systemd
zero-byte svg file generated when systemd-bootchart invoked using "init" kernel parameter
According to man systemd-bootchart, the recommended way of running systemd-bootchart is using the init kernel parameter (which you can set from the grub menu):
init=/usr/lib/systemd/systemd-bootchart
Unfortunately, this seems to have stopped working.
On Fedora 41, with systemd v256, the generated svg file is zero bytes:
Fedora Linux 41 (Server Edition)
Kernel 6.11.4-301.fc41.aarch64 on an aarch64 (tty1)
vbox login: jmuir
Password:
Last login: Tue Jan 14 14:16:28 on tty1
jmuir@vbox:~$ ls -1 /run/log
total 0
rw-rw-rw-. 1 root root 0 Jan 14 14:22 bootchart-20250114-1422.svg
drwxr-sr-x+ 2 root systemd-journal 40 Jan 14 14:22 journal
Here is my kernel command-line:
jmuir@vbox:~$ xargs -n1 < /proc/cmdline
BOOT_IMAGE=(hdB,gpt2)/vmlinuz-6.11.4-301.fc41.aarch64
root=/dev/mapper/fedora_vbox-root
ro
rd.lum.lu=fedora_vbox/root
rhgb
init=/usr/1ib/systemd/systemd-bootchart
systemd-bootchart should run for about 3 mins (1800 samples at 10 samples/sec):
jmuir@vbox:~$ cat /etc/systemd/bootchart.conf
# This file is part of systemd.
#
# systemd is free software; you can redistribute it and/or modify it
# under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2.1 of the License, or
# (at your option) any later version.
#
# Entries in this file show the compile time defaults.
# You can change settings by editing this file.
# Defaults can be restored by simply deleting this file.
# See bootchart.conf (5) for details.
[Bootchart]
Samples=1800
Frequency=10
#Relative=no
#Filter=yes
#Output=<folder name, defaults to /run/log>
#Init=/path/to/init-binary
#PlotMemoryUsage=no
#PlotEntropyGraph=no
#ScaleX=100
#ScaleY=20
#ControlGroup=no
#PerCPU=no
Version information:
jmuir@vbox:~$ systemctl --version
systemd 256 (256.7-1.fc41)
+PAM *AUDIT +SELINUX -APPARMOR *IMA SMACK *SECCOMP -GCRYPT *GNUTS OPENSSL *ACL *BLKID +CURL *ELFUTILS +FIDO2 +IDN -IDN -IPTC +KMOD *LIBCRYPTSETUP *LIBCRYPTS
ETUP_PLUGINS +LIBFDISK +PCREZ +PWQUALITY +P11KIT +QRENCODE +TPM +BZIP2 +LZA +XZ *ZLIB *ZSTD +BPF_FRAMEWORK *XKBCOMMON UTMP *SYSUINIT *LIBARCHIVE
jmuir@vbox:~$ strings /usr/lib/systemd/systemd-bootchart | grep systemd-bootchart
{"type" : "rpm", "name": "systend-bootchart"
systemd-bootchart wrote %s
systemd-bootchart: sample time overrun %i times
systemd-bootchart-235-1.fc41.aarch64 .debug
I was able to capture an strace log using the following debug init program:
// init-jm.c
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#define BOOTCHART "/usr/lib/systemd/systemd-bootchart"
#define SYSTEMD "/usr/lib/systemd/systemd"
#define STRACE "/usr/bin/strace"
int main() {
pid_t fpid;
pid_t mypid;
int fd = -1;
fd = open("/dev/kmsg", O_WRONLY);
mypid = getpid();
dprintf(fd, "begin init-jm, mypid=%d\n", mypid);
fpid = fork();
if (fpid < 0) {
perror("call to fork() failed");
} else if (fpid == 0) {
mypid = getpid();
dprintf(fd, "this is the child, mypid=%d\n", mypid);
execl(STRACE, "@strace", "-o", "/run/log/strace.log", BOOTCHART, NULL);
} else {
mypid = getpid();
dprintf(fd, "this is the parent, mypid=%d\n", mypid);
execl(SYSTEMD, SYSTEMD, NULL);
}
dprintf(fd, "end init-jm, mypid=%d\n", mypid);
return 0;
}
Here is the kernel command-line I used (note that I am running in permissive mode) and the resulting contents of /run/log:
jmuir@vbox:~$ xargs -n1 < /proc/cmdline
BOOT_IMAGE=(hd0,gpt2)/vmlinuz-6.11.4-301.fc41.aarch64
root=/dev/mapper/fedora_vbox-root
ro
rd.lvm.lv=fedora_vbox/root
rhgb
enforcing=0
init=/usr/lib/systemd/init-jm
jmuir@vbox:~$ ls -l /run/log
total 96
-rw-rw-rw-. 1 root root 0 Jan 14 16:00 bootchart-20250114-1600.svg
drwxr-sr-x+ 2 root systemd-journal 40 Jan 14 16:00 journal
-rw-rw-rw-. 1 root root 97423 Jan 14 16:00 strace.log
The strace log shows that systemd-bootchart is sent SIGHUP just after it starts executing.
