DWARF2 only supports one section per compilation unit #716

tpimh · 2019-09-27T08:01:32Z

Same warnings as #607 when compiling ARM64 kernel using integrated assembler.

arch/arm64/kernel/vdso/vdso.S:14:2: warning: DWARF2 only supports one section per compilation unit
 .section .rodata
 ^

arch/arm64/kernel/head.S:62:2: warning: DWARF2 only supports one section per compilation unit
 .section ".head.text","ax"
 ^
/tmp/head-9725f8.s:1028:2: warning: DWARF2 only supports one section per compilation unit
 .section ".init.text","ax"
 ^
/tmp/head-9725f8.s:1275:2: warning: DWARF2 only supports one section per compilation unit
 .section ".idmap.text","awx"
 ^
<instantiation>:3:2: warning: DWARF2 only supports one section per compilation unit
 .section ___ksymtab+kimage_vaddr,"a"
 ^
/tmp/head-9725f8.s:1279:1: note: while in macro instantiation
___EXPORT_SYMBOL kimage_vaddr, kimage_vaddr,
^
<instantiation>:8:2: warning: DWARF2 only supports one section per compilation unit
 .section __ksymtab_strings,"a"
 ^
/tmp/head-9725f8.s:1279:1: note: while in macro instantiation
___EXPORT_SYMBOL kimage_vaddr, kimage_vaddr,
^
arch/arm64/kernel/head.S:662:2: warning: DWARF2 only supports one section per compilation unit
 .pushsection ".mmuoff.data.write", "aw"
 ^

<instantiation>:2:2: warning: DWARF2 only supports one section per compilation unit
 .pushsection .altinstructions, "a"
 ^
arch/arm64/mm/cache.S:42:1: note: while in macro instantiation
alternative_if 27
^
<instantiation>:5:2: warning: DWARF2 only supports one section per compilation unit
 .pushsection .altinstr_replacement, "ax"
 ^
arch/arm64/mm/cache.S:42:1: note: while in macro instantiation
alternative_if 27
^
<instantiation>:1:1: warning: DWARF2 only supports one section per compilation unit
.pushsection __ex_table, "a"
^
<instantiation>:5:20: note: while in macro instantiation
9999: ic ivau, x3; _asm_extable 9999b, 9f
                   ^
arch/arm64/mm/cache.S:61:2: note: while in macro instantiation
 invalidate_icache_by_line x0, x1, x2, x3, 9f
 ^

The text was updated successfully, but these errors were encountered:

nickdesaulniers · 2020-03-19T23:18:47Z

@jcai19 so for this, the warning is not wrong but:

it's not named, so we can't turn it off explicitly.
without .cfi_* directives, I'm not sure that debug sections get created, so who cares about dwarf if we're not emitting debug info? (Maybe we are somehow, and I'm wrong).

ihalip · 2020-03-20T08:34:43Z

Old proposed fix: https://reviews.llvm.org/D6379

nickdesaulniers · 2020-03-20T21:45:34Z

Great find! Maybe I can "commandeer" that revision.

nickdesaulniers · 2020-03-21T00:31:51Z

Jotting down some notes:

the top level Makefile sets KBUILD_AFLAGS += -Wa,-gdwarf-2, so all assembly files are assembled in dwarf2 mode.
most .s/.S files don't use any assembler directives that would produce dwarf debug sections:
for f in $(find arch/ -name \*.S); do grep -l "cfi" $f; done produces 23 files that have any .cfi related directives. I'm not sure if there's other assembler directives other than the many .cfi ones that produce debug info. (More info on cfi directives.
the presence of these directives produces .debug_line, .debug_info, .debug_abbrev, .debug_aranges, .debug_str, and .eh_frame (and their .rela equivalents) in .o binaries.
without cfi directives, it seems the .debug_line is still produced.
these can be dumped with objdump -W foo.o. It seems that llvm-objdump doesn't implement -W :( Also, aarch64-linux-gnu-readelf --debug-dump=line for non cfi assembler files.

m-gupta · 2020-10-21T21:59:30Z

Chrome OS has moved to dwarf-4 (CONFIG_DEBUG_INFO_DWARF4=y). Does these warnings also trigger for dwarf4 ?

nickdesaulniers · 2020-10-22T00:58:14Z

No

bwendling · 2020-10-23T09:05:30Z

It turns out that pahole has issue with this:

die__process_unit: DW_TAG_label (0xa) @ <0x7689bf6> not handled!

dileks · 2020-10-26T07:42:24Z

When I experimented and later switched to CONFIG_DEBUG_INFO_DWARF4=y I have seen this, too.

