From: Fangrui Song i@maskray.me
[ Upstream commit e0eb1b6b0cd29ca7793c501d5960fd36ba11f110 ]
.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@kernel.org Closes: https://github.com/ClangBuiltLinux/linux/issues/2093 Signed-off-by: Fangrui Song i@maskray.me Tested-by: Nathan Chancellor nathan@kernel.org Link: https://lore.kernel.org/r/20250602-riscv-vdso-v1-1-0620cf63cff0@maskray.me Signed-off-by: Palmer Dabbelt palmer@dabbelt.com Signed-off-by: Sasha Levin sashal@kernel.org ---
**YES**
This commit should be backported to stable kernel trees for the following reasons:
1. **Regression Fix**: The commit explicitly fixes a regression introduced by commit 8f8c1ff879fab60f80f3a7aec3000f47e5b03ba9 ("riscv: vdso.lds.S: remove hardcoded 0x800 .text start addr"). Regression fixes are high-priority candidates for stable backporting.
2. **Fixes Invalid ELF Structure**: The issue is not merely cosmetic. The PT_DYNAMIC segment is reported as "invalid" by llvm-readelf, indicating the ELF structure is technically incorrect. From the linker script: ``` .dynamic : { *(.dynamic) } :text :dynamic .rodata : { ... } // implicitly inherits :dynamic from previous section ``` Without the explicit `:text` specification, `.rodata` inherits the segment attributes from the preceding `.dynamic` section, incorrectly including it in the PT_DYNAMIC segment.
3. **Minimal and Safe Change**: The fix is a single-line change that adds `:text` to the `.rodata` section definition: ```diff - } + } :text ``` This explicitly places `.rodata` in the text segment only, excluding it from PT_DYNAMIC. The change has no functional impact beyond correcting the ELF structure.
4. **Similar to Previous Backported Commits**: This is similar to commit #2 in the reference list ("riscv: vdso: fix section overlapping under some conditions") which was marked YES for backporting. Both commits fix structural issues in the vDSO linker script that cause build/tooling errors.
5. **Potential for Broader Impact**: While the immediate symptom is a warning from llvm-readelf, an invalid PT_DYNAMIC segment could potentially cause issues with: - Build systems that validate ELF structures - Runtime loaders with strict ELF validation - Debugging and analysis tools - Future toolchain versions that may be less tolerant of invalid structures
The commit meets the stable tree criteria: it fixes an important bug (invalid ELF structure), the fix is small and contained, and there's minimal risk of regression.
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 cbe2a179331d2..99e51f7755393 100644 --- a/arch/riscv/kernel/vdso/vdso.lds.S +++ b/arch/riscv/kernel/vdso/vdso.lds.S @@ -31,7 +31,7 @@ SECTIONS *(.data .data.* .gnu.linkonce.d.*) *(.dynbss) *(.bss .bss.* .gnu.linkonce.b.*) - } + } :text
.note : { *(.note.*) } :text :note