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

[Ian Rogers <irogers@google.com>]

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.

[1] https://lore.kernel.org/linux-perf-users/20260520190538.142018-32-irogers@google.com/

Ian Rogers (3):
  perf build: Unconditionally set up libunwind feature build flags
  perf kwork: Fix address sanitizer issues
  perf kwork: Fix memory management of kwork_work

 tools/perf/Makefile.config  | 103 ++++++++++++------------
 tools/perf/builtin-kwork.c  | 151 ++++++++++++++++++++++++++++--------
 tools/perf/util/bpf_kwork.c |  14 +++-
 tools/perf/util/kwork.h     |   9 +++
 4 files changed, 188 insertions(+), 89 deletions(-)

-- 
2.54.0.746.g67dd491aae-goog