Re: [PATCH] powerpc/vmlinux.lds: Drop .interp description

[Madhavan Srinivasan <maddy@linux.ibm.com>]

Will pick it up. Thanks

Maddy

On 10/27/25 1:16 PM, Vishal Chourasia wrote:
> ping.
>
> what's the status for this patch?
>
> vishalc
>
>
> On Tue, Oct 21, 2025 at 01:48:31PM +0530, Vishal Chourasia wrote:
>> On Sat, Oct 18, 2025 at 06:52:40PM +0100, Nathan Chancellor wrote:
>>> Commit da30705c4621 ("arch/powerpc: Remove .interp section in vmlinux")
>>> intended to drop the .interp section from vmlinux but even with this
>>> change, relocatable kernels linked with ld.lld contain an empty .interp
>>> section, which ends up causing crashes in GDB [1].
>>>
>>>    $ make -skj"$(nproc)" ARCH=powerpc LLVM=1 clean pseries_le_defconfig vmlinux
>>>
>>>    $ llvm-readelf -S vmlinux | grep interp
>>>      [44] .interp           PROGBITS        c0000000021ddb34 21edb34 000000 00   A  0   0  1
>>>
>>> There appears to be a subtle difference between GNU ld and ld.lld when
>>> it comes to discarding sections that specify load addresses [2].
>>>
>>> Since '--no-dynamic-linker' prevents emission of the .interp section,
>>> there is no need to describe it in the output sections of the vmlinux
>>> linker script. Drop the .interp section description from vmlinux.lds.S
>>> to avoid this issue altogether.
>>>
>>> Link: https://sourceware.org/bugzilla/show_bug.cgi?id=33481 [1]
>>> Link: https://github.com/ClangBuiltLinux/linux/issues/2137 [2]
>>> Reported-by: Vishal Chourasia <vishalc@linux.ibm.com>
>>> Closes: https://lore.kernel.org/20251013040148.560439-1-vishalc@linux.ibm.com/
>>> Signed-off-by: Nathan Chancellor <nathan@kernel.org>
>>> ---
>>>   arch/powerpc/kernel/vmlinux.lds.S | 1 -
>>>   1 file changed, 1 deletion(-)
>>>
>>> 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 = .;
>>>
>>> ---
>>> base-commit: 3a8660878839faadb4f1a6dd72c3179c1df56787
>>> change-id: 20251018-ppc-fix-lld-interp-1a78c361cd42
>>>
>> With this patch, I don't see .interp section being emitted the final
>> vmlinux binary.
>>
>> ```
>> (i) ❯ make LLVM=1 vmlinux
>> (i) ❯ llvm-readelf -p .comment vmlinux
>>
>> String dump of section '.comment':
>> [     1] clang version 22.0.0git (https://github.com/llvm/llvm-project.git 7314565281ec28b745502c3f429fd431e16673eb)
>> [    6d] Linker: LLD 22.0.0 (https://github.com/llvm/llvm-project.git 7314565281ec28b745502c3f429fd431e16673eb)
>>
>> (i) ❯ llvm-readelf -p .interp vmlinux
>> llvm-readelf: warning: 'vmlinux': could not find section '.interp'
>> ```
>>
>> Tested-by: Vishal Chourasia <vishalc@linux.ibm.com>