[PATCH mips-next] vmlinux.lds.h: catch more UBSAN symbols into .data

[PATCH mips-next] vmlinux.lds.h: catch more UBSAN symbols into .data

[Alexander Lobakin]

LKP triggered lots of LD orphan warnings [0]:

mipsel-linux-ld: warning: orphan section `.data.$Lubsan_data299' from
`init/do_mounts_rd.o' being placed in section `.data.$Lubsan_data299'
mipsel-linux-ld: warning: orphan section `.data.$Lubsan_data183' from
`init/do_mounts_rd.o' being placed in section `.data.$Lubsan_data183'
mipsel-linux-ld: warning: orphan section `.data.$Lubsan_type3' from
`init/do_mounts_rd.o' being placed in section `.data.$Lubsan_type3'
mipsel-linux-ld: warning: orphan section `.data.$Lubsan_type2' from
`init/do_mounts_rd.o' being placed in section `.data.$Lubsan_type2'
mipsel-linux-ld: warning: orphan section `.data.$Lubsan_type0' from
`init/do_mounts_rd.o' being placed in section `.data.$Lubsan_type0'

[...]

Seems like "unnamed data" isn't the only type of symbols that UBSAN
instrumentation can emit.
Catch these into .data with the wildcard as well.

[0] https://lore.kernel.org/linux-mm/202102160741.k57GCNSR-lkp@intel.com

Fixes: f41b233de0ae ("vmlinux.lds.h: catch UBSAN's "unnamed data" into data")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Alexander Lobakin <alobakin@pm.me>
---
 include/asm-generic/vmlinux.lds.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index cc659e77fcb0..83537e5ee78f 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -95,7 +95,7 @@
  */
 #ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION
 #define TEXT_MAIN .text .text.[0-9a-zA-Z_]*
-#define DATA_MAIN .data .data.[0-9a-zA-Z_]* .data..L* .data..compoundliteral* .data.$__unnamed_*
+#define DATA_MAIN .data .data.[0-9a-zA-Z_]* .data..L* .data..compoundliteral* .data.$__unnamed_* .data.$Lubsan_*
 #define SDATA_MAIN .sdata .sdata.[0-9a-zA-Z_]*
 #define RODATA_MAIN .rodata .rodata.[0-9a-zA-Z_]* .rodata..L*
 #define BSS_MAIN .bss .bss.[0-9a-zA-Z_]* .bss..compoundliteral*
-- 
2.30.1

Re: [PATCH mips-next] vmlinux.lds.h: catch more UBSAN symbols into .data

[Thomas Bogendoerfer]

On Tue, Feb 16, 2021 at 08:55:25AM +0000, Alexander Lobakin wrote:
> LKP triggered lots of LD orphan warnings [0]:
> 
> mipsel-linux-ld: warning: orphan section `.data.$Lubsan_data299' from
> `init/do_mounts_rd.o' being placed in section `.data.$Lubsan_data299'
> mipsel-linux-ld: warning: orphan section `.data.$Lubsan_data183' from
> `init/do_mounts_rd.o' being placed in section `.data.$Lubsan_data183'
> mipsel-linux-ld: warning: orphan section `.data.$Lubsan_type3' from
> `init/do_mounts_rd.o' being placed in section `.data.$Lubsan_type3'
> mipsel-linux-ld: warning: orphan section `.data.$Lubsan_type2' from
> `init/do_mounts_rd.o' being placed in section `.data.$Lubsan_type2'
> mipsel-linux-ld: warning: orphan section `.data.$Lubsan_type0' from
> `init/do_mounts_rd.o' being placed in section `.data.$Lubsan_type0'
> 
> [...]
> 
> Seems like "unnamed data" isn't the only type of symbols that UBSAN
> instrumentation can emit.
> Catch these into .data with the wildcard as well.
> 
> [0] https://lore.kernel.org/linux-mm/202102160741.k57GCNSR-lkp@intel.com
> 
> Fixes: f41b233de0ae ("vmlinux.lds.h: catch UBSAN's "unnamed data" into data")
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Alexander Lobakin <alobakin@pm.me>
> ---
>  include/asm-generic/vmlinux.lds.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

applied to mips-next.

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]

Re: [PATCH mips-next] vmlinux.lds.h: catch more UBSAN symbols into .data

[Nick Desaulniers]

On Tue, Feb 16, 2021 at 12:55 AM Alexander Lobakin <alobakin@pm.me> wrote:
>
> LKP triggered lots of LD orphan warnings [0]:

Thanks for the patch, just some questions.

With which linker?  Was there a particular config from the bot's
report that triggered this?

