BSD syscall#535
svc · unix #535
objc_bp_assist_cfg_np
Configures kernel-assisted Objective-C breakpoint trampolines for the calling process.
Prototype
int objc_bp_assist_cfg_np(uint64_t adr, uint64_t ctl);Returns: int
Arguments
| Name | Type | Dir | Description |
|---|---|---|---|
| adr | uint64_t | - | |
| ctl | uint64_t | - |
Version history
| XNU tag | macOS | # |
|---|---|---|
| xnu-11215.1.10 | macOS 15.0 Sequoia | 535 |
| xnu-11417.101.15 | macOS 15.4 Sequoia | 535 |
| xnu-12377.1.9 | macOS 26.0 Tahoe | 535 |
| xnu-11215.41.3 | — | 535 |
| xnu-11215.61.5 | — | 535 |
| xnu-11215.81.4 | — | 535 |
| xnu-11417.121.6 | — | 535 |
| xnu-11417.140.69 | — | 535 |
| xnu-12377.101.15 | — | 535 |
| xnu-12377.41.6 | — | 535 |
| xnu-12377.61.12 | — | 535 |
| xnu-12377.81.4 | — | 535 |
Notes
Added in macOS 12 / iOS 15 to support faster objc_msgSend breakpoint dispatch in lldb: the syscall registers a small per-process configuration (address ranges, hit counts) that the kernel uses when the runtime traps. Outside of lldb and Xcode's debugserver the call has essentially no users. The np suffix marks it as non-portable Apple-only API.
Detection
Any successful call from a process whose parent is not debugserver / lldb-rpc-server is worth investigating — debugger-attach is implied. ES_EVENT_TYPE_NOTIFY_GET_TASK on the same target provides corroborating evidence.
Related APIs
task_for_pidptracethread_set_stateobjc_msgSend