next-20250723 arm atags_to_fdt.c undefined reference to `__sanitizer_cov_stack_depth'

next-20250723 arm atags_to_fdt.c undefined reference to `__sanitizer_cov_stack_depth'

[Naresh Kamboju]

Regressions noticed while building arm builds with gcc-13 and gcc-8
toolchains on the Linux next-20250723 to next-20250725 tags.

First seen on the Linux next-20250723
Good: next-20250722
Bad:  next-20250723 and next-20250725

Regression Analysis:
- New regression? Yes
- Reproducibility? Yes

## Build regressions
* arm, build
  - gcc-13-lkftconfig-hardening
  - gcc-8-lkftconfig-hardening

Build regression: next-20250723 arm atags_to_fdt.c undefined reference
to `__sanitizer_cov_stack_depth'

Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>

## Build log
arm-linux-gnueabihf-ld: arch/arm/boot/compressed/atags_to_fdt.o: in
function `atags_to_fdt':
arch/arm/boot/compressed/atags_to_fdt.c:135:(.text+0x118): undefined
reference to `__sanitizer_cov_stack_depth'

## Source
* Git tree: https://kernel.googlesource.com/pub/scm/linux/kernel/git/next/linux-next.git
* Project: https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20250725/
* Git sha: d7af19298454ed155f5cf67201a70f5cf836c842
* Git describe: 6.16.0-rc7-next-20250725
* kernel version: next-20250723 next-20250725
* Architectures: arm
* Toolchains: gcc-8 gcc-13
* Kconfigs: hardening

## Test
* Test log: https://qa-reports.linaro.org/api/testruns/29244662/log_file/
* Test details:
https://regressions.linaro.org/lkft/linux-next-master/next-20250725/log-parser-build-gcc/general-ld-undefined-reference-undefined-reference-to-__sanitizer_cov_stack_depth/
* Test history:
https://qa-reports.linaro.org/lkft/linux-next-master/build/next-20250725/testrun/29244662/suite/build/test/gcc-13-lkftconfig-hardening/history/
* Test plan: https://tuxapi.tuxsuite.com/v1/groups/linaro/projects/lkft/builds/30LiHIefapv5cGlikeKrTz4lSKR
* Build link: https://storage.tuxsuite.com/public/linaro/lkft/builds/30LiHIefapv5cGlikeKrTz4lSKR/
* Kernel config:
https://storage.tuxsuite.com/public/linaro/lkft/builds/30LiHIefapv5cGlikeKrTz4lSKR/config

## steps to reproduce
   *  tuxmake --runtime podman --target-arch arm --toolchain gcc-13 \
              --kconfig defconfig --kconfig-add
https://gitlab.com/Linaro/lkft/kernel-fragments/-/raw/main/netdev.config
\
              --kconfig-add
https://gitlab.com/Linaro/lkft/kernel-fragments/-/raw/main/systemd.config
\
              --kconfig-add CONFIG_ARM_LPAE=y \
              --kconfig-add hardening.config

--
Linaro LKFT
https://lkft.linaro.org

Re: next-20250723 arm atags_to_fdt.c undefined reference to `__sanitizer_cov_stack_depth'

[Russell King (Oracle)]

On Fri, Jul 25, 2025 at 01:59:02PM +0530, Naresh Kamboju wrote:
> Regressions noticed while building arm builds with gcc-13 and gcc-8
> toolchains on the Linux next-20250723 to next-20250725 tags.
> 
> First seen on the Linux next-20250723
> Good: next-20250722
> Bad:  next-20250723 and next-20250725
> 
> Regression Analysis:
> - New regression? Yes
> - Reproducibility? Yes
> 
> ## Build regressions
> * arm, build
>   - gcc-13-lkftconfig-hardening
>   - gcc-8-lkftconfig-hardening
> 
> Build regression: next-20250723 arm atags_to_fdt.c undefined reference
> to `__sanitizer_cov_stack_depth'

"cov" suggests "coverty", and that the symbol is not available in the
kernel suggests that coverty isn't supported.

Maybe some kind of new support has been added, but no one has told the
arm developers, and thus bits needed for it aren't present.

Honestly, I'm not going to worry about it. If someone wishes to
contribute 32-bit arm support, then fine, otherwise I'll just ignore
this.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!

Re: next-20250723 arm atags_to_fdt.c undefined reference to `__sanitizer_cov_stack_depth'

[Kees Cook]

On Fri, Jul 25, 2025 at 10:07:24AM +0100, Russell King (Oracle) wrote:
> On Fri, Jul 25, 2025 at 01:59:02PM +0530, Naresh Kamboju wrote:
> > Regressions noticed while building arm builds with gcc-13 and gcc-8
> > toolchains on the Linux next-20250723 to next-20250725 tags.
> > 
> > First seen on the Linux next-20250723
> > Good: next-20250722
> > Bad:  next-20250723 and next-20250725
> > 
> > Regression Analysis:
> > - New regression? Yes
> > - Reproducibility? Yes
> > 
> > ## Build regressions
> > * arm, build
> >   - gcc-13-lkftconfig-hardening
> >   - gcc-8-lkftconfig-hardening
> > 
> > Build regression: next-20250723 arm atags_to_fdt.c undefined reference
> > to `__sanitizer_cov_stack_depth'
> 
> "cov" suggests "coverty", and that the symbol is not available in the
> kernel suggests that coverty isn't supported.

This is the coverage sanitizer and related to my changes. Sorry! This
didn't show up in my build testing, I'll reproduce it and get it fixed.

-- 
Kees Cook