Re: [PATCH v8 00/21] Compile-time stack validation

Re: [PATCH v8 00/21] Compile-time stack validation

[Chris J Arges]

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

Re: [PATCH v8 00/21] Compile-time stack validation

[Josh Poimboeuf]

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

Re: [PATCH v8 00/21] Compile-time stack validation

[Chris J Arges]

<snip>
> 
> 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
>  
> 

Josh,

I still get build failures and I've pared it down to x86_64 defconfig plus:
CONFIG_MODVERSIONS=y
CONFIG_STACK_VALIDATION=y

And it seems like some modules may get the .tmp_foo.o treatment while
others end up foo.o so something like the following will not work:

cmd_stackvalidate = $(if $(patsubst n%,, \
        $(STACKVALIDATE_$(basetarget).o)$(STACKVALIDATE)y), \
        $(__stackvalidate) $(nofp) "$(@D)/.tmp_$(@F)";)

In addition, I'm not sure if skipping modules like STACKVALIDATE_foo.o=n
will still function properly for modversioned modules.

I'll try to look at this more tomorrow,
--chris j arges

Re: [PATCH v8 00/21] Compile-time stack validation

[Josh Poimboeuf]

On Wed, Aug 12, 2015 at 04:24:49PM -0500, Chris J Arges wrote:
> <snip>
> > 
> > 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
> >  
> > 
> 
> Josh,
> 
> I still get build failures and I've pared it down to x86_64 defconfig plus:
> CONFIG_MODVERSIONS=y
> CONFIG_STACK_VALIDATION=y

Are you still seeing the same error as before?  I think the errors you
saw were caused by stackvalidate choking on scripts/mod/empty.o.  But I
don't see how that's still possible with the above patch since I set
STACKVALIDATE to 'n' in scripts/mod/Makefile which should tell it to
skip the directory.

> And it seems like some modules may get the .tmp_foo.o treatment while
> others end up foo.o so something like the following will not work:
> 
> cmd_stackvalidate = $(if $(patsubst n%,, \
>         $(STACKVALIDATE_$(basetarget).o)$(STACKVALIDATE)y), \
>         $(__stackvalidate) $(nofp) "$(@D)/.tmp_$(@F)";)
> 
> In addition, I'm not sure if skipping modules like STACKVALIDATE_foo.o=n
> will still function properly for modversioned modules.

I'm not sure that's really a problem, since I don't think we'll need to
skip validation of any module code.  It's only used for skipping code
which runs outside of the kernel's normal operation (e.g., boot, vdso,
kexec).

-- 
Josh

Re: [PATCH v8 00/21] Compile-time stack validation

[Josh Poimboeuf]

On Wed, Aug 12, 2015 at 04:24:49PM -0500, Chris J Arges wrote:
> I still get build failures and I've pared it down to x86_64 defconfig plus:
> CONFIG_MODVERSIONS=y
> CONFIG_STACK_VALIDATION=y
> 
> And it seems like some modules may get the .tmp_foo.o treatment while
> others end up foo.o so something like the following will not work:
> 
> cmd_stackvalidate = $(if $(patsubst n%,, \
>         $(STACKVALIDATE_$(basetarget).o)$(STACKVALIDATE)y), \
>         $(__stackvalidate) $(nofp) "$(@D)/.tmp_$(@F)";)

Does this fix it?

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index ec96c51..0181915 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -263,8 +263,8 @@ endif # CONFIG_STACK_VALIDATION
 define rule_cc_o_c
 	$(call echo-cmd,checksrc) $(cmd_checksrc)			  \
 	$(call echo-cmd,cc_o_c) $(cmd_cc_o_c);				  \
-	$(cmd_stackvalidate)						  \
 	$(cmd_modversions)						  \
+	$(cmd_stackvalidate)						  \
 	$(call echo-cmd,record_mcount)					  \
 	$(cmd_record_mcount)						  \
 	scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,cc_o_c)' >    \

Re: [PATCH v8 00/21] Compile-time stack validation

[Chris J Arges]

