Re: [PATCH v2 19/58] objtool/klp: Add test for jump table key relocations

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] The jump label test fixture hardcodes a 64-bit PC-relative relocation which causes assembler errors on 32-bit architectures.
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commit 12aec6304341b6d166d36c18d507d8088ff90b91
Author: Puranjay Mohan <puranjay@kernel.org>

objtool/klp: Add test for jump table key relocations

A cloned __jump_table entry must keep a relocation in its key slot.
This patch adds tests and fixtures to ensure the relocation stays
properly populated for both exported and unexported vmlinux keys
during a klp diff.

> diff --git a/tools/objtool/tests/generic/fixtures/jump_label.c b/tools/objtool/tests/generic/fixtures/jump_label.c
> new file mode 100644
> index 0000000000000..ecd3c06912af5
> --- /dev/null
> +++ b/tools/objtool/tests/generic/fixtures/jump_label.c
> @@ -0,0 +1,76 @@

[ ... ]

> +int target(int x)
> +{
> +	int r = x;
> +
> +#if defined(NEW_KEY) && !defined(PATCHED)
> +	/* The original has no static branch at all. */
> +	return r + 1;
> +#else
> +	asm goto(
> +		"1:	nop\n\t"
> +		".pushsection	__jump_table, \"aw\"\n\t"
> +		".balign	8\n\t"
> +		"912:\n\t"
> +		".pushsection	.discard.annotate_data, \"M\", @progbits, 8\n\t"
> +		".long		912b - ., 1\n\t"
> +		".popsection\n\t"
> +		".long		1b - ., %l[l_yes] - .\n\t"
> +		".quad		%c0 - .\n\t"

[Severity: Low]
This inline assembly in target() explicitly requests a 64-bit PC-relative
relocation. On 32-bit x86 (which is supported by the test runner), the GNU
assembler cannot represent a 64-bit PC-relative relocation.

Will this cause the test fixture to fail to build when running objtool
tests in a 32-bit environment?

> +		".popsection\n\t"
> +		: : "i" (&KEY_NAME) : : l_yes);

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Sashiko AI review · https://sashiko.dev/#/patchset/20260914062514.926997-1-song@kernel.org?part=19