* Re: [PATCH] arch/powerpc: Remove .interp section in vmlinux
[not found] ` <20251013040148.560439-1-vishalc@linux.ibm.com>
@ 2025-10-13 6:46 ` Christophe Leroy
2025-10-13 7:27 ` Vishal Chourasia
0 siblings, 1 reply; 6+ messages in thread
From: Christophe Leroy @ 2025-10-13 6:46 UTC (permalink / raw)
To: Vishal Chourasia, christophe.leroy, maddy, linuxppc-dev,
linux-kernel, clang-built-linux, llvm@lists.linux.dev,
Nathan Chancellor
+CLANG ppl
Hi,
Le 13/10/2025 à 06:01, Vishal Chourasia a écrit :
> While debugging a ppc64le QEMU guest on an x86_64 host, I observed GDB crashes
> when attempting to attach to the remote target:
>
> (gdb) target remote :1234
>
> Investigation revealed that cross-compiling the Linux kernel for ppc64le on an
> x86_64 host using Clang produces a vmlinux binary containing an empty .interp
> section. This empty .interp section is responsible for the GDB crashes.
Which version of CLANG is it ?
>
> This issue does not occur when:
> - Building for ppc64le target using GCC on x86_64 host
> - Building for ppc64le target using Clang on ppc64le host
Is it the same CLANG version ?
> - Building for ppc64le target using GCC on ppc64le host
>
> For details refer [1]
>
> [1] https://sourceware.org/bugzilla/show_bug.cgi?id=33481
Christophe
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] arch/powerpc: Remove .interp section in vmlinux
2025-10-13 6:46 ` [PATCH] arch/powerpc: Remove .interp section in vmlinux Christophe Leroy
@ 2025-10-13 7:27 ` Vishal Chourasia
2025-10-15 0:21 ` Nathan Chancellor
0 siblings, 1 reply; 6+ messages in thread
From: Vishal Chourasia @ 2025-10-13 7:27 UTC (permalink / raw)
To: Christophe Leroy
Cc: maddy, linuxppc-dev, linux-kernel, clang-built-linux,
llvm@lists.linux.dev, Nathan Chancellor
On Mon, Oct 13, 2025 at 08:46:48AM +0200, Christophe Leroy wrote:
> +CLANG ppl
>
> Hi,
>
> Le 13/10/2025 à 06:01, Vishal Chourasia a écrit :
> > While debugging a ppc64le QEMU guest on an x86_64 host, I observed GDB crashes
> > when attempting to attach to the remote target:
> >
> > (gdb) target remote :1234
> >
> > Investigation revealed that cross-compiling the Linux kernel for ppc64le on an
> > x86_64 host using Clang produces a vmlinux binary containing an empty .interp
> > section. This empty .interp section is responsible for the GDB crashes.
>
> Which version of CLANG is it ?
(i) ❯ clang --version
clang version 21.0.0git (https://github.com/llvm/llvm-project.git a80bccc6847be104948f46d313f03ac6b9ccb292)
>
> >
> > This issue does not occur when:
> > - Building for ppc64le target using GCC on x86_64 host
> > - Building for ppc64le target using Clang on ppc64le host
>
> Is it the same CLANG version ?
# clang --version
clang version 22.0.0git (https://github.com/llvm/llvm-project.git 2f755c543ab357bd83235592fcee37fa391cdd9d)
>
> > - Building for ppc64le target using GCC on ppc64le host
> >
> > For details refer [1]
> >
> > [1] https://sourceware.org/bugzilla/show_bug.cgi?id=33481
>
vishalc
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] arch/powerpc: Remove .interp section in vmlinux
2025-10-13 7:27 ` Vishal Chourasia
@ 2025-10-15 0:21 ` Nathan Chancellor
2025-10-15 3:37 ` Vishal Chourasia
0 siblings, 1 reply; 6+ messages in thread
From: Nathan Chancellor @ 2025-10-15 0:21 UTC (permalink / raw)
To: Vishal Chourasia
Cc: Christophe Leroy, maddy, linuxppc-dev, linux-kernel,
clang-built-linux, llvm@lists.linux.dev
Hi Vishal,
On Mon, Oct 13, 2025 at 12:57:00PM +0530, Vishal Chourasia wrote:
> On Mon, Oct 13, 2025 at 08:46:48AM +0200, Christophe Leroy wrote:
> > +CLANG ppl
> >
> > Hi,
> >
> > Le 13/10/2025 à 06:01, Vishal Chourasia a écrit :
> > > While debugging a ppc64le QEMU guest on an x86_64 host, I observed GDB crashes
> > > when attempting to attach to the remote target:
> > >
> > > (gdb) target remote :1234
> > >
> > > Investigation revealed that cross-compiling the Linux kernel for ppc64le on an
> > > x86_64 host using Clang produces a vmlinux binary containing an empty .interp
> > > section. This empty .interp section is responsible for the GDB crashes.