On Thu, Aug 13, 2015 at 06:22:20AM -0500, Josh Poimboeuf wrote:
> On Wed, Aug 12, 2015 at 04:24:49PM -0500, Chris J Arges wrote:
> > I still get build failures and I've pared it down to x86_64 defconfig plus:
> > CONFIG_MODVERSIONS=y
> > CONFIG_STACK_VALIDATION=y
> > 
> > And it seems like some modules may get the .tmp_foo.o treatment while
> > others end up foo.o so something like the following will not work:
> > 
> > cmd_stackvalidate = $(if $(patsubst n%,, \
> >         $(STACKVALIDATE_$(basetarget).o)$(STACKVALIDATE)y), \
> >         $(__stackvalidate) $(nofp) "$(@D)/.tmp_$(@F)";)
> 
> Does this fix it?
> 
> diff --git a/scripts/Makefile.build b/scripts/Makefile.build
> index ec96c51..0181915 100644
> --- a/scripts/Makefile.build
> +++ b/scripts/Makefile.build
> @@ -263,8 +263,8 @@ endif # CONFIG_STACK_VALIDATION
>  define rule_cc_o_c
>  	$(call echo-cmd,checksrc) $(cmd_checksrc)			  \
>  	$(call echo-cmd,cc_o_c) $(cmd_cc_o_c);				  \
> -	$(cmd_stackvalidate)						  \
>  	$(cmd_modversions)						  \
> +	$(cmd_stackvalidate)						  \
>  	$(call echo-cmd,record_mcount)					  \
>  	$(cmd_record_mcount)						  \
>  	scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,cc_o_c)' >    \
>

Josh,

Yes, this fixes my build. For completeness this is my current diff:

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index a1270d3..0181915 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
@@ -251,17 +251,20 @@ 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
 
 define rule_cc_o_c
 	$(call echo-cmd,checksrc) $(cmd_checksrc)			  \
 	$(call echo-cmd,cc_o_c) $(cmd_cc_o_c);				  \
-	$(cmd_stackvalidate)						  \
 	$(cmd_modversions)						  \
+	$(cmd_stackvalidate)						  \
 	$(call echo-cmd,record_mcount)					  \
 	$(cmd_record_mcount)						  \
 	scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,cc_o_c)' >    \
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

Thanks,
--chris
 

Re: [PATCH v8 00/21] Compile-time stack validation

[Josh Poimboeuf]

On Thu, Aug 13, 2015 at 09:42:25AM -0500, Chris J Arges wrote:
> On Thu, Aug 13, 2015 at 06:22:20AM -0500, Josh Poimboeuf wrote:
> > On Wed, Aug 12, 2015 at 04:24:49PM -0500, Chris J Arges wrote:
> > > I still get build failures and I've pared it down to x86_64 defconfig plus:
> > > CONFIG_MODVERSIONS=y
> > > CONFIG_STACK_VALIDATION=y
> > > 
> > > And it seems like some modules may get the .tmp_foo.o treatment while
> > > others end up foo.o so something like the following will not work:
> > > 
> > > cmd_stackvalidate = $(if $(patsubst n%,, \
> > >         $(STACKVALIDATE_$(basetarget).o)$(STACKVALIDATE)y), \
> > >         $(__stackvalidate) $(nofp) "$(@D)/.tmp_$(@F)";)
> > 
> > Does this fix it?
> > 
> > diff --git a/scripts/Makefile.build b/scripts/Makefile.build
> > index ec96c51..0181915 100644
> > --- a/scripts/Makefile.build
> > +++ b/scripts/Makefile.build
> > @@ -263,8 +263,8 @@ endif # CONFIG_STACK_VALIDATION
> >  define rule_cc_o_c
> >  	$(call echo-cmd,checksrc) $(cmd_checksrc)			  \
> >  	$(call echo-cmd,cc_o_c) $(cmd_cc_o_c);				  \
> > -	$(cmd_stackvalidate)						  \
> >  	$(cmd_modversions)						  \
> > +	$(cmd_stackvalidate)						  \
> >  	$(call echo-cmd,record_mcount)					  \
> >  	$(cmd_record_mcount)						  \
> >  	scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,cc_o_c)' >    \
> >
> 
> Josh,
> 
> Yes, this fixes my build. For completeness this is my current diff:

Great!  I'll roll both patches into v10.

