../src/basic/log.h:107:9: error: ‘%s’ directive argument is null [-Werror=format-overflow=]

[mbiebl]

I'm getting build failures with systemd master (641aa41)

So far I can only reproduce it when building with -Db_lto=false

$ gcc --version
gcc (Debian 9.2.1-28) 9.2.1 20200203
Copyright (C) 2019 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

$ ld --version
GNU ld (GNU Binutils for Debian) 2.34
Copyright (C) 2020 Free Software Foundation, Inc.
This program is free software; you may redistribute it under the terms of
the GNU General Public License version 3 or (at your option) a later version.
This program has absolutely no warranty.

[536/1910] cc -Isrc/network/70b1c79@@networkd-core@sta -Isrc/network -I../src/network -Isrc/basic -I../src/basic -Isrc/boot -I../src/boot -Isrc/shared -I../src/shared -Isrc/systemd -I../src/systemd -Isrc/journal -I../src/journal -Isrc/journal-remote -I../src/journal-remote -Isrc/nspawn -I../src/nspawn -Isrc/resolve -I../src/resolve -Isrc/timesync -I../src/timesync -I../src/time-wait-sync -Isrc/login -I../src/login -Isrc/udev -I../src/udev -Isrc/libudev -I../src/libudev -Isrc/core -I../src/core -Isrc/shutdown -I../src/shutdown -I../src/libsystemd/sd-bus -I../src/libsystemd/sd-device -I../src/libsystemd/sd-event -I../src/libsystemd/sd-hwdb -I../src/libsystemd/sd-id128 -I../src/libsystemd/sd-netlink -I../src/libsystemd/sd-network -I../src/libsystemd/sd-resolve -Isrc/libsystemd-network -I../src/libsystemd-network -I. -I../ -I../src/network/netdev -I../src/network/tc -fdiagnostics-color=always -pipe -D_FILE_OFFSET_BITS=64 -std=gnu99 -Wno-unused-parameter -Wno-missing-field-initializers -Wno-unused-result -Wno-format-signedness -Werror=undef -Wlogical-op -Wmissing-include-dirs -Wold-style-definition -Wpointer-arith -Winit-self -Wfloat-equal -Wsuggest-attribute=noreturn -Werror=missing-prototypes -Werror=implicit-function-declaration -Werror=missing-declarations -Werror=return-type -Werror=incompatible-pointer-types -Werror=format=2 -Wstrict-prototypes -Wredundant-decls -Wmissing-noreturn -Wimplicit-fallthrough=5 -Wshadow -Wendif-labels -Wstrict-aliasing=2 -Wwrite-strings -Werror=overflow -Werror=shift-count-overflow -Werror=shift-overflow=2 -Wdate-time -Wnested-externs -Wno-error=nonnull -Wno-maybe-uninitialized -ffast-math -fno-common -fdiagnostics-show-option -fno-strict-aliasing -fvisibility=hidden -fstack-protector -fstack-protector-strong --param=ssp-buffer-size=4 -ffunction-sections -fdata-sections -Werror=shadow -include config.h -g -O2 -fdebug-prefix-map=/home/michael/git/systemd=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -fPIC -MD -MQ 'src/network/70b1c79@@networkd-core@sta/networkd-dhcp-server.c.o' -MF 'src/network/70b1c79@@networkd-core@sta/networkd-dhcp-server.c.o.d' -o 'src/network/70b1c79@@networkd-core@sta/networkd-dhcp-server.c.o' -c ../src/network/networkd-dhcp-server.c
FAILED: src/network/70b1c79@@networkd-core@sta/networkd-dhcp-server.c.o 