> >
> > Which version of CLANG is it ?
> (i) ❯ clang --version
> clang version 21.0.0git (https://github.com/llvm/llvm-project.git a80bccc6847be104948f46d313f03ac6b9ccb292)
>
> >
> > >
> > > This issue does not occur when:
> > > - Building for ppc64le target using GCC on x86_64 host
> > > - Building for ppc64le target using Clang on ppc64le host
> >
> > Is it the same CLANG version ?
> # clang --version
> clang version 22.0.0git (https://github.com/llvm/llvm-project.git 2f755c543ab357bd83235592fcee37fa391cdd9d)
>
> >
> > > - Building for ppc64le target using GCC on ppc64le host
> > >
> > > For details refer [1]
> > >
> > > [1] https://sourceware.org/bugzilla/show_bug.cgi?id=33481
In this bug report, you mention using LLVM=1. Does the issue happen if
you use GNU ld (ld.bfd) via LD (i.e., LD=powerpc64le-linux-gnu-ld or
equivalent) over ld.lld from LLVM=1? This sounds more likely to be a
linker difference rather than a compiler difference.
Cheers,
Nathan
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] arch/powerpc: Remove .interp section in vmlinux
2025-10-15 0:21 ` Nathan Chancellor
@ 2025-10-15 3:37 ` Vishal Chourasia
2025-10-15 18:27 ` Nathan Chancellor
0 siblings, 1 reply; 6+ messages in thread
From: Vishal Chourasia @ 2025-10-15 3:37 UTC (permalink / raw)
To: Nathan Chancellor
Cc: Christophe Leroy, maddy, linuxppc-dev, linux-kernel,
clang-built-linux, llvm@lists.linux.dev
Hello Nathan,
On Tue, Oct 14, 2025 at 05:21:54PM -0700, Nathan Chancellor wrote:
> In this bug report, you mention using LLVM=1. Does the issue happen if
> you use GNU ld (ld.bfd) via LD (i.e., LD=powerpc64le-linux-gnu-ld or
> equivalent) over ld.lld from LLVM=1? This sounds more likely to be a
> linker difference rather than a compiler difference.
Thank you for the insight.
Yes, when using powerpc64le-linux-gnu-ld linker .interp section is not
emitted.
Command:
$ make LLVM=1 ARCH=powerpc LD=powerpc64le-linux-gnu-ld -j 8 zImage
$ llvm-readelf -p .comment vmlinux
String dump of section '.comment':
[ 0] clang version 22.0.0git (https://github.com/llvm/llvm-project.git 7314565281ec28b745502c3f429fd431e16673eb)
$ llvm-readelf -p .interp vmlinux
llvm-readelf: warning: 'vmlinux': could not find section '.interp'
vishalc
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] arch/powerpc: Remove .interp section in vmlinux
2025-10-15 3:37 ` Vishal Chourasia
@ 2025-10-15 18:27 ` Nathan Chancellor
2025-10-16 6:06 ` Vishal Chourasia
0 siblings, 1 reply; 6+ messages in thread
From: Nathan Chancellor @ 2025-10-15 18:27 UTC (permalink / raw)
To: Vishal Chourasia
Cc: Christophe Leroy, maddy, linuxppc-dev, linux-kernel,
clang-built-linux, llvm@lists.linux.dev
On Wed, Oct 15, 2025 at 09:07:54AM +0530, Vishal Chourasia wrote:
> Hello Nathan,
>
> On Tue, Oct 14, 2025 at 05:21:54PM -0700, Nathan Chancellor wrote:
> > In this bug report, you mention using LLVM=1. Does the issue happen if
> > you use GNU ld (ld.bfd) via LD (i.e., LD=powerpc64le-linux-gnu-ld or
> > equivalent) over ld.lld from LLVM=1? This sounds more likely to be a
> > linker difference rather than a compiler difference.
>
> Thank you for the insight.
>
> Yes, when using powerpc64le-linux-gnu-ld linker .interp section is not
> emitted.