One result was the simplification of DEBUG_INFO Kconfig handling (see [1] which is now in Linux v5.10-rc1).

The commit in [1] also points to my introduction of CONFIG_DEBUG_INFO_AS_DWARF2 and CONFIG_DEBUG_INFO_AS_DWARF4 (see [2]).
Unfortunately on kbuild ML I got no reply how to go further with this.

We have more places where KBUILD_AFLAGS += -Wa,-gdwarf-2 is used.

Please, let me know what you think.

[1] https://git.kernel.org/linus/695afd3d7d58ec3044d25c9d2fe384ab8627fd20
[2] https://patchwork.kernel.org/project/linux-kbuild/patch/CA+icZUV85LS08Y2qJ-mheecCrzZmCTV4B5x9kh=BGCUzQVOKaA@mail.gmail.com/

m-gupta · 2020-10-27T00:30:23Z

Adding @jcai19

dileks · 2020-10-28T10:29:35Z

Some notes:

[ include/asm/dwarf2.h ]

We have arch/x86/include/asm/dwarf2.h included in some .S files - do we need something similiar like dwarf4.h for x86 arch?

$ git grep dwarf2.h arch/
arch/x86/entry/vdso/vdso32/system_call.S:#include <asm/dwarf2.h>
arch/x86/include/asm/dwarf2.h:#warning "asm/dwarf2.h should be only included in pure assembly files"
arch/x86/lib/retpoline.S:#include <asm/dwarf2.h>

Do we need such an include also for other archs like arm/arm64?

[ -fno-dwarf2-cfi-asm ]

We have places in arm/arm64 arch where we pass -fno-dwarf2-cfi-asm - is that in the CONFIG_DEBUG_INFO=y case or in general?

[ Makefile ]

Passing DWARF-2 assembler option KBUILD_AFLAGS += -Wa,-gdwarf-2 in top-level Makefile is IMHO not correct when using CONFIG_DEBUG_INFO=y and especially together with CONFIG_DEBUG_INFO_DWARF4=y.

dileks · 2020-10-28T10:36:46Z

My approach looks like this (here: on top of Linux v5.10-rc1):

diff --git a/Makefile b/Makefile
--- a/Makefile
+++ b/Makefile
@@ -828,7 +828,11 @@ else
 DEBUG_CFLAGS   += -g
 endif
 
+ifdef CONFIG_DEBUG_INFO_AS_DWARF2
 KBUILD_AFLAGS  += -Wa,-gdwarf-2
+else ifdef CONFIG_DEBUG_INFO_AS_DWARF4
+KBUILD_AFLAGS  += -Wa,-gdwarf-4
+endif
 
 ifdef CONFIG_DEBUG_INFO_DWARF4
 DEBUG_CFLAGS   += -gdwarf-4
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -256,9 +256,22 @@ config DEBUG_INFO_SPLIT
          to know about the .dwo files and include them.
          Incompatible with older versions of ccache.
 
+config DEBUG_INFO_AS_DWARF2
+       bool "Use DWARF-2 assembler option with debuginfo"
+       depends on $(cc-option,-Wa$(comma)-gdwarf-2)
+       help
+         Set DWARF-2 assembler option with debuginfo
+
+config DEBUG_INFO_AS_DWARF4
+       bool "Use DWARF-4 assembler option with debuginfo"
+       depends on $(cc-option,-Wa$(comma)-gdwarf-4)
+       help
+         Set DWARF-4 assembler option with debuginfo
+
 config DEBUG_INFO_DWARF4
        bool "Generate dwarf4 debuginfo"
        depends on $(cc-option,-gdwarf-4)
+       select DEBUG_INFO_AS_DWARF4
        help
          Generate dwarf4 debug info. This requires recent versions
          of gcc and gdb. It makes the debug information larger.

