------------[ cut here ]------------ 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: 7177 Comm: syz.1.199 Not tainted 6.16.0-rc3-syzkaller-00044-g7595b66ae9de #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 ubsan_epilogue+0xa/0x40 lib/ubsan.c:233 __ubsan_handle_out_of_bounds+0xe9/0xf0 lib/ubsan.c:455 dtInsertEntry+0x936/0x1430 fs/jfs/jfs_dtree.c:3700 dtSplitPage+0x2a83/0x3b20 fs/jfs/jfs_dtree.c:1596 dtSplitUp fs/jfs/jfs_dtree.c:1092 [inline] dtInsert+0x109b/0x5f40 fs/jfs/jfs_dtree.c:871 jfs_symlink+0x715/0xe60 fs/jfs/namei.c:1020 vfs_symlink+0x143/0x2f0 fs/namei.c:4739 do_symlinkat+0x1b1/0x3f0 fs/namei.c:4765 __do_sys_symlink fs/namei.c:4786 [inline] __se_sys_symlink fs/namei.c:4784 [inline] __x64_sys_symlink+0x7a/0x90 fs/namei.c:4784 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff1e2f8e929 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:00007ff1e3e4b038 EFLAGS: 00000246 ORIG_RAX: 0000000000000058 RAX: ffffffffffffffda RBX: 00007ff1e31b5fa0 RCX: 00007ff1e2f8e929 RDX: 0000000000000000 RSI: 0000200000000640 RDI: 0000200000000540 RBP: 00007ff1e3010b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007ff1e31b5fa0 R15: 00007ffd4eb00d88 ---[ end trace ]---