>
> Command:
> $ make LLVM=1 ARCH=powerpc LD=powerpc64le-linux-gnu-ld -j 8 zImage
> $ llvm-readelf -p .comment vmlinux
>
> String dump of section '.comment':
> [ 0] clang version 22.0.0git (https://github.com/llvm/llvm-project.git 7314565281ec28b745502c3f429fd431e16673eb)
>
> $ llvm-readelf -p .interp vmlinux
> llvm-readelf: warning: 'vmlinux': could not find section '.interp'
Thanks for confirming. Does this fix the issue for you? It appears to
work for me.
Cheers,
Nathan
diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
index de6ee7d35cff..15850296c0a9 100644
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -330,7 +330,6 @@ SECTIONS
}
.hash : AT(ADDR(.hash) - LOAD_OFFSET) { *(.hash) }
.gnu.hash : AT(ADDR(.gnu.hash) - LOAD_OFFSET) { *(.gnu.hash) }
- .interp : AT(ADDR(.interp) - LOAD_OFFSET) { *(.interp) }
.rela.dyn : AT(ADDR(.rela.dyn) - LOAD_OFFSET)
{
__rela_dyn_start = .;
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] arch/powerpc: Remove .interp section in vmlinux
2025-10-15 18:27 ` Nathan Chancellor
@ 2025-10-16 6:06 ` Vishal Chourasia
0 siblings, 0 replies; 6+ messages in thread
From: Vishal Chourasia @ 2025-10-16 6:06 UTC (permalink / raw)
To: Nathan Chancellor
Cc: Christophe Leroy, maddy, linuxppc-dev, linux-kernel,
clang-built-linux, llvm@lists.linux.dev
On 15/10/25 23:57, Nathan Chancellor wrote:
> On Wed, Oct 15, 2025 at 09:07:54AM +0530, Vishal Chourasia wrote:
>> Hello Nathan,
>>
>> On Tue, Oct 14, 2025 at 05:21:54PM -0700, Nathan Chancellor wrote:
>>> In this bug report, you mention using LLVM=1. Does the issue happen if
>>> you use GNU ld (ld.bfd) via LD (i.e., LD=powerpc64le-linux-gnu-ld or
>>> equivalent) over ld.lld from LLVM=1? This sounds more likely to be a
>>> linker difference rather than a compiler difference.
>> Thank you for the insight.
>>
>> Yes, when using powerpc64le-linux-gnu-ld linker .interp section is not
>> emitted.
>>
>> Command:
>> $ make LLVM=1 ARCH=powerpc LD=powerpc64le-linux-gnu-ld -j 8 zImage
>> $ llvm-readelf -p .comment vmlinux
>>
>> String dump of section '.comment':
>> [ 0] clang version 22.0.0git (https://github.com/llvm/llvm-project.git 7314565281ec28b745502c3f429fd431e16673eb)
>>
>> $ llvm-readelf -p .interp vmlinux
>> llvm-readelf: warning: 'vmlinux': could not find section '.interp'
> Thanks for confirming. Does this fix the issue for you? It appears to
> work for me.
>
> Cheers,
> Nathan
>
> diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
> index de6ee7d35cff..15850296c0a9 100644
> --- a/arch/powerpc/kernel/vmlinux.lds.S
> +++ b/arch/powerpc/kernel/vmlinux.lds.S
> @@ -330,7 +330,6 @@ SECTIONS
> }
> .hash : AT(ADDR(.hash) - LOAD_OFFSET) { *(.hash) }
> .gnu.hash : AT(ADDR(.gnu.hash) - LOAD_OFFSET) { *(.gnu.hash) }
> - .interp : AT(ADDR(.interp) - LOAD_OFFSET) { *(.interp) }
> .rela.dyn : AT(ADDR(.rela.dyn) - LOAD_OFFSET)
> {
> __rela_dyn_start = .;
Hello Nathan,
It does solve the problem, but with GNU linker it would work even
without this change.
regards,
vishalc
^ permalink raw reply [flat|nested] 6+ messages in thread
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[not found] ` <20251013040148.560439-1-vishalc@linux.ibm.com>
2025-10-13 6:46 ` [PATCH] arch/powerpc: Remove .interp section in vmlinux Christophe Leroy
2025-10-13 7:27 ` Vishal Chourasia
2025-10-15 0:21 ` Nathan Chancellor
2025-10-15 3:37 ` Vishal Chourasia
2025-10-15 18:27 ` Nathan Chancellor
2025-10-16 6:06 ` Vishal Chourasia
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