Core

• Produce a corefile for a running process with gcore(1)
• The RLIMIT_CORE rlimit specifies the maximum size of a corefile
  • Use 0 to disable corefile generation, and "unlimited" for no explicit restriction on coredump size.
  • pam might be setting a hard limit at login time. Check /etc/security/limits.conf.

FreeBSD

• sysctl kern.corefile controls naming mechanisms. See the core(5) man page.
• sysctl kern.sugid_coredump controls whether processes with different effective and real U/GIDs produce corefiles
• See savecore(8) and crashinfo(8) for further FreeBSD-specific capabilities

Linux

• /proc/sys/kernel/core_pattern allows core naming to be configured (since Linux 2.6 and 2.4.21), and corefiles to be piped to programs. See the core(5) man page.
• /proc/sys/kernel/core_uses_pid controls whether the PID is appended to the corefile's name
• The prctl flag PR_SET_DUMPABLE allows process-specific coredump generation settings
• /proc/sys/fs/suid_dumpable
• /proc/PID/coredump_filter allows memory map-specific coredump generation settings

gcc

(largely taken from the Valgrind FAQ)

If they're not detailed enough, make sure you are compiling with -g to add debug information. And don't strip symbol tables (programs should be unstripped unless you run 'strip' on them; some libraries ship stripped). Also, -fomit-frame-pointer and -fstack-check can make stack traces worse. Some example sub-traces:

• With debug information and unstripped (best):

Invalid write of size 1
       at 0x80483BF: really (malloc1.c:20)
       by 0x8048370: main (malloc1.c:9)

• With no debug information, unstripped:

Invalid write of size 1
       at 0x80483BF: really (in /auto/homes/njn25/grind/head5/a.out)
       by 0x8048370: main (in /auto/homes/njn25/grind/head5/a.out)

• With no debug information, stripped:

Invalid write of size 1
       at 0x80483BF: (within /auto/homes/njn25/grind/head5/a.out)
       by 0x8048370: (within /auto/homes/njn25/grind/head5/a.out)
       by 0x42015703: __libc_start_main (in /lib/tls/libc-2.3.2.so)
       by 0x80482CC: (within /auto/homes/njn25/grind/head5/a.out)

• With debug information and -fomit-frame-pointer:

Invalid write of size 1
       at 0x80483C4: really (malloc1.c:20)
       by 0x42015703: __libc_start_main (in /lib/tls/libc-2.3.2.so)
       by 0x80482CC: ??? (start.S:81)

• A leak error message involving an unloaded shared object:

84 bytes in 1 blocks are possibly lost in loss record 488 of 713
       at 0x1B9036DA: operator new(unsigned) (vg_replace_malloc.c:132)
       by 0x1DB63EEB: ???
       by 0x1DB4B800: ???
       by 0x1D65E007: ???
       by 0x8049EE6: main (main.cpp:24)