>
> mipsel-linux-ld: warning: orphan section `.data.$Lubsan_data299' from
> `init/do_mounts_rd.o' being placed in section `.data.$Lubsan_data299'
> mipsel-linux-ld: warning: orphan section `.data.$Lubsan_data183' from
> `init/do_mounts_rd.o' being placed in section `.data.$Lubsan_data183'
> mipsel-linux-ld: warning: orphan section `.data.$Lubsan_type3' from
> `init/do_mounts_rd.o' being placed in section `.data.$Lubsan_type3'
> mipsel-linux-ld: warning: orphan section `.data.$Lubsan_type2' from
> `init/do_mounts_rd.o' being placed in section `.data.$Lubsan_type2'
> mipsel-linux-ld: warning: orphan section `.data.$Lubsan_type0' from
> `init/do_mounts_rd.o' being placed in section `.data.$Lubsan_type0'
>
> [...]
>
> Seems like "unnamed data" isn't the only type of symbols that UBSAN
> instrumentation can emit.
> Catch these into .data with the wildcard as well.
>
> [0] https://lore.kernel.org/linux-mm/202102160741.k57GCNSR-lkp@intel.com
>
> Fixes: f41b233de0ae ("vmlinux.lds.h: catch UBSAN's "unnamed data" into data")
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Alexander Lobakin <alobakin@pm.me>
> ---
>  include/asm-generic/vmlinux.lds.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
> index cc659e77fcb0..83537e5ee78f 100644
> --- a/include/asm-generic/vmlinux.lds.h
> +++ b/include/asm-generic/vmlinux.lds.h
> @@ -95,7 +95,7 @@
>   */
>  #ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION
>  #define TEXT_MAIN .text .text.[0-9a-zA-Z_]*
> -#define DATA_MAIN .data .data.[0-9a-zA-Z_]* .data..L* .data..compoundliteral* .data.$__unnamed_*
> +#define DATA_MAIN .data .data.[0-9a-zA-Z_]* .data..L* .data..compoundliteral* .data.$__unnamed_* .data.$Lubsan_*

Are these sections only created when
CONFIG_LD_DEAD_CODE_DATA_ELIMINATION is selected?  (Same with
.data.$__unnamed_*)

>  #define SDATA_MAIN .sdata .sdata.[0-9a-zA-Z_]*
>  #define RODATA_MAIN .rodata .rodata.[0-9a-zA-Z_]* .rodata..L*
>  #define BSS_MAIN .bss .bss.[0-9a-zA-Z_]* .bss..compoundliteral*
> --
> 2.30.1
>
>


-- 
Thanks,
~Nick Desaulniers

Re: [PATCH mips-next] vmlinux.lds.h: catch more UBSAN symbols into .data

[Nathan Chancellor]

On Tue, Feb 16, 2021 at 09:56:32AM -0800, 'Nick Desaulniers' via Clang Built Linux wrote:
> On Tue, Feb 16, 2021 at 12:55 AM Alexander Lobakin <alobakin@pm.me> wrote:
> >
> > LKP triggered lots of LD orphan warnings [0]:
> 
> Thanks for the patch, just some questions.
> 
> With which linker?  Was there a particular config from the bot's
> report that triggered this?

Looks like GNU ld 2.34 (see below).

> >
> > mipsel-linux-ld: warning: orphan section `.data.$Lubsan_data299' from
> > `init/do_mounts_rd.o' being placed in section `.data.$Lubsan_data299'
> > mipsel-linux-ld: warning: orphan section `.data.$Lubsan_data183' from
> > `init/do_mounts_rd.o' being placed in section `.data.$Lubsan_data183'
> > mipsel-linux-ld: warning: orphan section `.data.$Lubsan_type3' from
> > `init/do_mounts_rd.o' being placed in section `.data.$Lubsan_type3'
> > mipsel-linux-ld: warning: orphan section `.data.$Lubsan_type2' from
> > `init/do_mounts_rd.o' being placed in section `.data.$Lubsan_type2'
> > mipsel-linux-ld: warning: orphan section `.data.$Lubsan_type0' from
> > `init/do_mounts_rd.o' being placed in section `.data.$Lubsan_type0'
> >
> > [...]
> >
> > Seems like "unnamed data" isn't the only type of symbols that UBSAN
> > instrumentation can emit.
> > Catch these into .data with the wildcard as well.
> >
> > [0] https://lore.kernel.org/linux-mm/202102160741.k57GCNSR-lkp@intel.com
> >
> > Fixes: f41b233de0ae ("vmlinux.lds.h: catch UBSAN's "unnamed data" into data")
> > Reported-by: kernel test robot <lkp@intel.com>
> > Signed-off-by: Alexander Lobakin <alobakin@pm.me>
> > ---
> >  include/asm-generic/vmlinux.lds.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
> > index cc659e77fcb0..83537e5ee78f 100644
> > --- a/include/asm-generic/vmlinux.lds.h
> > +++ b/include/asm-generic/vmlinux.lds.h
> > @@ -95,7 +95,7 @@
> >   */
> >  #ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION
> >  #define TEXT_MAIN .text .text.[0-9a-zA-Z_]*
> > -#define DATA_MAIN .data .data.[0-9a-zA-Z_]* .data..L* .data..compoundliteral* .data.$__unnamed_*
> > +#define DATA_MAIN .data .data.[0-9a-zA-Z_]* .data..L* .data..compoundliteral* .data.$__unnamed_* .data.$Lubsan_*
> 
> Are these sections only created when
> CONFIG_LD_DEAD_CODE_DATA_ELIMINATION is selected?  (Same with
> .data.$__unnamed_*)

Most likely, as that config is set in the problematic config. My guess
is that these are GCC's equivalent of Clang's .data.$__unnamed_...

