objtool: radeon_bo_list_validate+0x268: __stack_chk_fail() missing __noreturn in .c/.h or NORETURN() in noreturns.h

[nathanchance]

With several x86_64 distribution configurations:

$ curl -LSso .config https://gitlab.archlinux.org/archlinux/packaging/packages/linux/-/raw/main/config

$ make -skj"$(nproc)" ARCH=x86_64 LLVM=1 olddefconfig drivers/gpu/drm/radeon/radeon.o
...
drivers/gpu/drm/radeon/radeon.o: warning: objtool: radeon_bo_list_validate+0x260: __stack_chk_fail() missing __noreturn in .c/.h or NORETURN() in noreturns.h

With a simpler configuration, there is a different warning in this function.

$ cat allno.config
CONFIG_DRM=y
CONFIG_DRM_RADEON=m
CONFIG_MODULES=y
CONFIG_PCI=y

$ make -skj"$(nproc)" ARCH=x86_64 LLVM=1 clean allnoconfig drivers/gpu/drm/radeon/radeon.o
drivers/gpu/drm/radeon/radeon_object.o: warning: objtool: radeon_bo_list_validate+0x21b: unreachable instruction

[ernsteiswuerfel]

I got something similar for amdgpu on my ArrowLake Gentoo Linux Box (LLVM 21.1.3):

 # LLVM=1 make
  CALL    scripts/checksyscalls.sh
  DESCEND objtool
  INSTALL libsubcmd_headers
  LD [M]  drivers/gpu/drm/amd/amdgpu/amdgpu.o
drivers/gpu/drm/amd/amdgpu/amdgpu.o: error: objtool: amdgpu_cs_parser_bos+0x79b: unreachable instruction
make[6]: *** [scripts/Makefile.build:503: drivers/gpu/drm/amd/amdgpu/amdgpu.o] Error 1
make[6]: *** Deleting file 'drivers/gpu/drm/amd/amdgpu/amdgpu.o'
make[5]: *** [scripts/Makefile.build:556: drivers/gpu/drm/amd/amdgpu] Error 2
make[4]: *** [scripts/Makefile.build:556: drivers/gpu/drm] Error 2
make[3]: *** [scripts/Makefile.build:556: drivers/gpu] Error 2
make[2]: *** [scripts/Makefile.build:556: drivers] Error 2
make[1]: *** [/usr/src/linux-git/Makefile:2011: .] Error 2
make: *** [Makefile:248: __sub-make] Error 2

Happens on kernels v6.16.12 and v6.17.x. Last good one is v6.16.11.

Don't get this when building with GCC 15.2.0.

Kernel .config attached.
config_6172_arwl-clang21.txt

[nathanchance]

The radeon.o instance was introduced by llvm/llvm-project@4109bac according to my bisect.

[ernsteiswuerfel]

Do you perhaps have a commit to patch to revert this commit on top of 21.1.4 or 21.1.5? Could check out whether my issue with amdgpu would also be positively affected.

[ernsteiswuerfel]

Interestingly I don't get the build failure when I build my Thinkpad T60 (32bit Intel Core Solo, Mobility Radeon X1300) x86_32 kernel with radeon driver...

config_6177_p3.txt

[nathanchance]

Do you perhaps have a commit to patch to revert this commit on top of 21.1.4 or 21.1.5?

I think there was too much work on top of that change to easily revert it :/

I did file an issue upstream for this based on further examination and a cvise reduction: llvm/llvm-project#167774

[dileks]

With SLIM LLVM v21.1.7 from kernel.org I see this with Linux v6.18 Final:

$ grep warning: build-log_6.18.0-2-amd64-clang21-kcfi.txt | grep objtool:
drivers/gpu/drm/radeon/radeon.o: warning: objtool: radeon_bo_list_validate+0x260: __stack_chk_fail() missing __noreturn in .c/.h or NORETURN() in noreturns.h

[dileks]

With SLIM LLVM v21.1.7 from kernel.org I see this with Linux v6.19-rc1:

$ grep warning: build-log_6.19.0-rc1-1-amd64-clang21-kcfi.txt | grep objtool
drivers/gpu/drm/radeon/radeon.o: warning: objtool: radeon_bo_list_validate+0x260: __stack_chk_fail() missing __noreturn in .c/.h or NORETURN() in noreturns.h

[ernsteiswuerfel]

Interesting I only get this on x86_64. ppc64, ppc32 and also x86_32 build radeon fine.