systemd/1279-coredump-restore-compatibility-with-older-patterns.patch
Jan Macku a673ceed38 systemd-252-60
Resolves: RHEL-115182,RHEL-97175,RHEL-107268
2025-11-05 09:44:11 +01:00

123 lines
6.3 KiB
Diff

From 38d7a52bcdad1cef1dba218f86e3905c24d51d9a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
Date: Tue, 29 Apr 2025 14:47:59 +0200
Subject: [PATCH] coredump: restore compatibility with older patterns
This was broken in f45b8015513d38ee5f7cc361db9c5b88c9aae704. Unfortunately
the review does not talk about backward compatibility at all. There are
two places where it matters:
- During upgrades, the replacement of kernel.core_pattern is asynchronous.
For example, during rpm upgrades, it would be updated a post-transaction
file trigger. In other scenarios, the update might only happen after
reboot. We have a potentially long window where the old pattern is in
place. We need to capture coredumps during upgrades too.
- With --backtrace. The interface of --backtrace, in hindsight, is not
great. But there are users of --backtrace which were written to use
a specific set of arguments, and we can't just break compatiblity.
One example is systemd-coredump-python, but there are also reports of
users using --backtrace to generate coredump logs.
Thus, we require the original set of args, and will use the additional args if
found.
A test is added to verify that --backtrace works with and without the optional
args.
(cherry picked from commit ded0aac389e647d35bce7ec4a48e718d77c0435b)
Related: RHEL-104138
---
src/coredump/coredump.c | 23 +++++++++++++++--------
test/units/testsuite-74.coredump.sh | 18 +++++++++++-------
2 files changed, 26 insertions(+), 15 deletions(-)
diff --git a/src/coredump/coredump.c b/src/coredump/coredump.c
index b24f4c8cc3..458857ffb2 100644
--- a/src/coredump/coredump.c
+++ b/src/coredump/coredump.c
@@ -94,8 +94,12 @@ enum {
META_ARGV_SIGNAL, /* %s: number of signal causing dump */
META_ARGV_TIMESTAMP, /* %t: time of dump, expressed as seconds since the Epoch (we expand this to µs granularity) */
META_ARGV_RLIMIT, /* %c: core file size soft resource limit */
- META_ARGV_HOSTNAME, /* %h: hostname */
+ _META_ARGV_REQUIRED,
+ /* The fields below were added to kernel/core_pattern at later points, so they might be missing. */
+ META_ARGV_HOSTNAME = _META_ARGV_REQUIRED, /* %h: hostname */
_META_ARGV_MAX,
+ /* If new fields are added, they should be added here, to maintain compatibility
+ * with callers which don't know about the new fields. */
/* The following indexes are cached for a couple of special fields we use (and
* thereby need to be retrieved quickly) for naming coredump files, and attaching
@@ -106,7 +110,7 @@ enum {
_META_MANDATORY_MAX,
/* The rest are similar to the previous ones except that we won't fail if one of
- * them is missing. */
+ * them is missing in a message sent over the socket. */
META_EXE = _META_MANDATORY_MAX,
META_UNIT,
@@ -1068,7 +1072,7 @@ static int save_context(Context *context, const struct iovec_wrapper *iovw) {
}
/* The basic fields from argv[] should always be there, refuse early if not */
- for (int i = 0; i < _META_ARGV_MAX; i++)
+ for (int i = 0; i < _META_ARGV_REQUIRED; i++)
if (!context->meta[i])
return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "A required (%s) has not been sent, aborting.", meta_field_names[i]);
@@ -1286,14 +1290,17 @@ static int gather_pid_metadata_from_argv(
char *t;
/* We gather all metadata that were passed via argv[] into an array of iovecs that
- * we'll forward to the socket unit */
+ * we'll forward to the socket unit.
+ *
+ * We require at least _META_ARGV_REQUIRED args, but will accept more.
+ * We know how to parse _META_ARGV_MAX args. The rest will be ignored. */
- if (argc < _META_ARGV_MAX)
+ if (argc < _META_ARGV_REQUIRED)
return log_error_errno(SYNTHETIC_ERRNO(EINVAL),
- "Not enough arguments passed by the kernel (%i, expected %i).",
- argc, _META_ARGV_MAX);
+ "Not enough arguments passed by the kernel (%i, expected between %i and %i).",
+ argc, _META_ARGV_REQUIRED, _META_ARGV_MAX);
- for (int i = 0; i < _META_ARGV_MAX; i++) {
+ for (int i = 0; i < MIN(argc, _META_ARGV_MAX); i++) {
t = argv[i];
diff --git a/test/units/testsuite-74.coredump.sh b/test/units/testsuite-74.coredump.sh
index 1093cad8a9..0163131096 100755
--- a/test/units/testsuite-74.coredump.sh
+++ b/test/units/testsuite-74.coredump.sh
@@ -218,14 +218,18 @@ rm -f /tmp/core.{output,redirected}
(! "${UNPRIV_CMD[@]}" coredumpctl dump "$CORE_TEST_BIN" >/dev/null)
# --backtrace mode
-# Pass one of the existing journal coredump records to systemd-coredump and
-# use our PID as the source to make matching the coredump later easier
-# systemd-coredump args: PID UID GID SIGNUM TIMESTAMP CORE_SOFT_RLIMIT HOSTNAME
+# Pass one of the existing journal coredump records to systemd-coredump.
+# Use our PID as the source to be able to create a PIDFD and to make matching easier.
+# systemd-coredump args: PID UID GID SIGNUM TIMESTAMP CORE_SOFT_RLIMIT [HOSTNAME]
journalctl -b -n 1 --output=export --output-fields=MESSAGE,COREDUMP COREDUMP_EXE="/usr/bin/test-dump" |
- /usr/lib/systemd/systemd-coredump --backtrace $$ 0 0 6 1679509994 12345 mymachine
-# Wait a bit for the coredump to get processed
-timeout 30 bash -c "while [[ \$(coredumpctl list -q --no-legend $$ | wc -l) -eq 0 ]]; do sleep 1; done"
-coredumpctl info "$$"
+ /usr/lib/systemd/systemd-coredump --backtrace $$ 0 0 6 1679509900 12345
+journalctl -b -n 1 --output=export --output-fields=MESSAGE,COREDUMP COREDUMP_EXE="/usr/bin/test-dump" |
+ /usr/lib/systemd/systemd-coredump --backtrace $$ 0 0 6 1679509901 12345 mymachine
+# Wait a bit for the coredumps to get processed
+timeout 30 bash -c "while [[ \$(coredumpctl list -q --no-legend $$ | wc -l) -lt 2 ]]; do sleep 1; done"
+coredumpctl info $$
+coredumpctl info COREDUMP_TIMESTAMP=1679509900000000
+coredumpctl info COREDUMP_TIMESTAMP=1679509901000000
coredumpctl info COREDUMP_HOSTNAME="mymachine"
# This used to cause a stack overflow