Tested on all my Linux 5.9 rcX and final builds for x86 64bit.

dileks · 2020-10-28T10:43:04Z

Sidenote:
My experiences with DWARF-4 was LLVM with ld.lld version 11.0.0 was reducing debug-info (binary) size better that GCC version 10.2 with GNU/ld.bfd v2.35.1.

nickdesaulniers · 2020-10-29T17:37:45Z

My approach looks like this

I'd rather keep the assembler's DWARF version in sync with the compilers. There's no real need to mix and match versions.

Also, by not explicitly specifying -gdwarf-2 when CONFIG_DEBUG_INFO_DWARF4 is not set, clang still defaults to DWARF4, so upstream is currently broken in that regard.

nickdesaulniers · 2020-11-04T00:56:31Z

Sent upstream (https://lore.kernel.org/lkml/20201104005343.4192504-3-ndesaulniers@google.com/T/#u) as part of my series on DWARF v5 (https://lore.kernel.org/lkml/20201104005343.4192504-1-ndesaulniers@google.com/T/#u).

Clang's integrated assembler produces the warning for assembly files: warning: DWARF2 only supports one section per compilation unit If -Wa,-gdwarf-* is unspecified, then debug info is not emitted. This will be re-enabled for new DWARF versions in a follow up patch. Enables defconfig+CONFIG_DEBUG_INFO to build cleanly with LLVM=1 LLVM_IAS=1 for x86_64 and arm64. Cc: <stable@vger.kernel.org> Link: ClangBuiltLinux#716 Reported-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Dmitry Golovin <dima@golovin.in> Suggested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>

Clang's integrated assembler produces the warning for assembly files: warning: DWARF2 only supports one section per compilation unit If -Wa,-gdwarf-* is unspecified, then debug info is not emitted for assembly sources (it is still emitted for C sources). This will be re-enabled for newer DWARF versions in a follow up patch. Enables defconfig+CONFIG_DEBUG_INFO to build cleanly with LLVM=1 LLVM_IAS=1 for x86_64 and arm64. Reported-by: Dmitry Golovin <dima@golovin.in> Reported-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Dmitry Golovin <dima@golovin.in> Suggested-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Cc: <stable@vger.kernel.org> Link: ClangBuiltLinux/linux#716 Bug: 141693040 Link: https://lore.kernel.org/lkml/20201109183528.1391885-1-ndesaulniers@google.com/ Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: I55c8ad79dfeaae478c8de52d484e76fb2e37c194

Clang's integrated assembler produces the warning for assembly files: warning: DWARF2 only supports one section per compilation unit If -Wa,-gdwarf-* is unspecified, then debug info is not emitted for assembly sources (it is still emitted for C sources). This will be re-enabled for newer DWARF versions in a follow up patch. Enables defconfig+CONFIG_DEBUG_INFO to build cleanly with LLVM=1 LLVM_IAS=1 for x86_64 and arm64. Reported-by: Dmitry Golovin <dima@golovin.in> Reported-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Dmitry Golovin <dima@golovin.in> Suggested-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Cc: <stable@vger.kernel.org> Link: ClangBuiltLinux/linux#716 Bug: 141693040 Link: https://lore.kernel.org/lkml/20201109183528.1391885-1-ndesaulniers@google.com/ Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: I55c8ad79dfeaae478c8de52d484e76fb2e37c194 Signed-off-by: Matthias Maennich <maennich@google.com>

commit b8a9092330da2030496ff357272f342eb970d51b upstream. Clang's integrated assembler produces the warning for assembly files: warning: DWARF2 only supports one section per compilation unit If -Wa,-gdwarf-* is unspecified, then debug info is not emitted for assembly sources (it is still emitted for C sources). This will be re-enabled for newer DWARF versions in a follow up patch. Enables defconfig+CONFIG_DEBUG_INFO to build cleanly with LLVM=1 LLVM_IAS=1 for x86_64 and arm64. Cc: <stable@vger.kernel.org> Link: ClangBuiltLinux/linux#716 Reported-by: Dmitry Golovin <dima@golovin.in> Reported-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Dmitry Golovin <dima@golovin.in> Suggested-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> [nd: backport to avoid conflicts from: commit 10e68b02c861 ("Makefile: support compressed debug info") commit 7b16994437c7 ("Makefile: Improve compressed debug info support detection") commit 695afd3d7d58 ("kbuild: Simplify DEBUG_INFO Kconfig handling")] Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Clang's integrated assembler produces the warning for assembly files: warning: DWARF2 only supports one section per compilation unit If -Wa,-gdwarf-* is unspecified, then debug info is not emitted for assembly sources (it is still emitted for C sources). This will be re-enabled for newer DWARF versions in a follow up patch. Enables defconfig+CONFIG_DEBUG_INFO to build cleanly with LLVM=1 LLVM_IAS=1 for x86_64 and arm64. Reported-by: Dmitry Golovin <dima@golovin.in> Reported-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Dmitry Golovin <dima@golovin.in> Suggested-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Cc: <stable@vger.kernel.org> Link: ClangBuiltLinux/linux#716 Bug: 141693040 Link: https://lore.kernel.org/lkml/20201109183528.1391885-1-ndesaulniers@google.com/ Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: I55c8ad79dfeaae478c8de52d484e76fb2e37c194

