Re: [PATCH 47/58] objtool/klp: Add test for symbols with no checksum entry of their own

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The test incorrectly checks for duplicate target addresses in `.discard.sym_checksum` by searching for duplicate relocation offsets (`$1`), causing the duplicate check to always silently pass.
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commit 1616f973328c423b8bf16ffbd15bb9fb6ff8d48a
Author: Song Liu <song@kernel.org>

objtool/klp: Add test for symbols with no checksum entry of their own

This commit adds a test to ensure that symbols without their own checksum
entries, like zero-length symbols or aliases, do not erroneously create
duplicate entries in .discard.sym_checksum.

> diff --git a/tools/objtool/tests/generic/test-checksum-skip.sh b/tools/objtool/tests/generic/test-checksum-skip.sh
> new file mode 100755
> index 0000000000000..a4ce1889db8f0
> --- /dev/null
> +++ b/tools/objtool/tests/generic/test-checksum-skip.sh

[ ... ]

> +# One entry per address, which is what the skipping is for.
> +dupes="$(in_relocs orig.o | awk '/rela\.discard\.sym_checksum/,/^$/ {
> +		if ($1 ~ /^[0-9a-f]{8,}/) print $1
> +	 }' | sort | uniq -d)"
> +[ -z "$dupes" ] ||
> +	fail "two checksum entries for one address: $dupes"

[Severity: Medium]
Does this logic actually verify the "one entry per address" invariant?

By extracting $1 (the relocation offset) instead of the target symbol or
address, it appears this code only checks for duplicate offsets within the
section.

Since relocation offsets are inherently unique within a section, does this
mean the duplicate check will silently pass even if multiple checksum entries
point to the exact same address?

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Sashiko AI review · https://sashiko.dev/#/patchset/20260911185031.1534046-1-song@kernel.org?part=47