Re: [PATCH v1 0/3] perf: Fix kwork memory sanitization and libunwind test builds

[Arnaldo Carvalho de Melo <acme@kernel.org>]

On Fri, May 22, 2026 at 02:33:05PM -0700, Ian Rogers wrote:
> On Thu, May 21, 2026 at 12:24 AM Ian Rogers <irogers@google.com> wrote:
> >
> > The combination of the libunwind refactoring and build system changes
> > exposed a build-test regression for the libunwind build using a cached
> > feature dump. Re-send kwork fixes [1] moving a definition to kwork.h
> > to avoid breaking no libbpf builds.
> >
> > 1. Build Fix for libunwind:
> >    "make feature-dump" runs without LIBUNWIND=1, skipping the setup of
> >    libunwind LDFLAGS. When Makefile.feature is included to generate the
> >    cached FEATURE-DUMP, the local test-libunwind.bin compiles without
> >    arch-specific link flags (-lunwind-x86_64) and fails, caching a false
> >    negative ("feature-libunwind=0"). Later builds (such as make_libunwind_O
> >    reusing the dump) compile the unwinder based on CONFIG_LIBUNWIND (remote)
> >    but disable HAVE_LIBUNWIND_SUPPORT (local), breaking compilation due to
> >    missing maps__e_machine declarations in maps.h. Fixed by unconditionally
> >    setting up libunwind feature build flags in Makefile.config.
> >
> > 2. kwork ASAN Double-Free & Leaks:
> >    - Solves double-free in the record command argument array due to
> >      parse_options mutation, by preserving original pointers in a calloc'ed
> >      to_free buffer.
> >    - Ensures kwork_usage string is freed on all exit paths.
> >
> > 3. kwork Unified Memory Lifecycle:
> >    - Establishes a unified memory ownership model for kwork_work by
> >      ensuring work names are dynamically duplicated via strdup() and
> >      consistently freed using work_exit() and a central perf_kwork__exit()
> >      teardown path.
> 
> It would be nice to land these fixes. Thomas reported the kwork crashes in:
> https://lore.kernel.org/linux-perf-users/314df838-4c38-4f03-9515-ae1dabd09a54@linux.ibm.com/

Thanks, applied to perf-tools-next, for v7.2.

- Arnaldo