syzbot

loop0: detected capacity change from 0 to 32768
 ... Log Wrap ... Log Wrap ... Log Wrap ...
read_mapping_page failed!
ERROR: (device loop0): txCommit: 
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UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dtree.c:3700:8
index -1 is out of range for type 'struct dtslot[128]'
CPU: 1 UID: 0 PID: 6074 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 ubsan_epilogue+0xa/0x30 lib/ubsan.c:233
 __ubsan_handle_out_of_bounds+0xe8/0xf0 lib/ubsan.c:455
 dtInsertEntry+0x936/0x1430 fs/jfs/jfs_dtree.c:3700
 dtSplitPage+0x290b/0x37c0 fs/jfs/jfs_dtree.c:1596
 dtSplitUp fs/jfs/jfs_dtree.c:1092 [inline]
 dtInsert+0x107a/0x5de0 fs/jfs/jfs_dtree.c:871
 jfs_mkdir+0x783/0xb00 fs/jfs/namei.c:270
 vfs_mkdir+0x52c/0x5d0 fs/namei.c:5139
 do_mkdirat+0x281/0x4c0 fs/namei.c:5173
 __do_sys_mkdirat fs/namei.c:5195 [inline]
 __se_sys_mkdirat fs/namei.c:5193 [inline]
 __x64_sys_mkdirat+0x87/0xa0 fs/namei.c:5193
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7febb3dd9b97
Code: 00 66 90 48 89 f2 b9 00 01 00 00 48 89 fe bf 9c ff ff ff e9 db f7 ff ff 66 2e 0f 1f 84 00 00 00 00 00 90 b8 02 01 00 00 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:00007fff3a6059f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000102
RAX: ffffffffffffffda RBX: 00007fff3a605a80 RCX: 00007febb3dd9b97
RDX: 00000000000001ff RSI: 0000200000000540 RDI: 00000000ffffff9c
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000540
R13: 00007fff3a605a40 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
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