================================================================================ UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dtree.c:3688:8 index -1 is out of range for type 'struct dtslot[128]' CPU: 0 PID: 5905 Comm: syz.2.10 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106 ubsan_epilogue+0xa/0x30 lib/ubsan.c:217 __ubsan_handle_out_of_bounds+0xe3/0xf0 lib/ubsan.c:348 dtInsertEntry+0x93b/0x13e0 fs/jfs/jfs_dtree.c:3688 dtSplitPage+0x2a66/0x3b10 fs/jfs/jfs_dtree.c:1596 dtSplitUp fs/jfs/jfs_dtree.c:1092 [inline] dtInsert+0x108f/0x5f40 fs/jfs/jfs_dtree.c:871 jfs_create+0x6a1/0xa40 fs/jfs/namei.c:137 lookup_open fs/namei.c:3496 [inline] open_last_lookups fs/namei.c:3564 [inline] path_openat+0x1277/0x3190 fs/namei.c:3794 do_filp_open+0x1c5/0x3d0 fs/namei.c:3824 do_sys_openat2+0x12c/0x1c0 fs/open.c:1421 do_sys_open fs/open.c:1436 [inline] __do_sys_openat fs/open.c:1452 [inline] __se_sys_openat fs/open.c:1447 [inline] __x64_sys_openat+0x139/0x160 fs/open.c:1447 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f079eb8f749 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:00007f079cdf6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f079ede5fa0 RCX: 00007f079eb8f749 RDX: 0000000000161042 RSI: 0000200000000040 RDI: ffffffffffffff9c RBP: 00007f079ec13f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f079ede6038 R14: 00007f079ede5fa0 R15: 00007ffe0ba58c38 ================================================================================