Re: [PATCH] perf llvm: Clean up after a failed disassembly

[Ian Rogers]

On Tue, Mar 3, 2026 at 3:00 PM Peter Collingbourne <pcc@xxxxxxxxxx> wrote:
>
> An error returned from a failed backend will cause perf to call the next
> backend. If the error happens mid-function, e.g. due to an unrecognized
> instruction, we will end up with duplicated instructions in the output
> unless the backend that failed deletes any instructions that it created
> before failing. The capstone backend was already doing this but the LLVM
> backend was not; fix it.
>
> Link: https://linux-review.googlesource.com/id/I377eef3cd662ab98fbcd69e5004a259fa3d7aa06
> Signed-off-by: Peter Collingbourne <pcc@xxxxxxxxxx>

Reviewed-by: Ian Rogers <irogers@xxxxxxxxxx>

Thanks,
Ian

> ---
>  tools/perf/util/llvm.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/tools/perf/util/llvm.c b/tools/perf/util/llvm.c
> index 0d126d233c019..87fceae8488a7 100644
> --- a/tools/perf/util/llvm.c
> +++ b/tools/perf/util/llvm.c
> @@ -261,6 +261,15 @@ int symbol__disassemble_llvm(const char *filename, struct symbol *sym,
>         ret = 0;
>
>  err:
> +       if (ret != 0) {
> +               struct disasm_line *tmp;
> +
> +               list_for_each_entry_safe(dl, tmp, &notes->src->source,
> +                                        al.node) {
> +                       list_del(&dl->al.node);
> +                       disasm_line__free(dl);
> +               }
> +       }
>         LLVMDisasmDispose(disasm);
>         free(code_buf);
>         free(line_storage);
> --
> 2.53.0.473.g4a7958ca14-goog
>