cc -Isrc/network/70b1c79@@networkd-core@sta -Isrc/network -I../src/network -Isrc/basic -I../src/basic -Isrc/boot -I../src/boot -Isrc/shared -I../src/shared -Isrc/systemd -I../src/systemd -Isrc/journal -I../src/journal -Isrc/journal-remote -I../src/journal-remote -Isrc/nspawn -I../src/nspawn -Isrc/resolve -I../src/resolve -Isrc/timesync -I../src/timesync -I../src/time-wait-sync -Isrc/login -I../src/login -Isrc/udev -I../src/udev -Isrc/libudev -I../src/libudev -Isrc/core -I../src/core -Isrc/shutdown -I../src/shutdown -I../src/libsystemd/sd-bus -I../src/libsystemd/sd-device -I../src/libsystemd/sd-event -I../src/libsystemd/sd-hwdb -I../src/libsystemd/sd-id128 -I../src/libsystemd/sd-netlink -I../src/libsystemd/sd-network -I../src/libsystemd/sd-resolve -Isrc/libsystemd-network -I../src/libsystemd-network -I. -I../ -I../src/network/netdev -I../src/network/tc -fdiagnostics-color=always -pipe -D_FILE_OFFSET_BITS=64 -std=gnu99 -Wno-unused-parameter -Wno-missing-field-initializers -Wno-unused-result -Wno-format-signedness -Werror=undef -Wlogical-op -Wmissing-include-dirs -Wold-style-definition -Wpointer-arith -Winit-self -Wfloat-equal -Wsuggest-attribute=noreturn -Werror=missing-prototypes -Werror=implicit-function-declaration -Werror=missing-declarations -Werror=return-type -Werror=incompatible-pointer-types -Werror=format=2 -Wstrict-prototypes -Wredundant-decls -Wmissing-noreturn -Wimplicit-fallthrough=5 -Wshadow -Wendif-labels -Wstrict-aliasing=2 -Wwrite-strings -Werror=overflow -Werror=shift-count-overflow -Werror=shift-overflow=2 -Wdate-time -Wnested-externs -Wno-error=nonnull -Wno-maybe-uninitialized -ffast-math -fno-common -fdiagnostics-show-option -fno-strict-aliasing -fvisibility=hidden -fstack-protector -fstack-protector-strong --param=ssp-buffer-size=4 -ffunction-sections -fdata-sections -Werror=shadow -include config.h -g -O2 -fdebug-prefix-map=/home/michael/git/systemd=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -fPIC -MD -MQ 'src/network/70b1c79@@networkd-core@sta/networkd-dhcp-server.c.o' -MF 'src/network/70b1c79@@networkd-core@sta/networkd-dhcp-server.c.o.d' -o 'src/network/70b1c79@@networkd-core@sta/networkd-dhcp-server.c.o' -c ../src/network/networkd-dhcp-server.c
In file included from ../src/basic/macro.h:586,
                 from ../src/basic/alloc-util.h:9,
                 from ../src/shared/conf-parser.h:10,
                 from ../src/network/networkd-dhcp-server.h:4,
                 from ../src/network/networkd-dhcp-server.c:5:
In function ‘link_push_uplink_dns_to_dhcp_server’,
    inlined from ‘dhcp4_server_configure’ at ../src/network/networkd-dhcp-server.c:242:37:
../src/basic/log.h:107:9: error: ‘%s’ directive argument is null [-Werror=format-overflow=]
  107 |         log_internal_realm(LOG_REALM_PLUS_LEVEL(LOG_REALM, (level)), __VA_ARGS__)
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../src/shared/log-link.h:21:25: note: in expansion of macro ‘log_internal’
   21 |                         log_internal(level, error, PROJECT_FILE, __LINE__, __func__, ##__VA_ARGS__); \
      |                         ^~~~~~~~~~~~
../src/shared/log-link.h:24:37: note: in expansion of macro ‘log_link_full’
   24 | #define log_link_debug(link, ...)   log_link_full(link, LOG_DEBUG, 0, ##__VA_ARGS__)
      |                                     ^~~~~~~~~~~~~
../src/network/networkd-dhcp-server.c:48:9: note: in expansion of macro ‘log_link_debug’
   48 |         log_link_debug(link, "Copying DNS server information from %s", link->ifname);
      |         ^~~~~~~~~~~~~~
../src/network/networkd-dhcp-server.c: In function ‘dhcp4_server_configure’:
../src/network/networkd-dhcp-server.c:48:67: note: format string is defined here
   48 |         log_link_debug(link, "Copying DNS server information from %s", link->ifname);
      |                                                                   ^~
In file included from ../src/basic/macro.h:586,
