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* Produce a corefile for a running process with <tt>gcore</tt>(1) | * Produce a corefile for a running process with <tt>gcore</tt>(1) | ||
* The RLIMIT_CORE [[rlimit]] specifies the maximum size of a corefile | * 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 <tt>/etc/security/limits.conf</tt>. | |||
==FreeBSD== | ==FreeBSD== | ||
* sysctl <tt>kern.corefile</tt> controls naming mechanisms. See the <tt>core(5)</tt> man page. | * sysctl <tt>kern.corefile</tt> controls naming mechanisms. See the <tt>core(5)</tt> man page. | ||
| Line 16: | Line 17: | ||
==[[gcc]]== | ==[[gcc]]== | ||
(largely taken from the [http://valgrind.org/docs/manual/faq.html#faq.unhelpful Valgrind FAQ]) | (largely taken from the [http://valgrind.org/docs/manual/faq.html#faq.unhelpful 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. | 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: | Some example sub-traces: | ||
Latest revision as of 02:25, 17 June 2011
- 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)
