Re: Bug#1120809: stress-ng FTCBFS for s390x: -fmodulo-sched is not removed
Hi Pranav,
On Thu, Nov 20, 2025 at 05:56:26AM +0000, Pranav P wrote:
> I tried performing a cross build from x86 for s390x with latest patch and it did appear to build fine.
Thank you!
> I also tested the cross built binary on an s390 machine.
I expect that if it built, it'll work.
> Are you still seeing this issue?
Yes. I can see it locally and I also observe it on QA infrastructure
https://crossqa.debian.net/src/stress-ng
Please bear in mind that the issue is related to performance. sbuild
aborts the build after 150 minutes of no output, so it really depends on
the speed of the machine performing the build. The ones I've been using
were aged x86 machines. Not the slowest, but also not very fast.
> If yes, could you please provide me some hints on how to reproduce this?
I suggest comparing compiler invocations. The buildds did this:
https://buildd.debian.org/status/fetch.php?pkg=stress-ng&arch=s390x&ver=0.19.06-3&stamp=1763035378&raw=1
| cc -g -O2 -Werror=implicit-function-declaration -ffile-prefix-map=/build/reproducible-path/stress-ng-0.19.06=. -fstack-protector-strong -Wformat -Werror=format-security -Wall -Wextra -DVERSION='"0.19.06"' -Wformat -fstack-protector-strong -Werror=format-security -D_FORTIFY_SOURCE=2 -fipa-pta -fivopts -ftree-vectorize -ftree-slp-vectorize -DHAVE_SOURCE_DATE_EPOCH=1763032064 -std=gnu99 -DHAVE_CFLAGS='"-g -O2 -Werror=implicit-function-declaration -ffile-prefix-map=/build/reproducible-path/stress-ng-0.19.06=. -fstack-protector-strong -Wformat -Werror=format-security -Wall -Wextra -DVERSION='"0.19.06"' -Wformat -fstack-protector-strong -Werror=format-security -D_FORTIFY_SOURCE=2 -fipa-pta -fivopts -ftree-vectorize -ftree-slp-vectorize -DHAVE_SOURCE_DATE_EPOCH=1763032064 -std=gnu99"' -DHAVE_LDFLAGS='"-Wl,-z,relro -Wl,-z,now"' -DHAVE_CXXFLAGS='"-g -O2 -ffile-prefix-map=/build/reproducible-path/stress-ng-0.19.06=. -fstack-protector-strong -Wformat -Werror=format-security -g -O2 -Werror=implicit-function-declaration -ffile-prefix-map=/build/reproducible-path/stress-ng-0.19.06=. -fstack-protector-strong -Wformat -Werror=format-security -Wall -Wextra -DVERSION='"0.19.06"' -Wformat -fstack-protector-strong -Werror=format-security -D_FORTIFY_SOURCE=2 -fipa-pta -fivopts -ftree-vectorize -ftree-slp-vectorize -DHAVE_SOURCE_DATE_EPOCH=1763032064"' -c -o stress-vecwide.o stress-vecwide.c
The cross buildd did this:
https://crossqa.debian.net/build/stress-ng_0.19.06-3_s390x_20251115213510.log
| s390x-linux-gnu-gcc -g -O2 -Werror=implicit-function-declaration -ffile-prefix-map=/<<PKGBUILDDIR>>=. -fstack-protector-strong -Wformat -Werror=format-security -Wall -Wextra -DVERSION='"0.19.06"' -Wformat -fstack-protector-strong -Werror=format-security -D_FORTIFY_SOURCE=2 -fipa-pta -fivopts -ftree-vectorize -ftree-slp-vectorize -fmodulo-sched -DHAVE_SOURCE_DATE_EPOCH=1763032064 -std=gnu99 -DHAVE_CFLAGS='"-g -O2 -Werror=implicit-function-declaration -ffile-prefix-map=/<<PKGBUILDDIR>>=. -fstack-protector-strong -Wformat -Werror=format-security -Wall -Wextra -DVERSION='"0.19.06"' -Wformat -fstack-protector-strong -Werror=format-security -D_FORTIFY_SOURCE=2 -fipa-pta -fivopts -ftree-vectorize -ftree-slp-vectorize -fmodulo-sched -DHAVE_SOURCE_DATE_EPOCH=1763032064 -std=gnu99"' -DHAVE_LDFLAGS='"-Wl,-z,relro -Wl,-z,now"' -DHAVE_CXXFLAGS='"-g -O2 -ffile-prefix-map=/<<PKGBUILDDIR>>=. -fstack-protector-strong -Wformat -Werror=format-security -g -O2 -Werror=implicit-function-declaration -ffile-prefix-map=/<<PKGBUILDDIR>>=. -fstack-protector-strong -Wformat -Werror=format-security -Wall -Wextra -DVERSION='"0.19.06"' -Wformat -fstack-protector-strong -Werror=format-security -D_FORTIFY_SOURCE=2 -fipa-pta -fivopts -ftree-vectorize -ftree-slp-vectorize -fmodulo-sched -DHAVE_SOURCE_DATE_EPOCH=1763032064"' -c -o stress-vecwide.o stress-vecwide.c
The changelog for -2 says:
| * Add fix to disable -fmodulo-sched for s390 systems to speed up
| very long build times.
Now we see the -fmodulo-sched option on the cross compiler invocation,
but not on the native one. How about your own cross builds?
Helmut
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