What system call signals in Linux can be automatically rejected by the process upon its termination or in other cases?

In Linux, some signals can be automatically ignored by the process, especially during its termination or in certain states. For example:

• SIGCHLD — a signal about the termination of a child process, usually ignored to avoid zombie processes.
• SIGURG — a signal indicating urgent data on a socket, often ignored if not explicitly handled.

Additionally, signals SIGKILL and SIGSTOP cannot be caught or ignored, while other signals can be handled or ignored programmatically.

When a process terminates, the kernel automatically cleans up resources and does not require explicit handling of most signals, so some of them are simply not delivered.