------------[ cut here ]------------ UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dtree.c:784:21 index -1 is out of range for type 'struct dtslot[128]' CPU: 0 UID: 0 PID: 5335 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: 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 dtSearch+0x1a66/0x21b0 fs/jfs/jfs_dtree.c:784 jfs_lookup+0x155/0x380 fs/jfs/namei.c:1461 lookup_one_qstr_excl+0x131/0x360 fs/namei.c:1747 __start_dirop fs/namei.c:2866 [inline] start_dirop fs/namei.c:2875 [inline] filename_create+0x209/0x360 fs/namei.c:4879 do_symlinkat+0x120/0x3c0 fs/namei.c:5534 __do_sys_symlinkat fs/namei.c:5562 [inline] __se_sys_symlinkat fs/namei.c:5559 [inline] __x64_sys_symlinkat+0x95/0xb0 fs/namei.c:5559 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: 0033:0x7fbb8198f7c9 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:00007fbb82774038 EFLAGS: 00000246 ORIG_RAX: 000000000000010a RAX: ffffffffffffffda RBX: 00007fbb81be6090 RCX: 00007fbb8198f7c9 RDX: 0000200000000200 RSI: ffffffffffffff9c RDI: 00002000000003c0 RBP: 00007fbb81a13f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fbb81be6128 R14: 00007fbb81be6090 R15: 00007ffe61c6d7c8 ---[ end trace ]---