-- 
Josh

Re: [PATCH v8 00/21] Compile-time stack validation

[Josh Poimboeuf]

On Thu, Aug 06, 2015 at 12:23:32PM -0500, Josh Poimboeuf wrote:
> On Thu, Aug 06, 2015 at 10:07:50AM +0200, Ingo Molnar wrote:
> > 
> > * Josh Poimboeuf <jpoimboe@redhat.com> wrote:
> > 
> > > This is v8 of the compile-time stack validation patch set, based on the
> > > tip/master branch.
> > > 
> > > The frame pointer macros are still called FRAME and ENDFRAME because I
> > > don't think we converged on anything else yet.  Otherwise I tried to
> > > address all the other review comments from v7.
> > 
> > So I think:
> > 
> > 	FRAME_START
> > 	FRAME_END
> 
> (One last tweak to the bikeshed)
> 
> The antonym of END is BEGIN.  So how about:
> 
>   FRAME_BEGIN
>   FRAME_END

Ok, so thesaurus.com reminds me that words can have more than one
antonym, and that START and BEGIN are both antonyms of END.

Personally, when I START something I usually FINISH it or even STOP it.

So I'll stop the bikeshedding I started and go with BEGIN/END.

-- 
Josh

Re: [PATCH v8 00/21] Compile-time stack validation

[Josh Poimboeuf]

On Thu, Aug 06, 2015 at 10:07:50AM +0200, Ingo Molnar wrote:
> 
> * Josh Poimboeuf <jpoimboe@redhat.com> wrote:
> 
> > This is v8 of the compile-time stack validation patch set, based on the
> > tip/master branch.
> > 
> > The frame pointer macros are still called FRAME and ENDFRAME because I
> > don't think we converged on anything else yet.  Otherwise I tried to
> > address all the other review comments from v7.
> 
> So I think:
> 
> 	FRAME_START
> 	FRAME_END

(One last tweak to the bikeshed)

The antonym of END is BEGIN.  So how about:

  FRAME_BEGIN
  FRAME_END


-- 
Josh

Re: [PATCH v8 00/21] Compile-time stack validation

[Josh Poimboeuf]

On Thu, Aug 06, 2015 at 10:07:50AM +0200, Ingo Molnar wrote:
> 
> * Josh Poimboeuf <jpoimboe@redhat.com> wrote:
> 
> > This is v8 of the compile-time stack validation patch set, based on the
> > tip/master branch.
> > 
> > The frame pointer macros are still called FRAME and ENDFRAME because I
> > don't think we converged on anything else yet.  Otherwise I tried to
> > address all the other review comments from v7.
> 
> So I think:
> 
> 	FRAME_START
> 	FRAME_END
> 
> would be OK.

Thanks, that sounds good to me.

> They could be added as new aliases, keeping the old ones as well, while in the new 
> patches you should use this new form.

Turns out nobody uses the existing FRAME/ENDFRAME macros, so I'll just
rename them.

-- 
Josh

Re: [PATCH v8 00/21] Compile-time stack validation

[Ingo Molnar]

* Josh Poimboeuf <jpoimboe@redhat.com> wrote:

> This is v8 of the compile-time stack validation patch set, based on the
> tip/master branch.
> 
> The frame pointer macros are still called FRAME and ENDFRAME because I
> don't think we converged on anything else yet.  Otherwise I tried to
> address all the other review comments from v7.

So I think:

	FRAME_START
	FRAME_END

would be OK.

They could be added as new aliases, keeping the old ones as well, while in the new 
patches you should use this new form.

Thanks,

	Ingo

[PATCH v8 00/21] Compile-time stack validation

[Josh Poimboeuf]

This is v8 of the compile-time stack validation patch set, based on the
tip/master branch.

