000004d0b RDI: 0000000000004d0c
RBP: 00000000ffffffff R08: ffff88801fc247d3 R09: 1ffff11003f848fa
R10: dffffc0000000000 R11: ffffed1003f848fb R12: 0000000000000001
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000020
FS:  00007f6963a8c6c0(0000) GS:ffff88808d22f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000001000 CR3: 000000003621d000 CR4: 0000000000352ef0