...
pread64(166, "systemd-bootcha (512, #threads: "..., 4095, 0) = 4095
getdents64(5, 0xaaaad4d34640 /* 0 entries */, 32768) = 0
close(7) = 0
clock_nanosleep(CLOCK_REALTIME, 0, {tv_sec=0, tv_nsec=83836333}, NULL) = ? ERESTART_RESTARTBLOCK (Interrupted by signal)
--- SIGHUP {si_signo=SIGHUP, si_code=SI_USER, si_pid=1, si_uid=0} ---
--- SIGCONT {si_signo=SIGCONT, si_code=SI_USER, si_pid=1, si_uid=0} ---
rt_sigreturn({mask=[]}) = -1 EINTR (Interrupted system call)
close(9) = 0
close(8) = 0
close(11) = 0
close(10) = 0
close(13) = 0
...
in src/bootchart.c you can see that systemd-bootchart catches SIGHUP and then sets a global variable to exit its main loop nicely.
Full strace log is attached. strace-init-jm.log
@bluca , the root cause here is that PID 1 is sending SIGHUP to systemd-bootchart shortly after it starts up.
could this be a systemd defect?
maybe the issue should be moved/linked there.
Maybe not a bug, although if pid == 1 we can certainly ignore SIGHUP and a few other signals...
Yep I've noticed something similar myself. bootchart v235. systemd v257.4 Report isn't completely zero but seems cut early in boot at 3.3 sec or sth.
ootchart for srv0 - Fri, 27 Jun 2025 23:38:51 +0200 System: Linux 6.16.0-rc3 #26 SMP PREEMPT_DYNAMIC Mon Jun 23 01:34:14 CEST 2025 x86_64 CPU: Intel(R) Core(TM) i7-14700K Boot options: root=UUID=a569985f-a17f-4791-8aa8-b6d7e0d05604 rw rootflags=subvol=@rootfs transparent_hugepage=madvise init_on_alloc=0 init=/lib/systemd/systemd-bootchart initcall_debug consoleblank=180 quiet intel_iommu=on systemd.machine_id=4d478806645249708407d893e8506db2 Build: Debian GNU/Linux 12 (bookworm) Log start time: 3.363s Idle time: Not detected Graph data: 25.000 samples/sec, recorded 8000 total, dropped 0 samples, 356 processes, 283 filtere
I've enabled systemd service (post boot) it starts at 3.8 sec and look "normalish"
System: Linux 6.16.0-rc3 #26 SMP PREEMPT_DYNAMIC Mon Jun 23 01:34:14 CEST 2025 x86_64 CPU: Intel(R) Core(TM) i7-14700K Boot options: root=UUID=a569985f-a17f-4791-8aa8-b6d7e0d05604 rw rootflags=subvol=@rootfs transparent_hugepage=madvise init_on_alloc=0 init=/lib/systemd/systemd-bootchart initcall_debug consoleblank=180 quiet intel_iommu=on systemd.machine_id=4d478806645249708407d893e8506db2 Build: Debian GNU/Linux 12 (bookworm) Log start time: 3.815s Idle time: 19.143s Graph data: 25.000 samples/sec, recorded 8000 total, dropped 1 samples, 844991 processes, 267 filtered
idk
?
