Bug#984495: systemd segfault soon after daemon-reload

[Benjamin Poirier]

Package: systemd
Version: 241-7~deb10u4
Severity: important
Tags: upstream patch

Dear Maintainer,

A user of Cumulus Linux 4, which uses some Debian Buster packages
including systemd, reported a systemd crash:

2021-03-03T20:59:58.426342+00:00 <hostname> systemd[1]: Reloading.
2021-03-03T20:59:58.459909+00:00 <hostname> kernel: [ 4344.314153] systemd[1]: segfault at 50 ip 000055d419ce7080 sp 00007ffcecb91850 error 4 in systemd[55d419c8c000+b1000]
2021-03-03T20:59:58.459955+00:00 <hostname> kernel: [ 4344.326055] Code: 45 8c 48 8b 4d 90 c7 45 88 00 00 00 00 48 8b 94 c7 a0 04 00 00 48 89 85 70 ff ff ff 48 89 c8 48 39 d1 74 15 31 c9 0f 1f 40 00 <48> 8b 40 50 83 c1 01 48 39 c2 75 f4 89 4d 88 48 8b 45 90 48 8
b 58
2021-03-03T20:59:58.472662+00:00 <hostname> kernel: [ 4344.359412] systemd: 37 output lines suppressed due to ratelimiting
2021-03-03T20:59:58.472295+00:00 <hostname> systemd[1]: Caught <SEGV>, dumped core as pid 20486.
2021-03-03T20:59:58.495229+00:00 <hostname> systemd[1]: Freezing execution.

The core file shows the following information:
(gdb) info stack
#0  0x00007f9ac0f4ea97 in kill () from /lib/x86_64-linux-gnu/libc.so.6
#1  0x000055d419d3c4f6 in crash (sig=11) at ../src/core/main.c:197
#2  <signal handler called>
#3  service_exec_command_index (current=0x55d41ab219f0, id=_SERVICE_EXEC_COMMAND_INVALID,
    u=0x55d41ab20980) at ../src/core/service.c:2442
#4  service_serialize_exec_command (u=u at entry=0x55d41ab20980, f=f at entry=0x55d41ac0cab0,
    command=0x55d41ab219f0) at ../src/core/service.c:2470
#5  0x000055d419ce7557 in service_serialize (u=0x55d41ab20980, f=0x55d41ac0cab0,
    fds=0x55d41ab59460) at ../src/core/service.c:2534
#6  0x000055d419cff0ed in unit_serialize (serialize_jobs=255, fds=0x55d41ab59460,
    f=0x55d41ac0cab0, u=0x55d41ab20980) at ../src/core/unit.h:582
#7  manager_serialize (m=0x55d41aaa54a0, f=<optimized out>, fds=0x55d41ab59460,
    switching_root=false) at ../src/core/manager.c:3208
#8  0x000055d419d3963d in manager_reload (m=0x55d41aaa54a0) at ../src/core/manager.c:3486
#9  invoke_main_loop (m=0x55d41aaa54a0, ret_reexecute=<optimized out>,
    ret_retval=<optimized out>, ret_shutdown_verb=0x7ffcecb91b48, ret_fds=0x7ffcecb91b38,
    ret_switch_root_dir=0x7ffcecb91b58, ret_switch_root_init=0x7ffcecb91b50,
    ret_error_message=0x7ffcecb91b40) at ../src/core/main.c:1873
#10 0x000055d419c91c06 in main (argc=1, argv=<optimized out>) at ../src/core/main.c:2625

Given "id=_SERVICE_EXEC_COMMAND_INVALID" in frame #3, this seems to
match the following reports:
https://bugzilla.redhat.com/show_bug.cgi?id=1829867
https://github.com/systemd/systemd/issues/15356

The problem in the above reports was fixed upstream in the following
pull request
https://github.com/systemd/systemd/pull/15546
and especially in commit
e9da62b18a core: make sure to restore the control command id, too (v246-rc1)

I've checked that there is no patch backporting this commit in the
latest version of the systemd package in Buster, 241-7~deb10u6. Would
you consider adding this commit?

Thank you
-Benjamin

-- Package-specific info:

-- System Information:
Debian Release: 10.5
  APT prefers stable
  APT policy: (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 4.19.0-cl-1-amd64 (SMP w/8 CPU cores)
Kernel taint flags: TAINT_OOT_MODULE
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages systemd depends on:
ii  adduser          3.118
ii  libacl1          2.2.53-4
ii  libapparmor1     2.13.2-10
ii  libaudit1        1:2.8.4-3
ii  libblkid1        2.33.1-0.1
ii  libc6            2.28-10
ii  libcap2          1:2.25-2
ii  libcryptsetup12  2:2.1.0-5+deb10u2
ii  libgcrypt20      1.8.4-5
ii  libgnutls30      3.6.7-4+deb10u5
ii  libgpg-error0    1.35-1
ii  libidn11         1.33-2.2
ii  libip4tc0        1.8.2-3-cl4u4.2.1
ii  libkmod2         26-1
ii  liblz4-1         1.8.3-1
ii  liblzma5         5.2.4-1
ii  libmount1        2.33.1-0.1
ii  libpam0g         1.3.1-5
ii  libseccomp2      2.3.3-4
ii  libselinux1      2.8-1+b1
ii  libsystemd0      241-7~deb10u4
ii  mount            2.33.1-0.1
ii  util-linux       2.33.1-0.1

Versions of packages systemd recommends:
ii  dbus            1.12.20-0+deb10u1
pn  libpam-systemd  <none>

Versions of packages systemd suggests:
pn  policykit-1        <none>
pn  systemd-container  <none>

Versions of packages systemd is related to:
pn  dracut           <none>
ii  initramfs-tools  0.133+deb10u1
ii  udev             241-7~deb10u4

-- Configuration Files:
/etc/systemd/system.conf changed [not included]

-- no debconf information