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* FAILED: patch "[PATCH] x86/purgatory: Use CFLAGS_REMOVE rather than reset" failed to apply to 4.9-stable tree
@ 2019-08-13 18:40 gregkh
  2019-08-13 20:29 ` Nick Desaulniers
  0 siblings, 1 reply; 3+ messages in thread
From: gregkh @ 2019-08-13 18:40 UTC (permalink / raw)
  To: ndesaulniers, peterz, tglx, vaibhavrustagi; +Cc: stable


The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From b059f801a937d164e03b33c1848bb3dca67c0b04 Mon Sep 17 00:00:00 2001
From: Nick Desaulniers <ndesaulniers@google.com>
Date: Wed, 7 Aug 2019 15:15:33 -0700
Subject: [PATCH] x86/purgatory: Use CFLAGS_REMOVE rather than reset
 KBUILD_CFLAGS

KBUILD_CFLAGS is very carefully built up in the top level Makefile,
particularly when cross compiling or using different build tools.
Resetting KBUILD_CFLAGS via := assignment is an antipattern.

The comment above the reset mentions that -pg is problematic.  Other
Makefiles use `CFLAGS_REMOVE_file.o = $(CC_FLAGS_FTRACE)` when
CONFIG_FUNCTION_TRACER is set. Prefer that pattern to wiping out all of
the important KBUILD_CFLAGS then manually having to re-add them. Seems
also that __stack_chk_fail references are generated when using
CONFIG_STACKPROTECTOR or CONFIG_STACKPROTECTOR_STRONG.

Fixes: 8fc5b4d4121c ("purgatory: core purgatory functionality")
Reported-by: Vaibhav Rustagi <vaibhavrustagi@google.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Vaibhav Rustagi <vaibhavrustagi@google.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20190807221539.94583-2-ndesaulniers@google.com

diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
index 91ef244026d2..8901a1f89cf5 100644
--- a/arch/x86/purgatory/Makefile
+++ b/arch/x86/purgatory/Makefile
@@ -20,11 +20,34 @@ KCOV_INSTRUMENT := n
 
 # Default KBUILD_CFLAGS can have -pg option set when FTRACE is enabled. That
 # in turn leaves some undefined symbols like __fentry__ in purgatory and not
-# sure how to relocate those. Like kexec-tools, use custom flags.
-
-KBUILD_CFLAGS := -fno-strict-aliasing -Wall -Wstrict-prototypes -fno-zero-initialized-in-bss -fno-builtin -ffreestanding -c -Os -mcmodel=large
-KBUILD_CFLAGS += -m$(BITS)
-KBUILD_CFLAGS += $(call cc-option,-fno-PIE)
+# sure how to relocate those.
+ifdef CONFIG_FUNCTION_TRACER
+CFLAGS_REMOVE_sha256.o		+= $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_purgatory.o	+= $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_string.o		+= $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_kexec-purgatory.o	+= $(CC_FLAGS_FTRACE)
+endif
+
+ifdef CONFIG_STACKPROTECTOR
+CFLAGS_REMOVE_sha256.o		+= -fstack-protector
+CFLAGS_REMOVE_purgatory.o	+= -fstack-protector
+CFLAGS_REMOVE_string.o		+= -fstack-protector
+CFLAGS_REMOVE_kexec-purgatory.o	+= -fstack-protector
+endif
+
+ifdef CONFIG_STACKPROTECTOR_STRONG
+CFLAGS_REMOVE_sha256.o		+= -fstack-protector-strong
+CFLAGS_REMOVE_purgatory.o	+= -fstack-protector-strong
+CFLAGS_REMOVE_string.o		+= -fstack-protector-strong
+CFLAGS_REMOVE_kexec-purgatory.o	+= -fstack-protector-strong
+endif
+
+ifdef CONFIG_RETPOLINE
+CFLAGS_REMOVE_sha256.o		+= $(RETPOLINE_CFLAGS)
+CFLAGS_REMOVE_purgatory.o	+= $(RETPOLINE_CFLAGS)
+CFLAGS_REMOVE_string.o		+= $(RETPOLINE_CFLAGS)
+CFLAGS_REMOVE_kexec-purgatory.o	+= $(RETPOLINE_CFLAGS)
+endif
 
