1CORE(5) Linux Programmer's Manual CORE(5)
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6 core - core dump file
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9 The default action of certain signals is to cause a process to termi‐
10 nate and produce a core dump file, a file containing an image of the
11 process's memory at the time of termination. This image can be used in
12 a debugger (e.g., gdb(1)) to inspect the state of the program at the
13 time that it terminated. A list of the signals which cause a process
14 to dump core can be found in signal(7).
15 A process can set its soft RLIMIT_CORE resource limit to place an upper
17 limit on the size of the core dump file that will be produced if it re‐
18 ceives a "core dump" signal; see getrlimit(2) for details.
19 There are various circumstances in which a core dump file is not pro‐
21 duced:
22 * The process does not have permission to write the core file. (By
24 default, the core file is called core or core.pid, where pid is the
25 ID of the process that dumped core, and is created in the current
26 working directory. See below for details on naming.) Writing the
27 core file fails if the directory in which it is to be created is not
28 writable, or if a file with the same name exists and is not writable
29 or is not a regular file (e.g., it is a directory or a symbolic
30 link).
31 * A (writable, regular) file with the same name as would be used for
33 the core dump already exists, but there is more than one hard link
34 to that file.
35 * The filesystem where the core dump file would be created is full; or
37 has run out of inodes; or is mounted read-only; or the user has
38 reached their quota for the filesystem.
39 * The directory in which the core dump file is to be created does not
41 exist.
42 * The RLIMIT_CORE (core file size) or RLIMIT_FSIZE (file size) re‐
44 source limits for the process are set to zero; see getrlimit(2) and
45 the documentation of the shell's ulimit command (limit in csh(1)).
46 * The binary being executed by the process does not have read permis‐
48 sion enabled. (This is a security measure to ensure that an exe‐
49 cutable whose contents are not readable does not produce a—possibly
50 readable—core dump containing an image of the executable.)
51 * The process is executing a set-user-ID (set-group-ID) program that
53 is owned by a user (group) other than the real user (group) ID of
54 the process, or the process is executing a program that has file ca‐
55 pabilities (see capabilities(7)). (However, see the description of
56 the prctl(2) PR_SET_DUMPABLE operation, and the description of the
57 /proc/sys/fs/suid_dumpable file in proc(5).)
58 * /proc/sys/kernel/core_pattern is empty and /proc/sys/ker‐
60 nel/core_uses_pid contains the value 0. (These files are described
61 below.) Not