SymbX/systemd
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

coredump: add COREDUMP_CODE field for signal reason

Browse Source 
Introduce COREDUMP_CODE as a new captured field alongside the existing
COREDUMP_SIGNAL. While COREDUMP_SIGNAL identifies the signal number that
terminated the process, COREDUMP_CODE provides the reason the signal was sent.

For example, a process terminated by SIGSEGV due to invalid permissions would
produce COREDUMP_SIGNAL=11 and COREDUMP_CODE=2 (SEGV_ACCERR).

The kernel exposes coredump_code via pidfd starting with v7.1:
https://git.kernel.org/torvalds/c/701f7f4fbabbf4989ba6fbf033b160dd943221d5

System administrators can find both the signal and code in coredumpctl info:

$ coredumpctl info | grep Signal:
        Signal: 11 (SEGV) si_code: SEGV_MAPERR

Signed-off-by: Emanuele Rocca <emanuele.rocca@arm.com>
This commit is contained in:
Emanuele Rocca
2026-05-19 08:28:53 +00:00
parent c8c1bcf194
commit ed143d8623
5 changed files with 95 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files
man/systemd-coredump.xml
+14
View File
@@ -201,6 +201,7 @@ COREDUMP_UID=1000
COREDUMP_GID=1000
COREDUMP_SIGNAL_NAME=SIGSEGV
COREDUMP_SIGNAL=11
COREDUMP_CODE=2
COREDUMP_TIMESTAMP=1614342930000000
COREDUMP_COMM=Web Content
COREDUMP_EXE=/usr/lib64/firefox/firefox
@@ -327,6 +328,19 @@ COREDUMP_FILENAME=/var/lib/systemd/coredump/core.Web….552351.….zst
</listitem>
</varlistentry>
<varlistentry>
<term><varname>COREDUMP_CODE=</varname></term>
<listitem><para>The reason why the signal was sent as a numerical value. The code is defined as
field <varname>si_code</varname> in the <varname>siginfo_t</varname> structure and
documented in <citerefentry
project='man-pages'><refentrytitle>sigaction</refentrytitle><manvolnum>2</manvolnum></citerefentry>.
</para>
<xi:include href="version-info.xml" xpointer="v261"/>
</listitem>
</varlistentry>
<varlistentry>
<term><varname>COREDUMP_CWD=</varname></term>
<term><varname>COREDUMP_ROOT=</varname></term>
src/coredump/coredump-context.c
+47
View File
@@ -14,6 +14,7 @@
#include "memstream-util.h"
#include "namespace-util.h"
#include "parse-util.h"
#include "pidfd-util.h"
#include "process-util.h"
#include "signal-util.h"
#include "special.h"
@@ -38,6 +39,7 @@ static const char * const metadata_field_table[_META_MAX] = {
[META_UNIT] = "COREDUMP_UNIT=",
[META_PROC_AUXV] = "COREDUMP_PROC_AUXV=",
[META_THREAD_NAME] = "COREDUMP_THREAD_NAME=",
[META_CODE] = "COREDUMP_CODE=",
};
DEFINE_PRIVATE_STRING_TABLE_LOOKUP_TO_STRING(metadata_field, MetadataField);
@@ -176,6 +178,34 @@ static int get_process_container_parent_cmdline(PidRef *pid, char** ret_cmdline)
return 1;
}
/* The kernel passes si_signo through core_pattern (%s). Starting with v7.1,
* si_code is reported as well via pidfd. */
static int coredump_context_read_pidfd_info(CoredumpContext *context) {
struct pidfd_info info = {
.mask = PIDFD_INFO_COREDUMP,
};
int r;
assert(context);
assert(pidref_is_set(&context->pidref));
if (!context->got_pidfd || context->pidref.fd < 0)
return 0;
r = pidfd_get_info(context->pidref.fd, &info);
if (ERRNO_IS_NEG_NOT_SUPPORTED(r))
return log_debug_errno(r, "PIDFD_INFO_COREDUMP not supported, ignoring: %m");
if (r < 0)
return log_debug_errno(r, "Failed to get pidfd coredump info, ignoring: %m");
if (FLAGS_SET(info.mask, PIDFD_INFO_COREDUMP_CODE)) {