 $(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
 		$(call if_changed,ld)


^ permalink raw reply related	[flat|nested] 3+ messages in thread
* Re: FAILED: patch "[PATCH] x86/purgatory: Use CFLAGS_REMOVE rather than reset" failed to apply to 4.9-stable tree
  2019-08-13 18:40 FAILED: patch "[PATCH] x86/purgatory: Use CFLAGS_REMOVE rather than reset" failed to apply to 4.9-stable tree gregkh
@ 2019-08-13 20:29 ` Nick Desaulniers
  2019-08-13 20:37   ` Vaibhav Rustagi
  0 siblings, 1 reply; 3+ messages in thread
From: Nick Desaulniers @ 2019-08-13 20:29 UTC (permalink / raw)
  To: Vaibhav Rustagi; +Cc: Peter Zijlstra, Thomas Gleixner, # 3.4.x, Greg KH

Hi Vaibhav,
What LTS kernel are you basing your distro off of?  IIRC, 4.19, or was
it further back?

On Tue, Aug 13, 2019 at 11:40 AM <gregkh@linuxfoundation.org> wrote:
>
>
> The patch below does not apply to the 4.9-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.
>
> thanks,
>
> greg k-h
>
> ------------------ original commit in Linus's tree ------------------
>
> From b059f801a937d164e03b33c1848bb3dca67c0b04 Mon Sep 17 00:00:00 2001
> From: Nick Desaulniers <ndesaulniers@google.com>
> Date: Wed, 7 Aug 2019 15:15:33 -0700
> Subject: [PATCH] x86/purgatory: Use CFLAGS_REMOVE rather than reset
>  KBUILD_CFLAGS
>
> KBUILD_CFLAGS is very carefully built up in the top level Makefile,
> particularly when cross compiling or using different build tools.
> Resetting KBUILD_CFLAGS via := assignment is an antipattern.
>
> The comment above the reset mentions that -pg is problematic.  Other
> Makefiles use `CFLAGS_REMOVE_file.o = $(CC_FLAGS_FTRACE)` when
> CONFIG_FUNCTION_TRACER is set. Prefer that pattern to wiping out all of
> the important KBUILD_CFLAGS then manually having to re-add them. Seems
> also that __stack_chk_fail references are generated when using
> CONFIG_STACKPROTECTOR or CONFIG_STACKPROTECTOR_STRONG.
>
> Fixes: 8fc5b4d4121c ("purgatory: core purgatory functionality")
> Reported-by: Vaibhav Rustagi <vaibhavrustagi@google.com>
> Suggested-by: Peter Zijlstra <peterz@infradead.org>
> Suggested-by: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Tested-by: Vaibhav Rustagi <vaibhavrustagi@google.com>
> Cc: stable@vger.kernel.org
> Link: https://lkml.kernel.org/r/20190807221539.94583-2-ndesaulniers@google.com
>
> diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
> index 91ef244026d2..8901a1f89cf5 100644
> --- a/arch/x86/purgatory/Makefile
> +++ b/arch/x86/purgatory/Makefile
> @@ -20,11 +20,34 @@ KCOV_INSTRUMENT := n
>
>  # Default KBUILD_CFLAGS can have -pg option set when FTRACE is enabled. That
>  # in turn leaves some undefined symbols like __fentry__ in purgatory and not
> -# sure how to relocate those. Like kexec-tools, use custom flags.
> -
> -KBUILD_CFLAGS := -fno-strict-aliasing -Wall -Wstrict-prototypes -fno-zero-initialized-in-bss -fno-builtin -ffreestanding -c -Os -mcmodel=large
> -KBUILD_CFLAGS += -m$(BITS)
> -KBUILD_CFLAGS += $(call cc-option,-fno-PIE)
> +# sure how to relocate those.
> +ifdef CONFIG_FUNCTION_TRACER
> +CFLAGS_REMOVE_sha256.o         += $(CC_FLAGS_FTRACE)
> +CFLAGS_REMOVE_purgatory.o      += $(CC_FLAGS_FTRACE)
> +CFLAGS_REMOVE_string.o         += $(CC_FLAGS_FTRACE)
> +CFLAGS_REMOVE_kexec-purgatory.o        += $(CC_FLAGS_FTRACE)
> +endif
> +
> +ifdef CONFIG_STACKPROTECTOR
> +CFLAGS_REMOVE_sha256.o         += -fstack-protector
> +CFLAGS_REMOVE_purgatory.o      += -fstack-protector
> +CFLAGS_REMOVE_string.o         += -fstack-protector
> +CFLAGS_REMOVE_kexec-purgatory.o        += -fstack-protector
> +endif
> +
> +ifdef CONFIG_STACKPROTECTOR_STRONG
> +CFLAGS_REMOVE_sha256.o         += -fstack-protector-strong
> +CFLAGS_REMOVE_purgatory.o      += -fstack-protector-strong
> +CFLAGS_REMOVE_string.o         += -fstack-protector-strong
> +CFLAGS_REMOVE_kexec-purgatory.o        += -fstack-protector-strong
> +endif
> +
> +ifdef CONFIG_RETPOLINE
> +CFLAGS_REMOVE_sha256.o         += $(RETPOLINE_CFLAGS)
> +CFLAGS_REMOVE_purgatory.o      += $(RETPOLINE_CFLAGS)
> +CFLAGS_REMOVE_string.o         += $(RETPOLINE_CFLAGS)
> +CFLAGS_REMOVE_kexec-purgatory.o        += $(RETPOLINE_CFLAGS)
> +endif
>
>  $(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
>                 $(call if_changed,ld)
>