                 from ../src/basic/alloc-util.h:9,
                 from ../src/shared/conf-parser.h:10,
                 from ../src/network/networkd-dhcp-server.h:4,
                 from ../src/network/networkd-dhcp-server.c:5:
In function ‘link_push_uplink_ntp_to_dhcp_server’,
    inlined from ‘dhcp4_server_configure’ at ../src/network/networkd-dhcp-server.c:259:37:
../src/basic/log.h:107:9: error: ‘%s’ directive argument is null [-Werror=format-overflow=]
  107 |         log_internal_realm(LOG_REALM_PLUS_LEVEL(LOG_REALM, (level)), __VA_ARGS__)
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../src/shared/log-link.h:21:25: note: in expansion of macro ‘log_internal’
   21 |                         log_internal(level, error, PROJECT_FILE, __LINE__, __func__, ##__VA_ARGS__); \
      |                         ^~~~~~~~~~~~
../src/shared/log-link.h:24:37: note: in expansion of macro ‘log_link_full’
   24 | #define log_link_debug(link, ...)   log_link_full(link, LOG_DEBUG, 0, ##__VA_ARGS__)
      |                                     ^~~~~~~~~~~~~
../src/network/networkd-dhcp-server.c:102:9: note: in expansion of macro ‘log_link_debug’
  102 |         log_link_debug(link, "Copying NTP server information from %s", link->ifname);
      |         ^~~~~~~~~~~~~~
../src/network/networkd-dhcp-server.c: In function ‘dhcp4_server_configure’:
../src/network/networkd-dhcp-server.c:102:67: note: format string is defined here
  102 |         log_link_debug(link, "Copying NTP server information from %s", link->ifname);
      |                                                                   ^~
In file included from ../src/basic/macro.h:586,
                 from ../src/basic/alloc-util.h:9,
                 from ../src/shared/conf-parser.h:10,
                 from ../src/network/networkd-dhcp-server.h:4,
                 from ../src/network/networkd-dhcp-server.c:5:
In function ‘link_push_uplink_sip_to_dhcp_server’,
    inlined from ‘dhcp4_server_configure’ at ../src/network/networkd-dhcp-server.c:277:37:
../src/basic/log.h:107:9: error: ‘%s’ directive argument is null [-Werror=format-overflow=]
  107 |         log_internal_realm(LOG_REALM_PLUS_LEVEL(LOG_REALM, (level)), __VA_ARGS__)
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../src/shared/log-link.h:21:25: note: in expansion of macro ‘log_internal’
   21 |                         log_internal(level, error, PROJECT_FILE, __LINE__, __func__, ##__VA_ARGS__); \
      |                         ^~~~~~~~~~~~
../src/shared/log-link.h:24:37: note: in expansion of macro ‘log_link_full’
   24 | #define log_link_debug(link, ...)   log_link_full(link, LOG_DEBUG, 0, ##__VA_ARGS__)
      |                                     ^~~~~~~~~~~~~
../src/network/networkd-dhcp-server.c:151:9: note: in expansion of macro ‘log_link_debug’
  151 |         log_link_debug(link, "Copying SIP server information from %s", link->ifname);
      |         ^~~~~~~~~~~~~~
../src/network/networkd-dhcp-server.c: In function ‘dhcp4_server_configure’:
../src/network/networkd-dhcp-server.c:151:67: note: format string is defined here
  151 |         log_link_debug(link, "Copying SIP server information from %s", link->ifname);
      |                                                                   ^~
cc1: some warnings being treated as errors

Full build log is attached, where you can see all configure switches.

[mbiebl]

build.txt