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linuxposixsegmentation-faultcoredump

What is SEGV_MAPERR?

What is SEGV_MAPERR, why does it always come up with SIGSEGV?

Solution

  • There are two common kinds of SEGV, which is an error that results from an invalid memory access:

    1. A page was accessed which had the wrong permissions. E.g., it was read-only but your code tried to write to it. This will be reported as SEGV_ACCERR.
    2. A page was accessed that is not even mapped into the address space of the application at all. This will often result from dereferencing a null pointer or a pointer that was corrupted with a small integer value. This is reported as SEGV_MAPERR.

    Documentation of a sort (indexed Linux source code) for SEGV_MAPERR is here: https://elixir.bootlin.com/linux/latest/A/ident/SEGV_MAPERR.