説明
特定のシグナルのデフォルトのアクションは、プロセスを終了させ、コアダンプファイル（終了時のプロセスのメモリのイメージを含むディスクファイル）を生成することです。このイメージをデバッガー（gdb（1）など）で使用して、プログラムが終了した時点のプログラムの状態を検査できます。 プロセスにコアをダンプさせるシグナルのリストは、signal（7）にあります。
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コアダンプファイルが生成されないさまざまな状況があります。
* The process does not have permission to write the core file. (By
default, the core file is called core or core.pid, where pid is
the ID of the process that dumped core, and is created in the
current working directory. See below for details on naming.)
Writing the core file will fail if the directory in which it is to
be created is nonwritable, or if a file with the same name exists
and is not writable or is not a regular file (e.g., it is a
directory or a symbolic link).
* A (writable, regular) file with the same name as would be used for
the core dump already exists, but there is more than one hard link
to that file.
* The filesystem where the core dump file would be created is full;
or has run out of inodes; or is mounted read-only; or the user has
reached their quota for the filesystem.
* The directory in which the core dump file is to be created does
not exist.
* The RLIMIT_CORE (core file size) or RLIMIT_FSIZE (file size)
resource limits for the process are set to zero; see getrlimit(2)
and the documentation of the shell's ulimit command (limit in
csh(1)).
* The binary being executed by the process does not have read
permission enabled.
* The process is executing a set-user-ID (set-group-ID) program that
is owned by a user (group) other than the real user (group) ID of
the process, or the process is executing a program that has file
capabilities (see capabilities(7)). (However, see the description
of the prctl(2) PR_SET_DUMPABLE operation, and the description of
the /proc/sys/fs/suid_dumpable file in proc(5).)
* (Since Linux 3.7) The kernel was configured without the
CONFIG_COREDUMP option.
さらに、madvise（2）MADV_DONTDUMPフラグが使用された場合、コアダンプはプロセスのアドレス空間の一部を除外する場合があります。
コアダンプファイルの命名
デフォルトでは、コアダンプファイルはcoreという名前ですが、/ proc / sys / kernel / core_patternファイル（Linux 2.6および2.4.21以降）を設定して、コアダンプファイルに名前を付けるために使用されるテンプレートを定義できます。テンプレートには、コアファイルの作成時に次の値で置き換えられる％指定子を含めることができます。
%% a single % character
%c core file size soft resource limit of crashing process (since
Linux 2.6.24)
%d dump mode—same as value returned by prctl(2) PR_GET_DUMPABLE
(since Linux 3.7)
%e executable filename (without path prefix)
%E pathname of executable, with slashes ('/') replaced by
exclamation marks ('!') (since Linux 3.0).
%g (numeric) real GID of dumped process
%h hostname (same as nodename returned by uname(2))
%i TID of thread that triggered core dump, as seen in the PID
namespace in which the thread resides (since Linux 3.18)
%I TID of thread that triggered core dump, as seen in the
initial PID namespace (since Linux 3.18)
%p PID of dumped process, as seen in the PID namespace in which
the process resides
%P PID of dumped process, as seen in the initial PID namespace
(since Linux 3.12)
%s number of signal causing dump
%t time of dump, expressed as seconds since the Epoch,
1970-01-01 00:00:00 +0000 (UTC)
%u (numeric) real UID of dumped process
gdb path-to-your-binary path-to-corefile、必要なのはコマンドのみで、info stackその後にCtrl-d。唯一心配なのは、コアダンプが通常のことだということです。