[PATCH] riscv: vdso: Exclude .rodata from the PT_DYNAMIC segment

[Palmer Dabbelt]

On Tue, 03 Jun 2025 14:52:18 PDT (-0700), nathan at kernel.org wrote:
> On Mon, Jun 02, 2025 at 08:48:44PM -0700, Fangrui Song wrote:
>> .rodata is implicitly included in the PT_DYNAMIC segment due to
>> inheriting the segment of the preceding .dynamic section (in both GNU ld
>> and LLD).  When the .rodata section's size is not a multiple of 16
>> bytes on riscv64, llvm-readelf will report a "PT_DYNAMIC dynamic table
>> is invalid" warning.  Note: in the presence of the .dynamic section, GNU
>> readelf and llvm-readelf's -d option decodes the dynamic section using
>> the section.
>>
>> This issue arose after commit 8f8c1ff879fab60f80f3a7aec3000f47e5b03ba9
>> ("riscv: vdso.lds.S: remove hardcoded 0x800 .text start addr"), which
>> placed .rodata directly after .dynamic by removing .eh_frame.
>>
>> This patch resolves the implicit inclusion into PT_DYNAMIC by explicitly
>> specifying the :text output section phdr.
>>
>> Reported-by: Nathan Chancellor <nathan at kernel.org>
>> Closes: https://github.com/ClangBuiltLinux/linux/issues/2093
>> Signed-off-by: Fangrui Song <i at maskray.me>
>
> Tested-by: Nathan Chancellor <nathan at kernel.org>

Thanks, I'll pick it up (might take a bit to show up on fixes, I'm 
trying to sort out another amdgpu stack warning...)

>
>> ---
>>  arch/riscv/kernel/vdso/vdso.lds.S | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/arch/riscv/kernel/vdso/vdso.lds.S b/arch/riscv/kernel/vdso/vdso.lds.S
>> index abc69cda0445b1f500a89b47deefa31349103f08..62e0410f69f09e2bbf27101c000d604193f525cb 100644
>> --- a/arch/riscv/kernel/vdso/vdso.lds.S
>> +++ b/arch/riscv/kernel/vdso/vdso.lds.S
>> @@ -30,7 +30,7 @@ SECTIONS
>>  		*(.data .data.* .gnu.linkonce.d.*)
>>  		*(.dynbss)
>>  		*(.bss .bss.* .gnu.linkonce.b.*)
>> -	}
>> +	}						:text
>>
>>  	.note		: { *(.note.*) }		:text	:note
>>
>>
>> ---
>> base-commit: 1a3f6980889df3fc90ad3e4a525061d2c138adba
>> change-id: 20250602-riscv-vdso-13efdee34a24
>>
>> Best regards,
>> --
>> Fangrui Song <i at maskray.me>
>>