-- 
Thanks,
~Nick Desaulniers

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: FAILED: patch "[PATCH] x86/purgatory: Use CFLAGS_REMOVE rather than reset" failed to apply to 4.9-stable tree
  2019-08-13 20:29 ` Nick Desaulniers
@ 2019-08-13 20:37   ` Vaibhav Rustagi
  0 siblings, 0 replies; 3+ messages in thread
From: Vaibhav Rustagi @ 2019-08-13 20:37 UTC (permalink / raw)
  To: Nick Desaulniers; +Cc: Peter Zijlstra, Thomas Gleixner, # 3.4.x, Greg KH

On Tue, Aug 13, 2019 at 1:30 PM Nick Desaulniers
<ndesaulniers@google.com> wrote:
>
> Hi Vaibhav,
> What LTS kernel are you basing your distro off of?  IIRC, 4.19, or was
> it further back?
>
We are using 4.19.
> On Tue, Aug 13, 2019 at 11:40 AM <gregkh@linuxfoundation.org> wrote:
> >
> >
> > The patch below does not apply to the 4.9-stable tree.
> > If someone wants it applied there, or to any other stable or longterm
> > tree, then please email the backport, including the original git commit
> > id to <stable@vger.kernel.org>.
> >
> > thanks,
> >
> > greg k-h
> >
> > ------------------ original commit in Linus's tree ------------------
> >
> > From b059f801a937d164e03b33c1848bb3dca67c0b04 Mon Sep 17 00:00:00 2001
> > From: Nick Desaulniers <ndesaulniers@google.com>
> > Date: Wed, 7 Aug 2019 15:15:33 -0700
> > Subject: [PATCH] x86/purgatory: Use CFLAGS_REMOVE rather than reset
> >  KBUILD_CFLAGS
> >
> > KBUILD_CFLAGS is very carefully built up in the top level Makefile,
> > particularly when cross compiling or using different build tools.
> > Resetting KBUILD_CFLAGS via := assignment is an antipattern.
> >
> > The comment above the reset mentions that -pg is problematic.  Other
> > Makefiles use `CFLAGS_REMOVE_file.o = $(CC_FLAGS_FTRACE)` when
> > CONFIG_FUNCTION_TRACER is set. Prefer that pattern to wiping out all of
> > the important KBUILD_CFLAGS then manually having to re-add them. Seems
> > also that __stack_chk_fail references are generated when using
> > CONFIG_STACKPROTECTOR or CONFIG_STACKPROTECTOR_STRONG.
> >
> > Fixes: 8fc5b4d4121c ("purgatory: core purgatory functionality")
> > Reported-by: Vaibhav Rustagi <vaibhavrustagi@google.com>
> > Suggested-by: Peter Zijlstra <peterz@infradead.org>
> > Suggested-by: Thomas Gleixner <tglx@linutronix.de>
> > Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
> > Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> > Tested-by: Vaibhav Rustagi <vaibhavrustagi@google.com>
> > Cc: stable@vger.kernel.org
> > Link: https://lkml.kernel.org/r/20190807221539.94583-2-ndesaulniers@google.com
