gcc-12 seems to be unhappy about mfree()

[mrc0mmand]

systemd version the issue has been seen with

latest master

Used distribution

Fedora Rawhide (gcc-12)

Recent Packit jobs fail with:

In file included from ../src/basic/macro.h:12,
                 from ../src/basic/time-util.h:19,
                 from ../src/shared/ask-password-api.h:6,
                 from ../src/shared/pkcs11-util.c:5:
In function ‘freep’,
    inlined from ‘pkcs11_token_login’ at ../src/shared/pkcs11-util.c:240:83:
../src/fundamental/macro-fundamental.h:284:17: error: pointer ‘id_384’ used after ‘free’ [-Werror=use-after-free]
  284 |                 free(memory);                   \
      |                 ^~~~~~~~~~~~
In function ‘freep’,
    inlined from ‘pkcs11_token_login’ at ../src/shared/pkcs11-util.c:240:95:
../src/fundamental/macro-fundamental.h:284:17: note: call to ‘free’ here
  284 |                 free(memory);                   \
      |                 ^~~~~~~~~~~~
In function ‘freep’,
    inlined from ‘pkcs11_token_login’ at ../src/shared/pkcs11-util.c:240:56:
../src/fundamental/macro-fundamental.h:284:17: error: pointer ‘token_uri_escaped_380’ used after ‘free’ [-Werror=use-after-free]
  284 |                 free(memory);                   \
      |                 ^~~~~~~~~~~~
In function ‘freep’,
    inlined from ‘pkcs11_token_login’ at ../src/shared/pkcs11-util.c:240:95:
../src/fundamental/macro-fundamental.h:284:17: note: call to ‘free’ here
  284 |                 free(memory);                   \
      |                 ^~~~~~~~~~~~
cc1: all warnings being treated as errors

regarding

systemd/src/fundamental/macro-fundamental.h

Lines 282 to 287 in f939a89

	#define mfree(memory) \
	({ \
	free(memory); \
	(typeof(memory)) NULL; \
	})

[mrc0mmand]

Given that clang-12 and clang-13 seem to be alright with this, I'd say it's an issue on gcc's side, but I tagged as "bug" just to be sure...

[yuwata]

I'd like to tag this 'not-our-bug' :-)

[yuwata]

C.f. #22191.

[mrc0mmand]

C.f. #22191.

Ah, I had a feeling I've seen it before :-) I'll try to dig a bit deeper and report it to gcc folks, if possible.

[bluca]

Can we add a pragma to ignore it?

[mrc0mmand]

Interesting, the culprit seems to be -ffat-lto-objects when used with gcc-12 (and this option is added to $CFLAGS by rpm's hardening macros.