The frame pointer macros are still called FRAME and ENDFRAME because I
don't think we converged on anything else yet.  Otherwise I tried to
address all the other review comments from v7.

v7 can be found here:

  https://lkml.kernel.org/r/cover.1436893563.git.jpoimboe@redhat.com

For more information about the motivation behind this patch set, and
more details about what it does, please see the changelog in patch 3.

Patches 1-5 are the stackvalidate tool and some related macros.

Patches 6-21 are some proposed fixes for several of the warnings
reported by stackvalidate.  They've been compile-tested and boot tested
in a VM, but I haven't attempted any meaningful testing for many of
them.

v8:
- add proposed fixes for warnings
- fix all memory leaks
- process ignores earlier and add more ignore checks
- always assume POPCNT alternative is enabled
- drop hweight inline asm fix
- drop __schedule() ignore patch
- change .Ltemp_\@ to .Lstackvalidate_ignore_\@ in asm macro
- fix CONFIG_* checks in asm macros
- add C versions of ignore macros and frame macros
- change ";" to "\n" in C macros
- add ifdef CONFIG_STACK_VALIDATION checks in C ignore macros
- use numbered label in C ignore macro
- add missing break in switch case statement in arch-x86.c

v7:
- sibling call support
- document proposed solution for inline asm() frame pointer issues
- say "kernel entry/exit" instead of "context switch"
- clarify the checking of switch statement jump tables
- discard __stackvalidate_ignore_* sections in linker script
- use .Ltemp_\@ to get a unique label instead of static 3-digit number
- change STACKVALIDATE_IGNORE_FUNC variable to a static
- move STACKVALIDATE_IGNORE_INSN to arch-specific .h file

v6:
- rename asmvalidate -> stackvalidate (again)
- gcc-generated object file support
- recursive branch state analysis
- external jump support
- fixup/exception table support
- jump label support
- switch statement jump table support
- added documentation
- detection of "noreturn" dead end functions
- added a Kbuild mechanism for skipping files and dirs
- moved frame pointer macros to arch/x86/include/asm/frame.h
- moved ignore macros to include/linux/stackvalidate.h

v5:
- stackvalidate -> asmvalidate
- frame pointers only required for non-leaf functions
- check for the use of the FP_SAVE/RESTORE macros instead of manually
  analyzing code to detect frame pointer usage
- additional checks to ensure each function doesn't leave its boundaries
- make the macros simpler and more flexible
- support for analyzing ALTERNATIVE macros
- simplified the arch interfaces in scripts/asmvalidate/arch.h
- fixed some asmvalidate warnings
- rebased onto latest tip asm cleanups
- many more small changes

v4:
- Changed the default to CONFIG_STACK_VALIDATION=n, until all the asm
  code can get cleaned up.
- Fixed a stackvalidate error path exit code issue found by Michal
  Marek.

v3:
- Added a patch to make the push/pop CFI macros arch-independent, as
  suggested by H. Peter Anvin

v2:
- Fixed memory leaks reported by Petr Mladek

Josh Poimboeuf (21):
  x86/asm: Frame pointer macro cleanup
  x86/asm: Add C versions of FRAME and ENDFRAME macros
  x86/stackvalidate: Compile-time stack validation
  x86/stackvalidate: Add file and directory ignores
  x86/stackvalidate: Add ignore macros
  x86/xen: Add stack frame dependency to hypercall inline asm calls
  x86/paravirt: Add stack frame dependency to PVOP inline asm calls
  x86/paravirt: Fix frame pointer usage in PV_CALLEE_SAVE_REGS_THUNK
  x86/paravirt: Align paravirt thunk functions at 16-byte boundaries
  x86/amd: Set ELF function type for vide()
  x86/reboot: Add ljmp instructions to stackvalidate whitelist
  x86/xen: Add xen_cpuid() and xen_setup_gdt() to stackvalidate
    whitelists
  x86/asm/crypto: Fix frame pointer usage in aesni-intel_asm.S
  x86/asm/crypto: Move .Lbswap_mask data to .rodata section
  x86/asm/crypto: Move jump_table to .rodata section
  x86/asm/crypto: Fix frame pointer usage in clmul_ghash_mul/update()
  x86/asm/entry: Fix frame pointer usage in thunk functions
  x86/asm/acpi: Fix frame pointer usage in do_suspend_lowlevel()
  x86/asm: Fix frame pointer usage in rwsem functions
  x86/asm/efi: Fix frame pointer usage in efi_call()
  x86/asm/power: Fix frame pointer usage in hibernate_asm_64.S