$ crl https://lore.kernel.org/linux-mm/202102160741.k57GCNSR-lkp@intel.com/2-a.bin | gzip -d | rg "CONFIG_LD_DEAD_CODE|CONFIG_LD_VERSION"
CONFIG_LD_VERSION=234000000
CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y

> >  #define SDATA_MAIN .sdata .sdata.[0-9a-zA-Z_]*
> >  #define RODATA_MAIN .rodata .rodata.[0-9a-zA-Z_]* .rodata..L*
> >  #define BSS_MAIN .bss .bss.[0-9a-zA-Z_]* .bss..compoundliteral*
> > --
> > 2.30.1
> >
> >
> 
> 
> -- 
> Thanks,
> ~Nick Desaulniers
> 

Re: [PATCH mips-next] vmlinux.lds.h: catch more UBSAN symbols into .data

[Alexander Lobakin]

From: Nick Desaulniers <ndesaulniers@google.com>
Date: Tue, 16 Feb 2021 09:56:32 -0800

> On Tue, Feb 16, 2021 at 12:55 AM Alexander Lobakin <alobakin@pm.me> wrote:
> >
> > LKP triggered lots of LD orphan warnings [0]:
> 
> Thanks for the patch, just some questions.
> 
> With which linker?  Was there a particular config from the bot's
> report that triggered this?

All the info can be found by going through the link from the commit
message. Compiler was GCC 9.3, so I suppose BFD was used as a linker.
I mentioned CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y in the attached
dotconfig, the warnings and the fix are relevant only for this case.

> >
> > mipsel-linux-ld: warning: orphan section `.data.$Lubsan_data299' from
> > `init/do_mounts_rd.o' being placed in section `.data.$Lubsan_data299'
> > mipsel-linux-ld: warning: orphan section `.data.$Lubsan_data183' from
> > `init/do_mounts_rd.o' being placed in section `.data.$Lubsan_data183'
> > mipsel-linux-ld: warning: orphan section `.data.$Lubsan_type3' from
> > `init/do_mounts_rd.o' being placed in section `.data.$Lubsan_type3'
> > mipsel-linux-ld: warning: orphan section `.data.$Lubsan_type2' from
> > `init/do_mounts_rd.o' being placed in section `.data.$Lubsan_type2'
> > mipsel-linux-ld: warning: orphan section `.data.$Lubsan_type0' from
> > `init/do_mounts_rd.o' being placed in section `.data.$Lubsan_type0'
> >
> > [...]
> >
> > Seems like "unnamed data" isn't the only type of symbols that UBSAN
> > instrumentation can emit.
> > Catch these into .data with the wildcard as well.
> >
> > [0] https://lore.kernel.org/linux-mm/202102160741.k57GCNSR-lkp@intel.com
> >
> > Fixes: f41b233de0ae ("vmlinux.lds.h: catch UBSAN's "unnamed data" into data")
> > Reported-by: kernel test robot <lkp@intel.com>
> > Signed-off-by: Alexander Lobakin <alobakin@pm.me>
> > ---
> >  include/asm-generic/vmlinux.lds.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
> > index cc659e77fcb0..83537e5ee78f 100644
> > --- a/include/asm-generic/vmlinux.lds.h
> > +++ b/include/asm-generic/vmlinux.lds.h
> > @@ -95,7 +95,7 @@
> >   */
> >  #ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION
> >  #define TEXT_MAIN .text .text.[0-9a-zA-Z_]*
> > -#define DATA_MAIN .data .data.[0-9a-zA-Z_]* .data..L* .data..compoundliteral* .data.$__unnamed_*
> > +#define DATA_MAIN .data .data.[0-9a-zA-Z_]* .data..L* .data..compoundliteral* .data.$__unnamed_* .data.$Lubsan_*
> 
> Are these sections only created when
> CONFIG_LD_DEAD_CODE_DATA_ELIMINATION is selected?  (Same with
> .data.$__unnamed_*)
> 
> >  #define SDATA_MAIN .sdata .sdata.[0-9a-zA-Z_]*
> >  #define RODATA_MAIN .rodata .rodata.[0-9a-zA-Z_]* .rodata..L*
> >  #define BSS_MAIN .bss .bss.[0-9a-zA-Z_]* .bss..compoundliteral*
> > --
> > 2.30.1
> >
> >
> 
> 
> -- 
> Thanks,
> ~Nick Desaulniers

Al