> >
> > diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
> > index 91ef244026d2..8901a1f89cf5 100644
> > --- a/arch/x86/purgatory/Makefile
> > +++ b/arch/x86/purgatory/Makefile
> > @@ -20,11 +20,34 @@ KCOV_INSTRUMENT := n
> >
> >  # Default KBUILD_CFLAGS can have -pg option set when FTRACE is enabled. That
> >  # in turn leaves some undefined symbols like __fentry__ in purgatory and not
> > -# sure how to relocate those. Like kexec-tools, use custom flags.
> > -
> > -KBUILD_CFLAGS := -fno-strict-aliasing -Wall -Wstrict-prototypes -fno-zero-initialized-in-bss -fno-builtin -ffreestanding -c -Os -mcmodel=large
> > -KBUILD_CFLAGS += -m$(BITS)
> > -KBUILD_CFLAGS += $(call cc-option,-fno-PIE)
> > +# sure how to relocate those.
> > +ifdef CONFIG_FUNCTION_TRACER
> > +CFLAGS_REMOVE_sha256.o         += $(CC_FLAGS_FTRACE)
> > +CFLAGS_REMOVE_purgatory.o      += $(CC_FLAGS_FTRACE)
> > +CFLAGS_REMOVE_string.o         += $(CC_FLAGS_FTRACE)
> > +CFLAGS_REMOVE_kexec-purgatory.o        += $(CC_FLAGS_FTRACE)
> > +endif
> > +
> > +ifdef CONFIG_STACKPROTECTOR
> > +CFLAGS_REMOVE_sha256.o         += -fstack-protector
> > +CFLAGS_REMOVE_purgatory.o      += -fstack-protector
> > +CFLAGS_REMOVE_string.o         += -fstack-protector
> > +CFLAGS_REMOVE_kexec-purgatory.o        += -fstack-protector
> > +endif
> > +
> > +ifdef CONFIG_STACKPROTECTOR_STRONG
> > +CFLAGS_REMOVE_sha256.o         += -fstack-protector-strong
> > +CFLAGS_REMOVE_purgatory.o      += -fstack-protector-strong
> > +CFLAGS_REMOVE_string.o         += -fstack-protector-strong
> > +CFLAGS_REMOVE_kexec-purgatory.o        += -fstack-protector-strong
> > +endif
> > +
> > +ifdef CONFIG_RETPOLINE
> > +CFLAGS_REMOVE_sha256.o         += $(RETPOLINE_CFLAGS)
> > +CFLAGS_REMOVE_purgatory.o      += $(RETPOLINE_CFLAGS)
> > +CFLAGS_REMOVE_string.o         += $(RETPOLINE_CFLAGS)
> > +CFLAGS_REMOVE_kexec-purgatory.o        += $(RETPOLINE_CFLAGS)
> > +endif
> >
> >  $(obj)/purgatory.ro: $(PURGATORY_OBJS) FORCE
> >                 $(call if_changed,ld)
> >
>
>
> --
> Thanks,
> ~Nick Desaulniers

^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2019-08-13 20:37 UTC | newest]

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2019-08-13 18:40 FAILED: patch "[PATCH] x86/purgatory: Use CFLAGS_REMOVE rather than reset" failed to apply to 4.9-stable tree gregkh
2019-08-13 20:29 ` Nick Desaulniers
2019-08-13 20:37   ` Vaibhav Rustagi

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