 Documentation/stack-validation.txt        | 193 ++++++
 MAINTAINERS                               |   8 +
 arch/Kconfig                              |   6 +
 arch/x86/Kconfig                          |   1 +
 arch/x86/Makefile                         |   6 +-
 arch/x86/boot/Makefile                    |   3 +-
 arch/x86/boot/compressed/Makefile         |   3 +-
 arch/x86/crypto/aesni-intel_asm.S         |  21 +
 arch/x86/crypto/crc32c-pcl-intel-asm_64.S |   8 +-
 arch/x86/crypto/ghash-clmulni-intel_asm.S |   5 +
 arch/x86/entry/thunk_64.S                 |   4 +
 arch/x86/entry/vdso/Makefile              |   5 +-
 arch/x86/include/asm/frame.h              |  51 +-
 arch/x86/include/asm/paravirt.h           |  10 +-
 arch/x86/include/asm/paravirt_types.h     |  18 +-
 arch/x86/include/asm/stackvalidate.h      |  45 ++
 arch/x86/include/asm/xen/hypercall.h      |   5 +-
 arch/x86/kernel/acpi/wakeup_64.S          |   3 +
 arch/x86/kernel/cpu/amd.c                 |   5 +-
 arch/x86/kernel/reboot.c                  |   7 +-
 arch/x86/kernel/vmlinux.lds.S             |   5 +-
 arch/x86/lib/rwsem.S                      |  11 +-
 arch/x86/platform/efi/efi_stub_64.S       |   3 +
 arch/x86/power/hibernate_asm_64.S         |   7 +
 arch/x86/purgatory/Makefile               |   2 +
 arch/x86/realmode/Makefile                |   4 +-
 arch/x86/realmode/rm/Makefile             |   3 +-
 arch/x86/xen/enlighten.c                  |   4 +-
 drivers/firmware/efi/libstub/Makefile     |   1 +
 include/linux/stackvalidate.h             |  28 +
 lib/Kconfig.debug                         |  11 +
 scripts/Makefile                          |   1 +
 scripts/Makefile.build                    |  34 +-
 scripts/stackvalidate/Makefile            |  24 +
 scripts/stackvalidate/arch-x86.c          | 160 +++++
 scripts/stackvalidate/arch.h              |  44 ++
 scripts/stackvalidate/elf.c               | 427 ++++++++++++++
 scripts/stackvalidate/elf.h               |  92 +++
 scripts/stackvalidate/list.h              | 217 +++++++
 scripts/stackvalidate/special.c           | 197 +++++++
 scripts/stackvalidate/special.h           |  41 ++
 scripts/stackvalidate/stackvalidate.c     | 949 ++++++++++++++++++++++++++++++
 42 files changed, 2624 insertions(+), 48 deletions(-)
 create mode 100644 Documentation/stack-validation.txt
 create mode 100644 arch/x86/include/asm/stackvalidate.h
 create mode 100644 include/linux/stackvalidate.h
 create mode 100644 scripts/stackvalidate/Makefile
 create mode 100644 scripts/stackvalidate/arch-x86.c
 create mode 100644 scripts/stackvalidate/arch.h
 create mode 100644 scripts/stackvalidate/elf.c
 create mode 100644 scripts/stackvalidate/elf.h
 create mode 100644 scripts/stackvalidate/list.h
 create mode 100644 scripts/stackvalidate/special.c
 create mode 100644 scripts/stackvalidate/special.h
 create mode 100644 scripts/stackvalidate/stackvalidate.c

-- 
2.1.0