Re: [PATCH net-next v3 01/16] mctp: Add MCTP base

On Thu, 12 Aug 2021 19:15:24 +0800
Jeremy Kerr [off-list ref] wrote:

Hi Geert,

Thanks for the testing!

quoted

When building an allmodconfig kernel, I got:  

[...]

I don't see this on a clean allmodconfig build, nor when building the
previous commit then the MCTP commit with something like:

  git checkout bc49d81^
  make O=obj.allmodconfig allmodconfig
  make O=obj.allmodconfig -j16
  git checkout bc49d81
  make O=obj.allmodconfig -j16

- but it seems like it might be up to the ordering of a parallel build.

quoted

From your description, it does sound like it's not regenerating flask.h;  

the kbuild rules would seem to have a classmap.h -> flask.h dependency:

  $(addprefix $(obj)/,$(selinux-y)): $(obj)/flask.h
  
  quiet_cmd_flask = GEN     $(obj)/flask.h $(obj)/av_permissions.h
        cmd_flask = scripts/selinux/genheaders/genheaders $(obj)/flask.h $(obj)/av_permissions.h
  
  targets += flask.h av_permissions.h
  $(obj)/flask.h: $(src)/include/classmap.h FORCE
  	$(call if_changed,flask)

however, classmap.h is #include-ed as part of the genheaders binary
build, rather than read at runtime; maybe $(obj)/flask.h should depend
on the genheaders binary, rather than $(src)/include/classmap.h ?

If you can reproduce, can you compare the ctimes with:

  stat scripts/selinux/genheaders/genheaders security/selinux/flask.h

I just hit the exact same issue. I build with O=../build/ and by removing
security/selinux/flask.h and av_permission.h, it built fine afterward.
Appears to be a dependency issue.

-- Steve

in your object dir?

Cheers,


Jeremy