# cc -Isrc/shared/libsystemd-shared-250.a.p -Isrc/shared -I../src/shared -Isrc/basic -I../src/basic -Isrc/fundamental -I../src/fundamental -Isrc/systemd -I../src/systemd -I. -I.. -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-journal -I../src/libsystemd/sd-netlink -I../src/libsystemd/sd-network -I../src/libsystemd/sd-resolve -I/usr/include/blkid -I/usr/include/libmount -I/usr/include/p11-kit-1 -fdiagnostics-color=always -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Wextra -Werror -std=gnu99 -g -Wno-format-signedness -Wno-missing-field-initializers -Wno-unused-parameter -Wdate-time -Wendif-labels -Werror=format=2 -Werror=implicit-function-declaration -Werror=incompatible-pointer-types -Werror=int-conversion -Werror=overflow -Werror=override-init -Werror=return-type -Werror=shift-count-overflow -Werror=shift-overflow=2 -Werror=undef -Wfloat-equal -Wimplicit-fallthrough=5 -Winit-self -Wlogical-op -Wmissing-include-dirs -Wmissing-noreturn -Wnested-externs -Wold-style-definition -Wpointer-arith -Wredundant-decls -Wshadow -Wstrict-aliasing=2 -Wstrict-prototypes -Wsuggest-attribute=noreturn -Wunused-function -Wwrite-strings -Wno-unused-result -Werror=missing-declarations -Werror=missing-prototypes -fdiagnostics-show-option -fno-common -fno-strict-aliasing -fstack-protector -fstack-protector-strong -fvisibility=hidden --param=ssp-buffer-size=4 -Werror=shadow -include config.h -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -fPIC -pthread -fvisibility=default -MD -MQ src/shared/libsystemd-shared-250.a.p/pkcs11-util.c.o -MF src/shared/libsystemd-shared-250.a.p/pkcs11-util.c.o.d -o src/shared/libsystemd-shared-250.a.p/pkcs11-util.c.o -c ../src/shared/pkcs11-util.c 
In file included from ../src/basic/macro.h:12,
                 from ../src/basic/time-util.h:19,
                 from ../src/shared/ask-password-api.h:6,
                 from ../src/shared/pkcs11-util.c:5:
In function ‘freep’,
    inlined from ‘pkcs11_token_login’ at ../src/shared/pkcs11-util.c:240:83:
../src/fundamental/macro-fundamental.h:284:17: error: pointer ‘id_390’ used after ‘free’ [-Werror=use-after-free]
  284 |                 free(memory);                   \
      |                 ^~~~~~~~~~~~
In function ‘freep’,
    inlined from ‘pkcs11_token_login’ at ../src/shared/pkcs11-util.c:240:95:
../src/fundamental/macro-fundamental.h:284:17: note: call to ‘free’ here
  284 |                 free(memory);                   \
      |                 ^~~~~~~~~~~~
In function ‘freep’,
    inlined from ‘pkcs11_token_login’ at ../src/shared/pkcs11-util.c:240:56:
../src/fundamental/macro-fundamental.h:284:17: error: pointer ‘token_uri_escaped_386’ used after ‘free’ [-Werror=use-after-free]
  284 |                 free(memory);                   \
      |                 ^~~~~~~~~~~~
In function ‘freep’,
    inlined from ‘pkcs11_token_login’ at ../src/shared/pkcs11-util.c:240:95:
../src/fundamental/macro-fundamental.h:284:17: note: call to ‘free’ here
  284 |                 free(memory);                   \
      |                 ^~~~~~~~~~~~
cc1: all warnings being treated as errors

with -fno-fat-lto-objects appended:

# cc -Isrc/shared/libsystemd-shared-250.a.p -Isrc/shared -I../src/shared -Isrc/basic -I../src/basic -Isrc/fundamental -I../src/fundamental -Isrc/systemd -I../src/systemd -I. -I.. -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-journal -I../src/libsystemd/sd-netlink -I../src/libsystemd/sd-network -I../src/libsystemd/sd-resolve -I/usr/include/blkid -I/usr/include/libmount -I/usr/include/p11-kit-1 -fdiagnostics-color=always -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Wextra -Werror -std=gnu99 -g -Wno-format-signedness -Wno-missing-field-initializers -Wno-unused-parameter -Wdate-time -Wendif-labels -Werror=format=2 -Werror=implicit-function-declaration -Werror=incompatible-pointer-types -Werror=int-conversion -Werror=overflow -Werror=override-init -Werror=return-type -Werror=shift-count-overflow -Werror=shift-overflow=2 -Werror=undef -Wfloat-equal -Wimplicit-fallthrough=5 -Winit-self -Wlogical-op -Wmissing-include-dirs -Wmissing-noreturn -Wnested-externs -Wold-style-definition -Wpointer-arith -Wredundant-decls -Wshadow -Wstrict-aliasing=2 -Wstrict-prototypes -Wsuggest-attribute=noreturn -Wunused-function -Wwrite-strings -Wno-unused-result -Werror=missing-declarations -Werror=missing-prototypes -fdiagnostics-show-option -fno-common -fno-strict-aliasing -fstack-protector -fstack-protector-strong -fvisibility=hidden --param=ssp-buffer-size=4 -Werror=shadow -include config.h -O2 -flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection -fPIC -pthread -fvisibility=default -MD -MQ src/shared/libsystemd-shared-250.a.p/pkcs11-util.c.o -MF src/shared/libsystemd-shared-250.a.p/pkcs11-util.c.o.d -o src/shared/libsystemd-shared-250.a.p/pkcs11-util.c.o -c ../src/shared/pkcs11-util.c -fno-fat-lto-objects
# echo $?
0

[mrc0mmand]

Filed as https://bugzilla.redhat.com/show_bug.cgi?id=2043915.