commit b8a9092330da2030496ff357272f342eb970d51b upstream. Clang's integrated assembler produces the warning for assembly files: warning: DWARF2 only supports one section per compilation unit If -Wa,-gdwarf-* is unspecified, then debug info is not emitted for assembly sources (it is still emitted for C sources). This will be re-enabled for newer DWARF versions in a follow up patch. Enables defconfig+CONFIG_DEBUG_INFO to build cleanly with LLVM=1 LLVM_IAS=1 for x86_64 and arm64. Cc: <stable@vger.kernel.org> Link: ClangBuiltLinux/linux#716 Reported-by: Dmitry Golovin <dima@golovin.in> Reported-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Dmitry Golovin <dima@golovin.in> Suggested-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Change-Id: I630d909159c9dcaae0c4c7e50d9542c37424416d Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> [nd: backport to avoid conflicts from: commit 10e68b02c861 ("Makefile: support compressed debug info") commit 7b16994437c7 ("Makefile: Improve compressed debug info support detection") commit 695afd3d7d58 ("kbuild: Simplify DEBUG_INFO Kconfig handling")] Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Clang's integrated assembler produces the warning for assembly files: warning: DWARF2 only supports one section per compilation unit If -Wa,-gdwarf-* is unspecified, then debug info is not emitted for assembly sources (it is still emitted for C sources). This will be re-enabled for newer DWARF versions in a follow up patch. Enables defconfig+CONFIG_DEBUG_INFO to build cleanly with LLVM=1 LLVM_IAS=1 for x86_64 and arm64. Reported-by: Dmitry Golovin <dima@golovin.in> Reported-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Dmitry Golovin <dima@golovin.in> Suggested-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Cc: <stable@vger.kernel.org> Link: ClangBuiltLinux/linux#716 Bug: 141693040 Link: https://lore.kernel.org/lkml/20201109183528.1391885-1-ndesaulniers@google.com/ Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: I55c8ad79dfeaae478c8de52d484e76fb2e37c194

commit b8a9092330da2030496ff357272f342eb970d51b upstream. Clang's integrated assembler produces the warning for assembly files: warning: DWARF2 only supports one section per compilation unit If -Wa,-gdwarf-* is unspecified, then debug info is not emitted for assembly sources (it is still emitted for C sources). This will be re-enabled for newer DWARF versions in a follow up patch. Enables defconfig+CONFIG_DEBUG_INFO to build cleanly with LLVM=1 LLVM_IAS=1 for x86_64 and arm64. Cc: <stable@vger.kernel.org> Link: ClangBuiltLinux/linux#716 Reported-by: Dmitry Golovin <dima@golovin.in> Reported-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Dmitry Golovin <dima@golovin.in> Suggested-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Change-Id: I630d909159c9dcaae0c4c7e50d9542c37424416d Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> [nd: backport to avoid conflicts from: commit 10e68b02c861 ("Makefile: support compressed debug info") commit 7b16994437c7 ("Makefile: Improve compressed debug info support detection") commit 695afd3d7d58 ("kbuild: Simplify DEBUG_INFO Kconfig handling")] Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit b8a9092330da2030496ff357272f342eb970d51b upstream. Clang's integrated assembler produces the warning for assembly files: warning: DWARF2 only supports one section per compilation unit If -Wa,-gdwarf-* is unspecified, then debug info is not emitted for assembly sources (it is still emitted for C sources). This will be re-enabled for newer DWARF versions in a follow up patch. Enables defconfig+CONFIG_DEBUG_INFO to build cleanly with LLVM=1 LLVM_IAS=1 for x86_64 and arm64. Cc: <stable@vger.kernel.org> Link: ClangBuiltLinux/linux#716 Reported-by: Dmitry Golovin <dima@golovin.in> Reported-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Dmitry Golovin <dima@golovin.in> Suggested-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> [nd: backport to avoid conflicts from: commit 10e68b02c861 ("Makefile: support compressed debug info") commit 7b16994437c7 ("Makefile: Improve compressed debug info support detection") commit 695afd3d7d58 ("kbuild: Simplify DEBUG_INFO Kconfig handling")] Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Change-Id: Ia4da22fe1254ea433d4d346fc24158d66663c11a Signed-off-by: Cyber Knight <cyberknight755@gmail.com>

