On Fri, May 1, 2026 at 5:09 AM Josh Poimboeuf <[email protected]> wrote: > > Rewrite the symbol correlation code, using a tiered list of > deterministic strategies in a loop. For duplicately named symbols, each > tier applies a filter with the goal of finding a 1:1 deterministic > correlation between the original and patched version of the symbol. > > The three matching strategies are: > > find_twin(): A funnel of progressively tighter filters. Candidates > with the same demangled name are counted at four levels: name, scope > (local-vs-global), file (strict file association), and checksum > (unchanged functions). The widest level that yields a 1:1 match wins, > narrower levels are only tried when the wider level is ambiguous. > > find_twin_suffixed(): Uses already-correlated LLVM symbol pairs to map > .llvm.<hash> suffixes from orig to patched. Because all promoted > symbols from the same TU share the same hash, one correlated pair > seeds the mapping for the entire TU. > > find_twin_positional(): Last resort, matches symbols by position among > same-named candidates, similar to livepatch sympos. Used for data > objects like __quirk variables where no deterministic filter can > distinguish the candidates. > > Overall this works much better than the existing algorithm, particularly > with LTO kernels. > > Signed-off-by: Josh Poimboeuf <[email protected]>
Acked-by: Song Liu <[email protected]> Thanks for improving the correlation algorithm and adding detailed comments about all these scenarios!
