Re: pcap-dbus.o:undefined reference to `dbus_message_demarshal'

[Waqar Hameed]

On Tue, Mar 05, 2024 at 23:11 +0800 kernel test robot <lkp@xxxxxxxxx> wrote:

> Hi Vincent,
>
> FYI, the error/warning still remains.
>
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
> head:   90d35da658da8cff0d4ecbb5113f5fac9d00eb72
> commit: 10f4c9b9a33b7df000f74fa0d896351fb1a61e6a x86/asm: Fix build of UML with KASAN
> date:   6 months ago
> config: um-randconfig-r111-20240305 (https://download.01.org/0day-ci/archive/20240305/202403052336.y6DkUd8a-lkp@xxxxxxxxx/config)
> compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240305/202403052336.y6DkUd8a-lkp@xxxxxxxxx/reproduce)
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@xxxxxxxxx>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202403052336.y6DkUd8a-lkp@xxxxxxxxx/
>
> All errors (new ones prefixed by >>):
>
>    /usr/bin/ld: arch/um/drivers/pcap.o: in function `dbus_write':
>>> pcap-dbus.o:(.text+0x244ff): undefined reference to `dbus_message_demarshal'
>>> /usr/bin/ld: pcap-dbus.o:(.text+0x24515): undefined reference to `dbus_connection_send'
>>> /usr/bin/ld: pcap-dbus.o:(.text+0x2451e): undefined reference to `dbus_connection_flush'
>>> /usr/bin/ld: pcap-dbus.o:(.text+0x24526): undefined reference to `dbus_message_unref'
>>> /usr/bin/ld: pcap-dbus.o:(.text+0x24574): undefined reference to `dbus_error_free'
>    /usr/bin/ld: arch/um/drivers/pcap.o: in function `dbus_read':
>>> pcap-dbus.o:(.text+0x245c0): undefined reference to `dbus_connection_pop_message'
>>> /usr/bin/ld: pcap-dbus.o:(.text+0x245e2): undefined reference to `dbus_connection_pop_message'
>>> /usr/bin/ld: pcap-dbus.o:(.text+0x245f8): undefined reference to `dbus_connection_read_write'
>>> /usr/bin/ld: pcap-dbus.o:(.text+0x24662): undefined reference to `dbus_message_is_signal'
>>> /usr/bin/ld: pcap-dbus.o:(.text+0x2467e): undefined reference to `dbus_message_marshal'
>>> /usr/bin/ld: pcap-dbus.o:(.text+0x246e6): undefined reference to `dbus_free'
>    /usr/bin/ld: arch/um/drivers/pcap.o: in function `dbus_cleanup':
>>> pcap-dbus.o:(.text+0x2474c): undefined reference to `dbus_connection_unref'
>    /usr/bin/ld: arch/um/drivers/pcap.o: in function `dbus_activate':
>>> pcap-dbus.o:(.text+0x247f6): undefined reference to `dbus_connection_open'
>>> /usr/bin/ld: pcap-dbus.o:(.text+0x2480e): undefined reference to `dbus_bus_register'
>>> /usr/bin/ld: pcap-dbus.o:(.text+0x248fc): undefined reference to `dbus_bus_add_match'
>>> /usr/bin/ld: pcap-dbus.o:(.text+0x24904): undefined reference to `dbus_error_is_set'
>>> /usr/bin/ld: pcap-dbus.o:(.text+0x2494b): undefined reference to `dbus_bus_get'
>    /usr/bin/ld: pcap-dbus.o:(.text+0x2497c): undefined reference to `dbus_error_free'
>    /usr/bin/ld: pcap-dbus.o:(.text+0x2498d): undefined reference to `dbus_bus_add_match'
>    /usr/bin/ld: pcap-dbus.o:(.text+0x24995): undefined reference to `dbus_error_is_set'
>    /usr/bin/ld: pcap-dbus.o:(.text+0x249ce): undefined reference to `dbus_error_free'
>>> /usr/bin/ld: pcap-dbus.o:(.text+0x249da): undefined reference to `dbus_connection_unref'
>    /usr/bin/ld: pcap-dbus.o:(.text+0x24a06): undefined reference to `dbus_bus_get'
>    /usr/bin/ld: pcap-dbus.o:(.text+0x24a42): undefined reference to `dbus_error_free'
>>> /usr/bin/ld: pcap-dbus.o:(.text+0x24a55): undefined reference to `dbus_connection_set_max_received_size'
>    /usr/bin/ld: pcap-dbus.o:(.text+0x24a66): undefined reference to `dbus_connection_unref'
>    /usr/bin/ld: pcap-dbus.o:(.text+0x24adc): undefined reference to `dbus_error_free'
>    /usr/bin/ld: pcap-dbus.o:(.text+0x24b1a): undefined reference to `dbus_error_free'
>    collect2: error: ld returned 1 exit status

Hi Ingo!

This error seems to be unrelated to the reported commit 10f4c9b9a33b
("x86/asm: Fix build of UML with KASAN"). The root cause seems to be the
option `CONFIG_UML_NET_PCAP` (which is deprecated, as stated in
`arch/um/drivers/Kconfig`), which tries to build `pcap.o`. 

In the Makefile, one can find

  LDFLAGS_pcap.o = $(shell $(CC) $(KBUILD_CFLAGS) -print-file-name=libpcap.a)
  
and at the top the very old comment

 # pcap is broken in 2.5 because kbuild doesn't allow pcap.a to be linked
 # in to pcap.o

`libpcap` is indeed the one referencing these symbols (that can be found
in `libdbus-1` and `libsystemd`). I'm guessing we should just ignore
this report, right? (Can it even be disabled somehow?)

Thank you
Waqar Hameed

P.S 
Vincent has left the company and has therefore been removed from
the CC list.
D.S