Um 19:28 Uhr am 19.10.20 schrieb Sven Hartge: > What?! > > I tested with debsums -c and even reinstalled > linux-headers-5.9.0-1-common, comparing the before and after, nothing > broken, nothing missing.
Scratch that last part. Because make did run correctly during gen_compat_def it wasn't recompiling the test code outside of it because of the timestamp. Removing "-s" and adding "-B" to make make more talkative and force it to compile stuff helps. But: Then the problem disappears: Working system: ---------8<----------- # make -B -C /lib/modules/5.9.0-1-amd64/build M=/var/lib/dkms/ipt-netflow/2.5.1/source/cc-test-build modules make: Entering directory '/usr/src/linux-headers-5.9.0-1-amd64' CC [M] /var/lib/dkms/ipt-netflow/2.5.1/source/cc-test-build/test.o /var/lib/dkms/ipt-netflow/2.5.1/source/cc-test-build/test.c:4:16: error: storage size of 'test' isn't known 4 | struct timeval test; | ^~~~ make[2]: *** [/usr/src/linux-headers-5.9.0-1-common/scripts/Makefile.build:288: /var/lib/dkms/ipt-netflow/2.5.1/source/cc-test-build/test.o] Error 1 make[1]: *** [/usr/src/linux-headers-5.9.0-1-common/Makefile:1796: /var/lib/dkms/ipt-netflow/2.5.1/source/cc-test-build] Error 2 make: *** [/usr/src/linux-headers-5.9.0-1-common/Makefile:185: __sub-make] Error 2 make: Leaving directory '/usr/src/linux-headers-5.9.0-1-amd64' ---------8<----------- Broken system: ---------8<----------- # make -B -C /lib/modules/5.9.0-1-amd64/build M=/var/lib/dkms/ipt-netflow/2.5.1/source/cc-test-build modules make: Entering directory '/usr/src/linux-headers-5.9.0-1-amd64' CC [M] /var/lib/dkms/ipt-netflow/2.5.1/source/cc-test-build/test.o /var/lib/dkms/ipt-netflow/2.5.1/source/cc-test-build/test.c:4:16: error: storage size of 'test' isn't known 4 | struct timeval test; | ^~~~ make[2]: *** [/usr/src/linux-headers-5.9.0-1-common/scripts/Makefile.build:288: /var/lib/dkms/ipt-netflow/2.5.1/source/cc-test-build/test.o] Error 1 make[1]: *** [/usr/src/linux-headers-5.9.0-1-common/Makefile:1796: /var/lib/dkms/ipt-netflow/2.5.1/source/cc-test-build] Error 2 make: *** [/usr/src/linux-headers-5.9.0-1-common/Makefile:185: __sub-make] Error 2 make: Leaving directory '/usr/src/linux-headers-5.9.0-1-amd64' ---------8<----------- Why is compiling the test code inside gen_compat_def behaving differently than outside of it? I have already compared the environment variables and cannot find anything relevant. There are no strange LD_* or CLFAGS set globally, no distcc or ccache remnants. My brain hurts. Grüße, Sven.