Re: linux-next: manual merge of the net-next tree with the kbuild tree

On Thu, Aug 15, 2019 at 10:21:29PM -0700, Andrii Nakryiko wrote:

On Thu, Aug 15, 2019 at 7:42 PM Stephen Rothwell [off-list ref] wrote:

quoted

Hi all,

Today's linux-next merge of the net-next tree got a conflict in:

  scripts/link-vmlinux.sh

between commit:

  e167191e4a8a ("kbuild: Parameterize kallsyms generation and correct reporting")

from the kbuild tree and commits:

  341dfcf8d78e ("btf: expose BTF info through sysfs")
  7fd785685e22 ("btf: rename /sys/kernel/btf/kernel into /sys/kernel/btf/vmlinux")

from the net-next tree.

I fixed it up (I think - see below) and can carry the fix as necessary.

Thanks, Stephen! Looks good except one minor issue below.

quoted

This is now fixed as far as linux-next is concerned, but any non trivial
conflicts should be mentioned to your upstream maintainer when your tree
is submitted for merging.  You may also want to consider cooperating
with the maintainer of the conflicting tree to minimise any particularly
complex conflicts.

--
Cheers,
Stephen Rothwell

diff --cc scripts/link-vmlinux.sh
index 2438a9faf3f1,c31193340108..000000000000

--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh

@@@ -56,11 -56,10 +56,11 @@@ modpost_link(
  }

  # Link of vmlinux
- # ${1} - optional extra .o files
- # ${2} - output file
+ # ${1} - output file
+ # ${@:2} - optional extra .o files
  vmlinux_link()
  {
 +      info LD ${2}

This needs to be ${1}.

quoted

        local lds="${objtree}/${KBUILD_LDS}"
        local objects

@@@ -139,18 -149,6 +150,18 @@@ kallsyms(
        ${CC} ${aflags} -c -o ${2} ${afile}
  }

 +# Perform one step in kallsyms generation, including temporary linking of
 +# vmlinux.
 +kallsyms_step()
 +{
 +      kallsymso_prev=${kallsymso}
 +      kallsymso=.tmp_kallsyms${1}.o
 +      kallsyms_vmlinux=.tmp_vmlinux${1}
 +
-       vmlinux_link "${kallsymso_prev}" ${kallsyms_vmlinux}
++      vmlinux_link ${kallsyms_vmlinux} "${kallsymso_prev}" ${btf_vmlinux_bin_o}

Good cleanup on the "optional .o files" reordering! With your ordering
change, I think the ""s around ${kallsymso_prev} here are no longer needed
(which makes it read a bit more nicely).

quoted

 +      kallsyms ${kallsyms_vmlinux} ${kallsymso}
 +}
 +
  # Create map file with all symbols from ${1}
  # See mksymap for additional details
  mksysmap()
@@@ -228,8 -227,14 +240,15 @@@ ${MAKE} -f "${srctree}/scripts/Makefile
  info MODINFO modules.builtin.modinfo
  ${OBJCOPY} -j .modinfo -O binary vmlinux.o modules.builtin.modinfo

+ btf_vmlinux_bin_o=""
+ if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then
+       if gen_btf .tmp_vmlinux.btf .btf.vmlinux.bin.o ; then
+               btf_vmlinux_bin_o=.btf.vmlinux.bin.o
+       fi
+ fi
+
  kallsymso=""
 +kallsymso_prev=""
  kallsyms_vmlinux=""
  if [ -n "${CONFIG_KALLSYMS}" ]; then

@@@ -268,11 -285,8 +287,7 @@@
        fi
  fi

- vmlinux_link "${kallsymso}" vmlinux
-
- if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then
-       gen_btf vmlinux
- fi
 -info LD vmlinux
+ vmlinux_link vmlinux "${kallsymso}" "${btf_vmlinux_bin_o}"

And, I think, also not here for either trailing argument.

quoted

  if [ -n "${CONFIG_BUILDTIME_EXTABLE_SORT}" ]; then
        info SORTEX vmlinux

-Kees

-- 
Kees Cook