commit b8a9092330da2030496ff357272f342eb970d51b upstream. Clang's integrated assembler produces the warning for assembly files: warning: DWARF2 only supports one section per compilation unit If -Wa,-gdwarf-* is unspecified, then debug info is not emitted for assembly sources (it is still emitted for C sources). This will be re-enabled for newer DWARF versions in a follow up patch. Enables defconfig+CONFIG_DEBUG_INFO to build cleanly with LLVM=1 LLVM_IAS=1 for x86_64 and arm64. Cc: <stable@vger.kernel.org> Link: ClangBuiltLinux/linux#716 Reported-by: Dmitry Golovin <dima@golovin.in> Reported-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Dmitry Golovin <dima@golovin.in> Suggested-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> [nd: backport to avoid conflicts from: commit 10e68b02c861 ("Makefile: support compressed debug info") commit 7b16994437c7 ("Makefile: Improve compressed debug info support detection") commit 695afd3d7d58 ("kbuild: Simplify DEBUG_INFO Kconfig handling")] Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Change-Id: Ia4da22fe1254ea433d4d346fc24158d66663c11a

Clang's integrated assembler produces the warning for assembly files: warning: DWARF2 only supports one section per compilation unit If -Wa,-gdwarf-* is unspecified, then debug info is not emitted for assembly sources (it is still emitted for C sources). This will be re-enabled for newer DWARF versions in a follow up patch. Enables defconfig+CONFIG_DEBUG_INFO to build cleanly with LLVM=1 LLVM_IAS=1 for x86_64 and arm64. Reported-by: Dmitry Golovin <dima@golovin.in> Reported-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Dmitry Golovin <dima@golovin.in> Suggested-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Cc: <stable@vger.kernel.org> Link: ClangBuiltLinux/linux#716 Bug: 141693040 Link: https://lore.kernel.org/lkml/20201109183528.1391885-1-ndesaulniers@google.com/ Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: I55c8ad79dfeaae478c8de52d484e76fb2e37c194

commit b8a9092330da2030496ff357272f342eb970d51b upstream. Clang's integrated assembler produces the warning for assembly files: warning: DWARF2 only supports one section per compilation unit If -Wa,-gdwarf-* is unspecified, then debug info is not emitted for assembly sources (it is still emitted for C sources). This will be re-enabled for newer DWARF versions in a follow up patch. Enables defconfig+CONFIG_DEBUG_INFO to build cleanly with LLVM=1 LLVM_IAS=1 for x86_64 and arm64. Cc: <stable@vger.kernel.org> Link: ClangBuiltLinux/linux#716 Reported-by: Dmitry Golovin <dima@golovin.in> Reported-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Dmitry Golovin <dima@golovin.in> Suggested-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> [nd: backport to avoid conflicts from: commit 10e68b02c861 ("Makefile: support compressed debug info") commit 7b16994437c7 ("Makefile: Improve compressed debug info support detection") commit 695afd3d7d58 ("kbuild: Simplify DEBUG_INFO Kconfig handling")] Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Change-Id: I88b3045d3bd90ffcf0459b5c1162d11ee138d097

