Add %I (TID in initial PID namespace) to the core_pattern, so the
kernel passes the crashing thread's TID to systemd-coredump. Use it
to read the thread's comm name from /proc/<tid>/comm and log both as
new journal fields:
COREDUMP_TID= — TID of the crashing thread
COREDUMP_THREAD_NAME= — comm name of the crashing thread
These fields are also stored as xattrs on external coredump files
(user.coredump.tid, user.coredump.thread_name) and displayed by
coredumpctl info alongside the PID line.
For single-threaded processes the TID equals the PID and thread_name
equals comm; for multi-threaded programs with named worker threads
(pthread_setname_np / PR_SET_NAME) this identifies which thread
crashed without needing to open the coredump file itself.
The new fields are optional in the socket forwarding path, so older
systemd-coredump senders are handled gracefully.
Co-developed-by: Claude <claude@anthropic.com>
Alpine/postmarketOS build coreutils with --enable-single-binary=symlinks.
In that case, all commands provided by coreutils are symlink to
/usr/bin/coreutils, and it calls prctl(PR_SET_NAME, argv[0]), hence the comm
will be the path to the symlink.
This also makes not kill sleep command with SIGKILL in TEST-17-UDEV, that is
totally unnecessary.
The EnterNamespace= feature currently doesn't work if the debuginfo is
separated from the crashing binary. Until that's resolved, let's run the
test only if the test binary has embedded debuginfo (.debug_info
section; e.g. when systemd is built without WITH_DEBUG=1) or it contains
MiniDebugInfo (.gnu_debugdata section; default on Fedora and CentOS).
See: https://github.com/systemd/systemd/pull/39268#issuecomment-3390745718
This also makes shebang always use env command, and drops unnecessary
'bash -c' or 'sh -c' when a signle command is invoked in the shell,
like sleep or echo.
Follow-ups for ab56a96194.
Fixes the following failure:
```
TEST-87-AUX-UTILS-VM.sh[1196]: + systemd-run --user --wait --pipe -M testuser@.host -- coredumpctl
TEST-87-AUX-UTILS-VM.sh[1840]: Running as unit: run-p1840-i1841.service; invocation ID: 325a026377aa4cffb046c5a63a8906ab
TEST-87-AUX-UTILS-VM.sh[1853]: Hint: You are currently not seeing messages from other users and the system.
TEST-87-AUX-UTILS-VM.sh[1853]: Users in groups 'adm', 'systemd-journal', 'wheel' can see all messages.
TEST-87-AUX-UTILS-VM.sh[1853]: Pass -q to turn off this notice.
TEST-87-AUX-UTILS-VM.sh[1853]: Journal file /var/log/journal/6835d335b6684b6197bf071ad66f2678/user-4711.journal is truncated, ignoring file.
TEST-87-AUX-UTILS-VM.sh[1853]: No coredumps found.
TEST-87-AUX-UTILS-VM.sh[1840]: Finished with result: exit-code
TEST-87-AUX-UTILS-VM.sh[1840]: Main processes terminated with: code=exited, status=1/FAILURE
TEST-87-AUX-UTILS-VM.sh[1840]: Service runtime: 154ms
TEST-87-AUX-UTILS-VM.sh[1840]: CPU time consumed: 78ms
TEST-87-AUX-UTILS-VM.sh[1840]: Memory peak: 21.9M (swap: 0B)
```
A new core was added to the test, but the loop counter was not increased
to wait for it, so the test races against systemd-coredump's processing.
This failed at least once in debci:
8015s [ 32.227813] TEST-87-AUX-UTILS-VM.sh[1038]: + coredumpctl info COREDUMP_TIMESTAMP=1679509902000000
8015s [ 32.228684] TEST-87-AUX-UTILS-VM.sh[1723]: No coredumps found.
Follow-up for 0c49e0049b
Fixes https://github.com/systemd/systemd/issues/37666
The kernel provides %d which is documented as
"dump mode—same as value returned by prctl(2) PR_GET_DUMPABLE".
We already query /proc/pid/auxv for this information, but unfortunately this
check is subject to a race, because the crashed process may be replaced by an
attacker before we read this data, for example replacing a SUID process that
was killed by a signal with another process that is not SUID, tricking us into
making the coredump of the original process readable by the attacker.
With this patch, we effectively add one more check to the list of conditions
that need be satisfied if we are to make the coredump accessible to the user.
Reportedy-by: Qualys Security Advisory <qsa@qualys.com>
In principle, %d might return a value other than 0, 1, or 2 in the future.
Thus, we accept those, but emit a notice.
This was broken in f45b801551. 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.
TEST-74-AUX-UTILS covers many subtests, as it's a catch-all job, and a few
need a VM to run. The job is thus marked VM-only. But that means in settings
where we can't run VM tests (no KVM available), the entire thing is skipped,
losing tons of coverage that doesn't need skipping.
Move the VM-only subtests to TEST-87-AUX-UTILS-VM that is configured to only
run in VMs under both runners. This way we keep the existing tests as-is, and
we can add new VM-only tests without worrying. This is how the rest of the
tests are organized.
Follow-up for f4faac2073
noxiouz
Yu Watanabe
Daan De Meyer
Frantisek Sumsal
Luca Boccassi
Zbigniew Jędrzejewski-Szmek