On 07/02/14 17:22, Andi Kleen wrote: > On Wed, Jul 02, 2014 at 04:21:06PM -0700, Randy Dunlap wrote: >> On 07/02/14 15:08, akpm@xxxxxxxxxxxxxxxxxxxx wrote: >>> The mm-of-the-moment snapshot 2014-07-02-15-07 has been uploaded to >>> >>> http://www.ozlabs.org/~akpm/mmotm/ >>> >>> mmotm-readme.txt says >>> >>> README for mm-of-the-moment: >>> >>> http://www.ozlabs.org/~akpm/mmotm/ >>> >>> This is a snapshot of my -mm patch queue. Uploaded at random hopefully >>> more than once a week. >> >> Hi Andi, >> >> Here is an extract from 10 randconfig builds: >> >> >> $ grep STACKPROTECTOR_STRONG config-r* >> config-r8735:CONFIG_CC_STACKPROTECTOR_STRONG=y >> config-r8736:CONFIG_CC_STACKPROTECTOR_STRONG=y >> config-r8737:# CONFIG_CC_STACKPROTECTOR_STRONG is not set >> config-r8738:# CONFIG_CC_STACKPROTECTOR_STRONG is not set >> config-r8739:CONFIG_CC_STACKPROTECTOR_STRONG=y >> config-r8740:CONFIG_CC_STACKPROTECTOR_STRONG=y >> config-r8741:CONFIG_CC_STACKPROTECTOR_STRONG=y >> config-r8742:# CONFIG_CC_STACKPROTECTOR_STRONG is not set >> config-r8743:# CONFIG_CC_STACKPROTECTOR_STRONG is not set >> config-r8744:# CONFIG_CC_STACKPROTECTOR_STRONG is not set >> >> >> but the captured output for each one says: >> >> grep STACKPROTECTOR_STRONG build*.out >> build-r8735.out:/local/lnx/MM/mmotm-2014-0702-1507/Makefile:662: Cannot use CONFIG_CC_STACKPROTECTOR_STRONG: -fstack-protector-strong not supported by compiler >> build-r8736.out:/local/lnx/MM/mmotm-2014-0702-1507/Makefile:662: Cannot use CONFIG_CC_STACKPROTECTOR_STRONG: -fstack-protector-strong not supported by compiler >> build-r8736.out:/local/lnx/MM/mmotm-2014-0702-1507/Makefile:662: Cannot use CONFIG_CC_STACKPROTECTOR_STRONG: -fstack-protector-strong not supported by compiler >> build-r8737.out:/local/lnx/MM/mmotm-2014-0702-1507/Makefile:662: Cannot use CONFIG_CC_STACKPROTECTOR_STRONG: -fstack-protector-strong not supported by compiler >> build-r8739.out:/local/lnx/MM/mmotm-2014-0702-1507/Makefile:662: Cannot use CONFIG_CC_STACKPROTECTOR_STRONG: -fstack-protector-strong not supported by compiler >> build-r8740.out:/local/lnx/MM/mmotm-2014-0702-1507/Makefile:662: Cannot use CONFIG_CC_STACKPROTECTOR_STRONG: -fstack-protector-strong not supported by compiler >> build-r8740.out:/local/lnx/MM/mmotm-2014-0702-1507/Makefile:662: Cannot use CONFIG_CC_STACKPROTECTOR_STRONG: -fstack-protector-strong not supported by compiler >> build-r8741.out:/local/lnx/MM/mmotm-2014-0702-1507/Makefile:662: Cannot use CONFIG_CC_STACKPROTECTOR_STRONG: -fstack-protector-strong not supported by compiler >> build-r8741.out:/local/lnx/MM/mmotm-2014-0702-1507/Makefile:662: Cannot use CONFIG_CC_STACKPROTECTOR_STRONG: -fstack-protector-strong not supported by compiler >> build-r8742.out:/local/lnx/MM/mmotm-2014-0702-1507/Makefile:662: Cannot use CONFIG_CC_STACKPROTECTOR_STRONG: -fstack-protector-strong not supported by compiler >> >> >> then the build goes on to produce many errors like this one: >> >> CC init/do_mounts.o >> gcc: error: unrecognized command line option '-fstack-protector-strong' >> >> >> Can you explain this, please? or even better yet, fix it. > > That's the code > > ifdef CONFIG_CC_STACKPROTECTOR_STRONG > stackp-flag := -fstack-protector-strong > ifeq ($(call cc-option, $(stackp-flag)),) > $(warning Cannot use CONFIG_CC_STACKPROTECTOR_STRONG: \ > -fstack-protector-strong not supported by compiler) > endif > else > # Force off for distro compilers that enable stack protector by default. > stackp-flag := $(call cc-option, -fno-stack-protector) > endif > endif > KBUILD_CFLAGS += $(stackp-flag) > > So -fstack-protector-strong itself is never protected by a cc-option call. ouch. > You could add it to the stack-flag line, then it would only warn. > > stackp-flag := $(call cc-option, -fstack-protector-strong) > > It's hard to tell what the original author wanted, perhaps they wanted > it to error out. It looks intentional. Clearly they didn't think of randconfig > though. > > Or get a compiler that supports stack protection? Yeah, I have plans to upgrade, just been too busy. thanks for your help. -- ~Randy -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