commit b8a9092330da2030496ff357272f342eb970d51b upstream. Clang's integrated assembler produces the warning for assembly files: warning: DWARF2 only supports one section per compilation unit If -Wa,-gdwarf-* is unspecified, then debug info is not emitted for assembly sources (it is still emitted for C sources). This will be re-enabled for newer DWARF versions in a follow up patch. Enables defconfig+CONFIG_DEBUG_INFO to build cleanly with LLVM=1 LLVM_IAS=1 for x86_64 and arm64. Cc: <stable@vger.kernel.org> Link: ClangBuiltLinux/linux#716 Reported-by: Dmitry Golovin <dima@golovin.in> Reported-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Dmitry Golovin <dima@golovin.in> Suggested-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> [nd: backport to avoid conflicts from: commit 10e68b02c861 ("Makefile: support compressed debug info") commit 7b16994437c7 ("Makefile: Improve compressed debug info support detection") commit 695afd3d7d58 ("kbuild: Simplify DEBUG_INFO Kconfig handling")] Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit b8a9092330da2030496ff357272f342eb970d51b upstream. Clang's integrated assembler produces the warning for assembly files: warning: DWARF2 only supports one section per compilation unit If -Wa,-gdwarf-* is unspecified, then debug info is not emitted for assembly sources (it is still emitted for C sources). This will be re-enabled for newer DWARF versions in a follow up patch. Enables defconfig+CONFIG_DEBUG_INFO to build cleanly with LLVM=1 LLVM_IAS=1 for x86_64 and arm64. Cc: <stable@vger.kernel.org> Link: ClangBuiltLinux/linux#716 Reported-by: Dmitry Golovin <dima@golovin.in> Reported-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Dmitry Golovin <dima@golovin.in> Suggested-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> [nd: backport to avoid conflicts from: commit 10e68b02c861 ("Makefile: support compressed debug info") commit 7b16994437c7 ("Makefile: Improve compressed debug info support detection") commit 695afd3d7d58 ("kbuild: Simplify DEBUG_INFO Kconfig handling")] Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Change-Id: Ia4da22fe1254ea433d4d346fc24158d66663c11a Signed-off-by: Rem01Gaming <Rem01_Gaming@proton.me>

commit b8a9092 upstream. Clang's integrated assembler produces the warning for assembly files: warning: DWARF2 only supports one section per compilation unit If -Wa,-gdwarf-* is unspecified, then debug info is not emitted for assembly sources (it is still emitted for C sources). This will be re-enabled for newer DWARF versions in a follow up patch. Enables defconfig+CONFIG_DEBUG_INFO to build cleanly with LLVM=1 LLVM_IAS=1 for x86_64 and arm64. Cc: <stable@vger.kernel.org> Link: ClangBuiltLinux/linux#716 Reported-by: Dmitry Golovin <dima@golovin.in> Reported-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Dmitry Golovin <dima@golovin.in> Suggested-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> [nd: backport to avoid conflicts from: commit 10e68b0 ("Makefile: support compressed debug info") commit 7b16994 ("Makefile: Improve compressed debug info support detection") commit 695afd3 ("kbuild: Simplify DEBUG_INFO Kconfig handling")] Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Change-Id: Ia4da22fe1254ea433d4d346fc24158d66663c11a

commit b8a9092330da2030496ff357272f342eb970d51b upstream. Clang's integrated assembler produces the warning for assembly files: warning: DWARF2 only supports one section per compilation unit If -Wa,-gdwarf-* is unspecified, then debug info is not emitted for assembly sources (it is still emitted for C sources). This will be re-enabled for newer DWARF versions in a follow up patch. Enables defconfig+CONFIG_DEBUG_INFO to build cleanly with LLVM=1 LLVM_IAS=1 for x86_64 and arm64. Cc: <stable@vger.kernel.org> Link: ClangBuiltLinux/linux#716 Reported-by: Dmitry Golovin <dima@golovin.in> Reported-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Dmitry Golovin <dima@golovin.in> Suggested-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> [nd: backport to avoid conflicts from: commit 10e68b02c861 ("Makefile: support compressed debug info") commit 7b16994437c7 ("Makefile: Improve compressed debug info support detection") commit 695afd3d7d58 ("kbuild: Simplify DEBUG_INFO Kconfig handling")] Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit b8a9092330da2030496ff357272f342eb970d51b upstream. Clang's integrated assembler produces the warning for assembly files: warning: DWARF2 only supports one section per compilation unit If -Wa,-gdwarf-* is unspecified, then debug info is not emitted for assembly sources (it is still emitted for C sources). This will be re-enabled for newer DWARF versions in a follow up patch. Enables defconfig+CONFIG_DEBUG_INFO to build cleanly with LLVM=1 LLVM_IAS=1 for x86_64 and arm64. Cc: <stable@vger.kernel.org> Link: ClangBuiltLinux/linux#716 Reported-by: Dmitry Golovin <dima@golovin.in> Reported-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Dmitry Golovin <dima@golovin.in> Suggested-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> [nd: backport to avoid conflicts from: commit 10e68b02c861 ("Makefile: support compressed debug info") commit 7b16994437c7 ("Makefile: Improve compressed debug info support detection") commit 695afd3d7d58 ("kbuild: Simplify DEBUG_INFO Kconfig handling")] Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Change-Id: Ia4da22fe1254ea433d4d346fc24158d66663c11a Signed-off-by: savie <ntop_one@yahoo.co.id>

