loop0: detected capacity change from 32768 to 32767
ERROR: (device loop0): dbAllocNext: Corrupt dmap page
ERROR: (device loop0): remounting filesystem as read-only
------------[ cut here ]------------
UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dmap.c:2780:24
index 4278910730 is out of range for type 's8[1365]' (aka 'signed char[1365]')
CPU: 0 UID: 0 PID: 5348 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
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 ubsan_epilogue+0xa/0x40 lib/ubsan.c:233
 __ubsan_handle_out_of_bounds+0xe9/0xf0 lib/ubsan.c:455
 dbJoin+0x29f/0x300 fs/jfs/jfs_dmap.c:2780
 dbFreeBits+0x4e1/0xdb0 fs/jfs/jfs_dmap.c:2340
 dbFreeDmap fs/jfs/jfs_dmap.c:2089 [inline]
 dbFree+0x336/0x650 fs/jfs/jfs_dmap.c:398
 txFreeMap+0xb90/0xde0 fs/jfs/jfs_txnmgr.c:2525
 jfs_free_zero_link+0x21f/0x4a0 fs/jfs/namei.c:730
 jfs_evict_inode+0x363/0x440 fs/jfs/inode.c:159
 evict+0x5f4/0xae0 fs/inode.c:837
 __dentry_kill+0x209/0x660 fs/dcache.c:670
 shrink_kill+0xa9/0x2c0 fs/dcache.c:1137
 shrink_dentry_list+0x2e0/0x5e0 fs/dcache.c:1164
 shrink_dcache_sb+0x218/0x3a0 fs/dcache.c:1285
 reconfigure_super+0x4fb/0x880 fs/super.c:1055
 do_remount fs/namespace.c:3264 [inline]
 path_mount+0xd29/0xff0 fs/namespace.c:4014
 do_mount fs/namespace.c:4035 [inline]
 __do_sys_mount fs/namespace.c:4224 [inline]
 __se_sys_mount+0x313/0x410 fs/namespace.c:4201
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe12eb8f7c9
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:00007fe12aff5038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fe12ede6090 RCX: 00007fe12eb8f7c9
RDX: 0000000000000000 RSI: 00002000000001c0 RDI: 0000000000000000
RBP: 00007fe12ec13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000010f4c2a R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe12ede6128 R14: 00007fe12ede6090 R15: 00007ffc03531208
 </TASK>
---[ end trace ]---