On Tue, 2020-09-22 at 12:38 -0700, Randy Dunlap wrote: > On 9/22/20 12:19 PM, James Bottomley wrote: > > On Tue, 2020-09-22 at 11:54 -0700, Randy Dunlap wrote: > > > On 9/22/20 8:53 AM, James Bottomley wrote: > > > > I recently ran into this as an error from 0day. On x86 it's > > > > pretty > > > > much impossible to build a configuration where CONFIG_ASN1 > > > > isn't > > > > set, so you rarely notice a problem using the ASN.1 compiler > > > > because something else has selected it. However, this compiler > > > > is > > > > never built if CONFIG_ASN1 isn't set and the error you get from > > > > kbuild is particularly unhelpful: > > > > > > > > make[4]: *** No rule to make target 'security/keys/trusted- > > > > keys/tpm2key.asn1.o', needed by 'security/keys/trusted- > > > > keys/built- > > > > in.a'. > > > > make[4]: *** [scripts/Makefile.build:283: > > > > security/keys/trusted- > > > > keys/trusted_tpm2.o] Error 1 > > > > make[4]: Target '__build' not remade because of errors. > > > > > > > > This patch changes the above error to the much easier to > > > > diagnose: > > > > > > > > scripts/Makefile.build:387: *** CONFIG_ASN1 must be defined > > > > for > > > > the asn1_compiler. Stop. > > > > make[3]: *** [scripts/Makefile.build:505: > > > > security/keys/trusted- > > > > keys] Error 2 > > > > > > > > James > > > > > > > > --- > > > > > > > > James Bottomley (1): > > > > Makefile.build: Add an explicit error for missing ASN.1 > > > > compiler > > > > > > > > scripts/Makefile.build | 5 +++++ > > > > 1 file changed, 5 insertions(+) > > > > > > Is there a missing > > > select ASN1 > > > somewhere? > > > > You mean in the build used to produce the errors above? Yes, so > > the > > patch is to make the problem more explicit. > > I appreciate that the message can be improved, but it seems possible > that some Kconfig could also be improved. I don't really see how. To find the problem you have to identify a conditional build in the Makefile that requires the asn1 compiler but for which the config option doesn't have a select ASN1. We don't currently preserve the "what selected this symbol" information in kconfig, which is what we'd need. James
