loop0: detected capacity change from 0 to 32768
BUG at fs/jfs/jfs_dmap.c:3070 assert(n < 4)
------------[ cut here ]------------
kernel BUG at fs/jfs/jfs_dmap.c:3070!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5315 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:dbFindLeaf+0x519/0x520 fs/jfs/jfs_dmap.c:3070
Code: e9 4e ff ff ff e8 a7 04 5f fe 48 c7 c7 a0 36 2c 8c 48 c7 c6 e0 33 2c 8c ba fe 0b 00 00 48 c7 c1 c0 41 2c 8c e8 48 ab bf fd 90 <0f> 0b 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000e3e7ab0 EFLAGS: 00010246
RAX: 000000000000002b RBX: 0000000000000000 RCX: d38f8c89f3759700
RDX: ffffc9000ec2a000 RSI: 0000000000001a83 RDI: 0000000000001a84
RBP: 0000000000000003 R08: ffffc9000e3e7827 R09: 1ffff92001c7cf04
R10: dffffc0000000000 R11: fffff52001c7cf05 R12: 000000000000000a
R13: 0000000000000005 R14: 0000000000000008 R15: 0000000000000155
FS:  00007fa17c3f56c0(0000) GS:ffff88808c549000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6fa57bd000 CR3: 00000000437da000 CR4: 0000000000352ef0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 00000000000f0602
Call Trace:
 <TASK>
 dbAllocDmapLev+0x60/0x3b0 fs/jfs/jfs_dmap.c:2056
 dbAllocCtl+0x145/0x990 fs/jfs/jfs_dmap.c:1912
 dbAllocAG+0xbbd/0xf80 fs/jfs/jfs_dmap.c:1559
 dbDiscardAG+0x2d6/0x8f0 fs/jfs/jfs_dmap.c:1695
 jfs_ioc_trim+0x433/0x670 fs/jfs/jfs_discard.c:106
 jfs_ioctl+0x28e/0x3b0 fs/jfs/ioctl.c:131
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa17ff9e0d9
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:00007fa17c3f4fe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fa180225fa0 RCX: 00007fa17ff9e0d9
RDX: 00002000000000c0 RSI: 00000000c0185879 RDI: 0000000000000006
RBP: 00007fa180035024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa180226038 R14: 00007fa180225fa0 R15: 00007ffe437f34e8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:dbFindLeaf+0x519/0x520 fs/jfs/jfs_dmap.c:3070
Code: e9 4e ff ff ff e8 a7 04 5f fe 48 c7 c7 a0 36 2c 8c 48 c7 c6 e0 33 2c 8c ba fe 0b 00 00 48 c7 c1 c0 41 2c 8c e8 48 ab bf fd 90 <0f> 0b 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000e3e7ab0 EFLAGS: 00010246
RAX: 000000000000002b RBX: 0000000000000000 RCX: d38f8c89f3759700
RDX: ffffc9000ec2a000 RSI: 0000000000001a83 RDI: 0000000000001a84
RBP: 0000000000000003 R08: ffffc9000e3e7827 R09: 1ffff92001c7cf04
R10: dffffc0000000000 R11: fffff52001c7cf05 R12: 000000000000000a
R13: 0000000000000005 R14: 0000000000000008 R15: 0000000000000155
FS:  00007fa17c3f56c0(0000) GS:ffff88808c549000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa17c3d2f90 CR3: 00000000437da000 CR4: 0000000000352ef0
DR0: 0000200000000300 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 00000000000f0602