context->code = (int) info.coredump_code;
context->got_code = true;
}
return 0;
}
int coredump_context_build_iovw(CoredumpContext *context) {
char *t;
int r;
@@ -213,6 +243,10 @@ int coredump_context_build_iovw(CoredumpContext *context) {
return log_error_errno(r, "Failed to add COREDUMP_SIGNAL= field: %m");
(void) iovw_put_string_field(&context->iovw, "COREDUMP_SIGNAL_NAME=SIG", signal_to_string(context->signo));
/* Emit si_code if we learned it from pidfd_info */
if (context->got_code)
(void) iovw_put_string_fieldf(&context->iovw, "COREDUMP_CODE=", "%i", context->code);
}
r = iovw_put_string_fieldf(&context->iovw, "COREDUMP_TIMESTAMP=", USEC_FMT, context->timestamp);
@@ -367,6 +401,8 @@ static int coredump_context_parse_from_procfs(CoredumpContext *context) {
if (r < 0)
log_warning_errno(r, "Failed to get auxv, ignoring: %m");
(void) coredump_context_read_pidfd_info(context);
r = pidref_verify(&context->pidref);
if (r < 0)
return log_error_errno(r, "PIDFD validation failed: %m");
@@ -499,6 +535,17 @@ static int context_parse_one(CoredumpContext *context, MetadataField meta, bool
case META_THREAD_NAME:
return free_and_strdup_warn(&context->thread_name, s);
case META_CODE:
/* We must accept both positive and negative values. The former
* are reserved for kernel-generated signals, the latter for signals requested
* from userspace. See /usr/include/bits/siginfo-consts.h. */
r = safe_atoi(s, &context->code);
if (r < 0)
log_warning_errno(r, "Failed to parse code \"%s\", ignoring: %m", s);
else
context->got_code = true;
return 0;
case META_PROC_AUXV: {
char *t = memdup_suffix0(s, size);
if (!t)
src/coredump/coredump-context.h
+3
View File
@@ -42,6 +42,7 @@ typedef enum MetadataField {
META_UNIT,
META_PROC_AUXV,
META_THREAD_NAME,
META_CODE, /* code of signal causing dump (eg: 2 for SEGV_ACCERR). Since v7.1. */
_META_MAX,
_META_INVALID = -EINVAL,
} MetadataField;
@@ -51,6 +52,7 @@ struct CoredumpContext {
uid_t uid; /* META_ARGV_UID */
gid_t gid; /* META_ARGV_GID */
int signo; /* META_ARGV_SIGNAL */
int code; /* META_CODE */
usec_t timestamp; /* META_ARGV_TIMESTAMP */
uint64_t rlimit; /* META_ARGV_RLIMIT */
char *hostname; /* META_ARGV_HOSTNAME */
@@ -63,6 +65,7 @@ struct CoredumpContext {
size_t auxv_size; /* META_PROC_AUXV */
char *thread_name; /* META_THREAD_NAME */
bool got_pidfd; /* META_ARGV_PIDFD */
bool got_code; /* META_CODE */
bool same_pidns;
bool forwarded;
int input_fd;
src/coredump/coredumpctl.c
+25 -4
View File
@@ -585,6 +585,7 @@ typedef enum CoredumpField {
COREDUMP_FIELD_UID,
COREDUMP_FIELD_GID,
COREDUMP_FIELD_SGNL,
COREDUMP_FIELD_CODE,
COREDUMP_FIELD_EXE,
COREDUMP_FIELD_COMM,
COREDUMP_FIELD_CMDLINE,
@@ -615,6 +616,7 @@ static const char* const coredump_field_table[_COREDUMP_FIELD_MAX] = {
[COREDUMP_FIELD_UID] = "COREDUMP_UID",
[COREDUMP_FIELD_GID] = "COREDUMP_GID",
[COREDUMP_FIELD_SGNL] = "COREDUMP_SIGNAL",
[COREDUMP_FIELD_CODE] = "COREDUMP_CODE",
[COREDUMP_FIELD_EXE] = "COREDUMP_EXE",
[COREDUMP_FIELD_COMM] = "COREDUMP_COMM",
[COREDUMP_FIELD_CMDLINE] = "COREDUMP_CMDLINE",
@@ -770,9 +772,23 @@ static int print_info(FILE *file, sd_journal *j, bool need_space) {
int sig;
const char *name = f.normal_coredump ? "Signal" : "Reason";
if (f.normal_coredump && safe_atoi(f.fields[COREDUMP_FIELD_SGNL], &sig) >= 0)
fprintf(file, " %s: %s (%s)\n", name, f.fields[COREDUMP_FIELD_SGNL], signal_to_string(sig));
