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SubjectRe: [PATCH v8 00/21] Compile-time stack validation
On Tue, Aug 11, 2015 at 04:31:07PM -0500, Chris J Arges wrote:
> Josh,
>
> I've applied and tried to build your patchset against the latest
> mainline kernel with the following config:
> http://paste.ubuntu.com/12058017/
>
> I can build if I disable CONFIG_STACK_VALIDATION, then re-enable it
> after all objects are already built, so this seems like it should be
> resolvable in Makefiles. Any suggestions for debugging this?
>
> Building from clean I get the following:
> ~/linux$ make
> HOSTCC scripts/basic/fixdep
> HOSTCC scripts/basic/bin2c
> GEN arch/x86/lib/inat-tables.c
> HOSTCC arch/x86/tools/relocs_32.o
> HOSTCC arch/x86/tools/relocs_64.o
> HOSTCC arch/x86/tools/relocs_common.o
> HOSTLD arch/x86/tools/relocs
> CHK include/config/kernel.release
> CHK include/generated/uapi/linux/version.h
> CHK include/generated/utsrelease.h
> CC arch/x86/purgatory/purgatory.o
> AS arch/x86/purgatory/stack.o
> AS arch/x86/purgatory/setup-x86_64.o
> CC arch/x86/purgatory/sha256.o
> AS arch/x86/purgatory/entry64.o
> CC arch/x86/purgatory/string.o
> LD arch/x86/purgatory/purgatory.ro
> BIN2C arch/x86/purgatory/kexec-purgatory.c
> CC kernel/bounds.s
> CHK include/generated/bounds.h
> CHK include/generated/timeconst.h
> CC arch/x86/kernel/asm-offsets.s
> CHK include/generated/asm-offsets.h
> CALL scripts/checksyscalls.sh
> HOSTCC scripts/genksyms/genksyms.o
> HOSTCC scripts/genksyms/parse.tab.o
> HOSTCC scripts/genksyms/lex.lex.o
> HOSTLD scripts/genksyms/genksyms
> CC scripts/mod/empty.o
> scripts/mod/empty.o
> open: No such file or directory
> error reading elf file scripts/mod/empty.o
> scripts/Makefile.build:284: recipe for target 'scripts/mod/empty.o' failed
> make[2]: *** [scripts/mod/empty.o] Error 1
> scripts/Makefile.build:429: recipe for target 'scripts/mod' failed
> make[1]: *** [scripts/mod] Error 2
> Makefile:545: recipe for target 'scripts' failed
> make: *** [scripts] Error 2

Thanks for trying it out. I couldn't figure out how to recreate this
exact error, but I played around with "make mrproper" and saw some
probably related errors. Does this fix it?

---8<---

Subject: [PATCH] stackvalidate: fix circular build dependencies

After "make mrproper" with CONFIG_STACK_VALIDATION enabled, I get the
following errors:

make[2]: *** No rule to make target 'arch/x86/purgatory/purgatory.o', needed by 'arch/x86/purgatory/purgatory.ro'. Stop.
make[3]: *** No rule to make target 'scripts/mod/empty.o', needed by 'scripts/mod/elfconfig.h'. Stop.

These are caused by circular dependencies. The %.o pattern rules in
scripts/Makefile.build have the stackvalidate binary listed as a
dependency. But stackvalidate gets built *after* archprepare and
scripts/mod, both of which build objects using the %.o pattern rules.

The STACKVALIDATE and STACKVALIDATE_foo.o variables are already used to
determine whether to validate a given object. Also use them to
determine whether to create the pattern rule dependency.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
scripts/Makefile.build | 7 +++++--
scripts/mod/Makefile | 2 ++
2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index a1270d3..ec96c51 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -243,7 +243,7 @@ endif

ifdef CONFIG_STACK_VALIDATION

-stackvalidate = $(objtree)/scripts/stackvalidate/stackvalidate
+__stackvalidate = $(objtree)/scripts/stackvalidate/stackvalidate

ifndef CONFIG_FRAME_POINTER
nofp = --no-frame-pointer
@@ -251,9 +251,12 @@ endif

# Set STACKVALIDATE_foo.o=n to skip stack validation for a file.
# Set STACKVALIDATE=n to skip stack validation for a directory.
+stackvalidate = $(if $(patsubst n%,, \
+ $(STACKVALIDATE_$(basetarget).o)$(STACKVALIDATE)y), \
+ $(__stackvalidate))
cmd_stackvalidate = $(if $(patsubst n%,, \
$(STACKVALIDATE_$(basetarget).o)$(STACKVALIDATE)y), \
- $(stackvalidate) $(nofp) "$(@)";)
+ $(__stackvalidate) $(nofp) "$(@)";)

endif # CONFIG_STACK_VALIDATION

diff --git a/scripts/mod/Makefile b/scripts/mod/Makefile
index c11212f..374c413 100644
--- a/scripts/mod/Makefile
+++ b/scripts/mod/Makefile
@@ -1,3 +1,5 @@
+STACKVALIDATE := n
+
hostprogs-y := modpost mk_elfconfig
always := $(hostprogs-y) empty.o

--
2.4.3


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