Clang's integrated assembler produces the warning for assembly files: warning: DWARF2 only supports one section per compilation unit If -Wa,-gdwarf-* is unspecified, then debug info is not emitted for assembly sources (it is still emitted for C sources). This will be re-enabled for newer DWARF versions in a follow up patch. Enables defconfig+CONFIG_DEBUG_INFO to build cleanly with LLVM=1 LLVM_IAS=1 for x86_64 and arm64. Reported-by: Dmitry Golovin <dima@golovin.in> Reported-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Dmitry Golovin <dima@golovin.in> Suggested-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Cc: <stable@vger.kernel.org> Link: ClangBuiltLinux/linux#716 Bug: 141693040 Link: https://lore.kernel.org/lkml/20201109183528.1391885-1-ndesaulniers@google.com/ Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Change-Id: I55c8ad79dfeaae478c8de52d484e76fb2e37c194

commit b8a9092330da2030496ff357272f342eb970d51b upstream. Clang's integrated assembler produces the warning for assembly files: warning: DWARF2 only supports one section per compilation unit If -Wa,-gdwarf-* is unspecified, then debug info is not emitted for assembly sources (it is still emitted for C sources). This will be re-enabled for newer DWARF versions in a follow up patch. Enables defconfig+CONFIG_DEBUG_INFO to build cleanly with LLVM=1 LLVM_IAS=1 for x86_64 and arm64. Cc: <stable@vger.kernel.org> Link: ClangBuiltLinux/linux#716 Reported-by: Dmitry Golovin <dima@golovin.in> Reported-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Dmitry Golovin <dima@golovin.in> Suggested-by: Nathan Chancellor <natechancellor@gmail.com> Suggested-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> [nd: backport to avoid conflicts from: commit 10e68b02c861 ("Makefile: support compressed debug info") commit 7b16994437c7 ("Makefile: Improve compressed debug info support detection") commit 695afd3d7d58 ("kbuild: Simplify DEBUG_INFO Kconfig handling")] Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Change-Id: Ia4da22fe1254ea433d4d346fc24158d66663c11a

tpimh added [BUG] Untriaged Something isn't working [TOOL] integrated-as The issue is relevant to LLVM integrated assembler [ARCH] arm64 This bug impacts ARCH=arm64 labels Sep 27, 2019

tpimh mentioned this issue Mar 5, 2020

s390: DWARF2 only supports one section per compilation unit #919

Closed

nickdesaulniers removed the [ARCH] arm64 This bug impacts ARCH=arm64 label Mar 19, 2020

nickdesaulniers changed the title ~~ARM64: DWARF2 only supports one section per compilation unit~~ DWARF2 only supports one section per compilation unit Mar 19, 2020

This was referenced Mar 24, 2020

DWARF2 warning in arch/mips/vdso/elf.S #607

Closed

LLD + ThinLTO fails with "SHF_MERGE section size must be a multiple of sh_entsize" #510

Closed

tpimh mentioned this issue May 10, 2020

Enable integrated-as on selected arches on linux-next ClangBuiltLinux/continuous-integration#274

Merged

nickdesaulniers added [BUG] linux A bug that should be fixed in the mainline kernel. [PATCH] Submitted A patch has been submitted for review and removed [BUG] Untriaged Something isn't working labels Nov 4, 2020

nickdesaulniers self-assigned this Nov 4, 2020

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DWARF2 only supports one section per compilation unit #716

DWARF2 only supports one section per compilation unit #716

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DWARF2 only supports one section per compilation unit #716

DWARF2 only supports one section per compilation unit #716

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