The following warning information applies to the use of MDB.
The debugger and its dmods execute in the same address space, and thus it is quite possible that a buggy dmod can cause MDB to dump core or otherwise misbehave. The MDB resume capability, described in Signal Handling, provides a limited recovery mechanism for these situations. However, it is not possible for MDB to know definitively whether the dmod in question has corrupted only its own state, or the debugger's global state. Therefore a resume operation cannot be guaranteed to be safe, or to prevent a subsequent crash of the debugger. The safest course of action following a resume is to save any important debug information, and then quit and restart the debugger.
The use of the debugger to modify (that is, write to) the address space of live running operating system is extremely dangerous, and may result in a system panic in the event the user damages a kernel data structure.
The use of kmdb to stop the live operating system using mdb -K or by setting a breakpoint in the live operating system is intended for use by developers and not on production systems. When the operating system kernel is stopped by kmdb, operating system services and networking are not executing, and other systems on the network that depend upon the target system will not be able to contact the target system.