else
if (f.normal_coredump && safe_atoi(f.fields[COREDUMP_FIELD_SGNL], &sig) >= 0) {
fprintf(file, " %s: %s (%s)", name, f.fields[COREDUMP_FIELD_SGNL], signal_to_string(sig));
if (f.fields[COREDUMP_FIELD_CODE]) {
int n;
const char *s;
if (safe_atoi(f.fields[COREDUMP_FIELD_CODE], &n) >= 0)
s = signal_code_to_string(sig, n);
else
s = NULL;
fprintf(file, " si_code: %s", s ?: f.fields[COREDUMP_FIELD_CODE]);
}
fputc('\n', file);
} else
fprintf(file, " %s: %s\n", name, f.fields[COREDUMP_FIELD_SGNL]);
}
@@ -893,7 +909,8 @@ static int print_info_json(FILE *file, sd_journal *j) {
pid_t pid_as_int = 0, tid_as_int = 0;
uid_t uid_as_int = UID_INVALID, owner_uid_as_int = UID_INVALID;
gid_t gid_as_int = GID_INVALID;
int sig_as_int = 0;
int sig_as_int = 0, code_as_int = 0;
bool code_is_valid = false;
usec_t ts = USEC_INFINITY;
int r;
@@ -916,6 +933,8 @@ static int print_info_json(FILE *file, sd_journal *j) {
(void) parse_uid(f.fields[COREDUMP_FIELD_OWNER_UID], &owner_uid_as_int);
if (f.normal_coredump && f.fields[COREDUMP_FIELD_SGNL])
(void) safe_atoi(f.fields[COREDUMP_FIELD_SGNL], &sig_as_int);
if (f.normal_coredump && f.fields[COREDUMP_FIELD_CODE])
code_is_valid = safe_atoi(f.fields[COREDUMP_FIELD_CODE], &code_as_int) >= 0;
if (f.fields[COREDUMP_FIELD_TIMESTAMP])
(void) safe_atou64(f.fields[COREDUMP_FIELD_TIMESTAMP], &ts);
@@ -932,6 +951,8 @@ static int print_info_json(FILE *file, sd_journal *j) {
SD_JSON_BUILD_PAIR_CONDITION(f.normal_coredump && sig_as_int > 0, "Signal", SD_JSON_BUILD_INTEGER(sig_as_int)),
SD_JSON_BUILD_PAIR_CONDITION(f.normal_coredump && sig_as_int > 0 && !!signal_to_string(sig_as_int), "SignalName", SD_JSON_BUILD_STRING(signal_to_string(sig_as_int))),
SD_JSON_BUILD_PAIR_CONDITION(f.normal_coredump && sig_as_int <= 0 && !!f.fields[COREDUMP_FIELD_SGNL], "Signal", SD_JSON_BUILD_STRING(f.fields[COREDUMP_FIELD_SGNL])),
SD_JSON_BUILD_PAIR_CONDITION(f.normal_coredump && code_is_valid, "SignalCode", SD_JSON_BUILD_INTEGER(code_as_int)),
SD_JSON_BUILD_PAIR_CONDITION(f.normal_coredump && !code_is_valid && !!f.fields[COREDUMP_FIELD_CODE], "SignalCode", SD_JSON_BUILD_STRING(f.fields[COREDUMP_FIELD_CODE])),
SD_JSON_BUILD_PAIR_CONDITION(!f.normal_coredump && !!f.fields[COREDUMP_FIELD_SGNL], "Reason", SD_JSON_BUILD_STRING(f.fields[COREDUMP_FIELD_SGNL])),
SD_JSON_BUILD_PAIR_CONDITION(ts != USEC_INFINITY, "Timestamp", SD_JSON_BUILD_UNSIGNED(ts)),
SD_JSON_BUILD_PAIR_CONDITION(ts == USEC_INFINITY && !!f.fields[COREDUMP_FIELD_TIMESTAMP], "Timestamp", SD_JSON_BUILD_STRING(f.fields[COREDUMP_FIELD_TIMESTAMP])),
test/units/TEST-87-AUX-UTILS-VM.coredump.sh
+6
View File
@@ -166,6 +166,12 @@ coredumpctl info "$CORE_TEST_BIN" | grep "TID:" >/dev/null
# Check the field is queryable in the journal
coredumpctl -F COREDUMP_TID
# If COREDUMP_CODE= is present, check that the expected code is SI_USER (0).
if coredumpctl -F COREDUMP_CODE | grep "^0$" >/dev/null; then
coredumpctl info "$CORE_TEST_BIN" | grep --fixed-strings "Signal: 5 (TRAP) si_code: SI_USER" >/dev/null
coredumpctl info --json=short "$CORE_TEST_BIN" | jq -se 'any(.[]; .SignalCode == 0)'
fi
coredumpctl debug --debugger=/bin/true "$CORE_TEST_BIN"
SYSTEMD_DEBUGGER=/bin/true coredumpctl debug "$CORE_TEST_BIN"
coredumpctl debug --debugger=/bin/true --debugger-arguments="-this --does --not 'do anything' -a -t --all" "${CORE_TEST_BIN##*/}"