Hi,

this seems to be a regression in Linux 6.15 (compared to 6.12, and IIRC
it didn't happen with 6.13 and 6.14 either). It affects the non-free dkms
modules that link some sourceless blobs into the kernel module.

For easier reproducibility I'm attaching the nvidia.o file (from the
340xx legacy driver, unreleased version from git) that was created with
  ld.bfd -m elf_x86_64 -z noexecstack --no-warn-rwx-segments   -r -o nvidia.o @nvidia.mod

Then I'm running the objtool step manually using objtool from 6.12 and
6.15 for comparison:

export SRCARCH=x86
cp nvidia.o nvidia615.o
cp nvidia.o nvidia612.o
/usr/src/linux-headers-6.12.32-amd64/tools/objtool/objtool --hacks=jump_label --hacks=noinstr --hacks=skylake --ibt --orc --retpoline --rethunk --sls --static-call --uaccess --prefix=16  --link  --module nvidia612.o
echo $?
/usr/src/linux-headers-6.15-amd64/tools/objtool/objtool --hacks=jump_label --hacks=noinstr --hacks=skylake --ibt --orc --retpoline --rethunk --sls --static-call --uaccess --prefix=16  --link  --module nvidia615.o
echo $?

The emitted diagnostics are the same in both cases, but objtool from
6.15 fails and does not modify the .o file:

+ export SRCARCH=x86
+ cp nvidia.o nvidia615.o
+ cp nvidia.o nvidia612.o
+ /usr/src/linux-headers-6.12.32-amd64/tools/objtool/objtool --hacks=jump_label --hacks=noinstr --hacks=skylake --ibt --orc --retpoline --rethunk --sls --static-call --uaccess --prefix=16 --link --module nvidia612.o
nvidia612.o: warning: objtool: .text+0xa34: unannotated intra-function call
+ echo 0
0
+ /usr/src/linux-headers-6.15-amd64/tools/objtool/objtool --hacks=jump_label --hacks=noinstr --hacks=skylake --ibt --orc --retpoline --rethunk --sls --static-call --uaccess --prefix=16 --link --module nvidia615.o
nvidia615.o: warning: objtool: .text+0xa34: unannotated intra-function call
+ echo 255
255

I don't know if src:sl-modem is affected as well, since some other
issues preventing module build with 6.15 need to be addressed first.
(#1106710)


Andreas