What is SEGV_MAPERR?

linux posix segmentation-fault coredump
Geek picture Geek · Jun 16, 2009 · Viewed 75.3k times · Source

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

Answer

ahcox picture ahcox · Jan 23, 2015

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: http://lxr.free-electrons.com/ident?i=SEGV_MAPERR.

Related questions

How to kill all processes with a given partial name?

I want to kill all processes that I get by: ps aux | grep my_pattern How to do it? This does not work: pkill my_pattern

Read More
What is the meaning of "POSIX"?

What is POSIX? I have read the Wikipedia article and I read it every time I encounter the term. The fact is that I never really understood what it is. Can anyone please explain it to me by explaining "the …

Read More
How to get the current time in milliseconds from C in Linux?

How do I get the current time on Linux in milliseconds?

Read More