Selective core dump in Linux - How can I select the dumped sections?

Question

I am looking for a way to select the sections and memory regions included in a core dump.
My application\'s core dump size is about 30GB, most of it is in preallocated buffe

Answer 1

According to the core(5) manpage, you can set which mappings are written to the core file:

Since kernel 2.6.23, the Linux-specific /proc/PID/coredump_filter file can be used to control which memory segments are written to the core dump file in the event that a core dump is performed for the process with the corresponding process ID.

The value in the file is a bit mask of memory mapping types (see mmap(2)). If a bit is set in the mask, then memory mappings of the corresponding type are dumped; otherwise they are not dumped. The bits in this file have the following meanings:

       bit 0  Dump anonymous private mappings.
       bit 1  Dump anonymous shared mappings.
       bit 2  Dump file-backed private mappings.
       bit 3  Dump file-backed shared mappings.
       bit 4 (since Linux 2.6.24)
              Dump ELF headers.
       bit 5 (since Linux 2.6.28)
              Dump private huge pages.
       bit 6 (since Linux 2.6.28)
              Dump shared huge pages.

By default, the following bits are set: 0, 1, 4 (if the CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS kernel configuration option is enabled), and 5. The value of this file is displayed in hexadecimal. (The default value is thus displayed as 33.) Memory-mapped I/O pages such as frame buffer are never dumped, and virtual DSO pages are always dumped, regardless of the coredump_filter value.

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This file is only provided if the kernel was built with the CONFIG_ELF_CORE configuration option.

Answer 2

I'm not sure if it is possible to set which part of the memory to dump.

From man 5 core

disk file containing an image of the process's memory at the time of termination

As an option you can truncate core file using setrlimit with a RLIMIT_CORE parameter.