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Core
From dankwiki
- 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)
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)