Comment # 1 on bug 1168910 from Larry Finger

I no longer had kernel 5.5.13 available, thus I downloaded 5.5.16 from the
Kernel Archives and built it. That should not make a difference, nor should my
getting a mainline kernel source instead of from openSUSE.

My results were:

finger@linux-n6zm:/usr/src/kernel-modules/virtualbox/src> sudo make
=== Building 'vboxdrv' module ===
make[1]: Entering directory '/usr/src/kernel-modules/virtualbox/src/vboxdrv'
make V= CONFIG_MODULE_SIG= CONFIG_MODULE_SIG_ALL= -C /lib/modules/5.5.16/build
M=/usr/src/kernel-modules/virtualbox/src/vboxdrv
SRCROOT=/usr/src/kernel-modules/virtualbox/src/vboxdrv -j4 modules
make[2]: Entering directory '/home/finger/linux-5.5.16'
  CC [M]  /usr/src/kernel-modules/virtualbox/src/vboxdrv/linux/SUPDrv-linux.o
  CC [M]  /usr/src/kernel-modules/virtualbox/src/vboxdrv/SUPDrv.o
  CC [M]  /usr/src/kernel-modules/virtualbox/src/vboxdrv/SUPDrvGip.o
  CC [M]  /usr/src/kernel-modules/virtualbox/src/vboxdrv/SUPDrvSem.o
In file included from
/usr/src/kernel-modules/virtualbox/src/vboxdrv/SUPDrvGip.c:59:
/usr/src/kernel-modules/virtualbox/src/vboxdrv/include/iprt/x86.h:843: warning:
"X86_CR0_PE" redefined
  843 | #define X86_CR0_PE                          RT_BIT_32(0)
      | 
In file included from ./arch/x86/include/asm/processor-flags.h:5,
                 from ./arch/x86/include/asm/processor.h:5,
                 from ./arch/x86/include/asm/cpufeature.h:5,
                 from ./arch/x86/include/asm/thread_info.h:53,
                 from ./include/linux/thread_info.h:38,
                 from ./arch/x86/include/asm/preempt.h:7,
                 from ./include/linux/preempt.h:78,
                 from ./include/linux/spinlock.h:51,
                 from ./include/linux/seqlock.h:36,
                 from ./include/linux/time.h:6,
                 from ./include/linux/ktime.h:24,
                 from
/usr/src/kernel-modules/virtualbox/src/vboxdrv/include/iprt/time.h:44,
                 from
/usr/src/kernel-modules/virtualbox/src/vboxdrv/SUPDrvInternal.h:44,
                 from
/usr/src/kernel-modules/virtualbox/src/vboxdrv/SUPDrvGip.c:33:
./arch/x86/include/uapi/asm/processor-flags.h:52: note: this is the location of
the previous definition
   52 | #define X86_CR0_PE  _BITUL(X86_CR0_PE_BIT)
      | 
In file included from
/usr/src/kernel-modules/virtualbox/src/vboxdrv/SUPDrv.c:62:
/usr/src/kernel-modules/virtualbox/src/vboxdrv/include/iprt/x86.h:843: warning:
"X86_CR0_PE" redefined
  843 | #define X86_CR0_PE                          RT_BIT_32(0)
      | 
In file included from ./arch/x86/include/asm/processor-flags.h:5,
                 from ./arch/x86/include/asm/processor.h:5,
                 from ./arch/x86/include/asm/cpufeature.h:5,
                 from ./arch/x86/include/asm/thread_info.h:53,
                 from ./include/linux/thread_info.h:38,
                 from ./arch/x86/include/asm/preempt.h:7,
                 from ./include/linux/preempt.h:78,
                 from ./include/linux/spinlock.h:51,
                 from ./include/linux/seqlock.h:36,
                 from ./include/linux/time.h:6,
                 from ./include/linux/ktime.h:24,
                 from
/usr/src/kernel-modules/virtualbox/src/vboxdrv/include/iprt/time.h:44,
                 from
/usr/src/kernel-modules/virtualbox/src/vboxdrv/SUPDrvInternal.h:44,
                 from
/usr/src/kernel-modules/virtualbox/src/vboxdrv/SUPDrv.c:33:
./arch/x86/include/uapi/asm/processor-flags.h:52: note: this is the location of
the previous definition
   52 | #define X86_CR0_PE  _BITUL(X86_CR0_PE_BIT)
      | 

-- snip --

=== Building 'vboxnetadp' module ===
make[1]: Entering directory '/usr/src/kernel-modules/virtualbox/src/vboxnetadp'
make V= CONFIG_MODULE_SIG= CONFIG_MODULE_SIG_ALL= -C /lib/modules/5.5.16/build
M=/usr/src/kernel-modules/virtualbox/src/vboxnetadp
SRCROOT=/usr/src/kernel-modules/virtualbox/src/vboxnetadp -j4 modules
make[2]: Entering directory '/home/finger/linux-5.5.16'
  CC [M] 
/usr/src/kernel-modules/virtualbox/src/vboxnetadp/linux/VBoxNetAdp-linux.o
  CC [M]  /usr/src/kernel-modules/virtualbox/src/vboxnetadp/VBoxNetAdp.o
  LD [M]  /usr/src/kernel-modules/virtualbox/src/vboxnetadp/vboxnetadp.o
  Building modules, stage 2.
  MODPOST 1 modules
  CC [M]  /usr/src/kernel-modules/virtualbox/src/vboxnetadp/vboxnetadp.mod.o
  LD [M]  /usr/src/kernel-modules/virtualbox/src/vboxnetadp/vboxnetadp.ko
make[2]: Leaving directory '/home/finger/linux-5.5.16'
make[1]: Leaving directory '/usr/src/kernel-modules/virtualbox/src/vboxnetadp'

finger@linux-n6zm:/usr/src/kernel-modules/virtualbox/src> uname -r
5.5.16

As you see, it built correctly. I am working at preparing patches to eliminate
all those warnings, but that job has a very low probability.

There is a bug in the current Makefile, but it leads to a very different error
than what you are reporting. There is the following sequence:

vboxnetadp: vboxdrv
        @if [ -d vboxnetadp ]; then \
            if [ -f vboxdrv/Module.symvers ]; then \
                cp vboxdrv/Module.symvers vboxnetadp; \
            fi; \
            export KBUILD_EXTRA_SYMBOLS=${PWD}/vboxnetadp/Module.symvers; \
            echo "=== Building 'vboxnetadp' module ==="; \
            $(MAKE) KBUILD_VERBOSE=$(KBUILD_VERBOSE)
KBUILD_EXTRA_SYMBOLS=$(abspath vboxpci/Module.symvers) -C vboxnetadp || exit 1;
\
            cp vboxnetadp/vboxnetadp.ko .; \
            echo; \
        fi

The "vboxpci" in the $(MAKE) line should be "vboxdrv". With that change, which
has been submitted to Factory, the kernel modules build correctly.

It is possible that the above bug is leading to different errors on your system
than mine. Please check Makefile in /usr/src/kernel-modules/virtualbox/src/ for
that problem and report what you find.