On Thu, May 16, 2019 at 09:06:13PM -0700, Nathan Chancellor wrote:
> On Fri, May 17, 2019 at 12:10:02AM +0000, Sasha Levin wrote:
> > Hi,
> >
> > [This is an automated email]
> >
> > This commit has been processed because it contains a -stable tag.
> > The stable tag indicates that it's relevant for the following trees: all
>
> Nick, the stable tag should probably specify 4.8+ since the commit it
> fixes came in during 4.8-rc1.
>
> Cc: stable@xxxxxxxxxxxxxxx # 4.8+
>
> Might also help to add:
>
> Fixes: 9a49a528dcf3 ("lkdtm: add function for testing .rodata section")
>
> >
> > The bot has tested the following trees: v5.1.2, v5.0.16, v4.19.43, v4.14.119, v4.9.176, v4.4.179, v3.18.140.
> >
> > v5.1.2: Build OK!
> > v5.0.16: Build OK!
> > v4.19.43: Build OK!
> > v4.14.119: Failed to apply! Possible dependencies:
> > 039a1c42058d ("lkdtm: Relocate code to subdirectory")
>
> However, it will still need a manual backport because of the lack of
> this commit. I've attached the current patch backported for reference,
Would help if I actually did this... :^)
> the git am flags '-3 -p4 --directory=drivers/misc' help get it proper
> then the conflict is rather easy to resolve.
>
> Thanks,
> Nathan
>From 10c0a74a8d92669b91b66efe6b72550fc24e8e7d Mon Sep 17 00:00:00 2001
From: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Date: Wed, 15 May 2019 11:24:41 -0700
Subject: [PATCH] lkdtm: support llvm-objcopy
With CONFIG_LKDTM=y and make OBJCOPY=llvm-objcopy, llvm-objcopy errors:
llvm-objcopy: error: --set-section-flags=.text conflicts with
--rename-section=.text=.rodata
Rather than support setting flags then renaming sections vs renaming
then setting flags, it's simpler to just change both at the same time
via --rename-section. Adding the load flag is required for GNU objcopy
to mark .rodata Type as PROGBITS after the rename.
This can be verified with:
$ readelf -S drivers/misc/lkdtm/rodata_objcopy.o
...
Section Headers:
[Nr] Name Type Address Offset
Size EntSize Flags Link Info Align
...
[ 1] .rodata PROGBITS 0000000000000000 00000040
0000000000000004 0000000000000000 A 0 0 4
...
Which shows that .text is now renamed .rodata, the alloc flag A is set,
the type is PROGBITS, and the section is not flagged as writeable W.
Cc: stable@xxxxxxxxxxxxxxx
Link: https://sourceware.org/bugzilla/show_bug.cgi?id=24554
Link: https://github.com/ClangBuiltLinux/linux/issues/448
Reported-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
Suggested-by: Alan Modra <amodra@xxxxxxxxx>
Suggested-by: Jordan Rupprect <rupprecht@xxxxxxxxxx>
Suggested-by: Kees Cook <keescook@xxxxxxxxxxxx>
Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>
Reviewed-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
Signed-off-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Signed-off-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
---
drivers/misc/Makefile | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index c3c8624f4d95..805835c2b99b 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -70,8 +70,7 @@ KCOV_INSTRUMENT_lkdtm_rodata.o := n
OBJCOPYFLAGS :=
OBJCOPYFLAGS_lkdtm_rodata_objcopy.o := \
- --set-section-flags .text=alloc,readonly \
- --rename-section .text=.rodata
+ --rename-section .text=.rodata,alloc,readonly,load
targets += lkdtm_rodata.o lkdtm_rodata_objcopy.o
$(obj)/lkdtm_rodata_objcopy.o: $(obj)/lkdtm_rodata.o FORCE
$(call if_changed,objcopy)
--
2.22.0.rc0
