Re: [PATCH v5 0/9] [PATCH v5 0/9] perf DWARF: Fix libdw API contract violations and crashes

Namhyung Kim
2026-05-04T23:50:58Z

Hi Ian,

Just updated Masami's email address. Please use it for later.

Thanks,
Namhyung

On Mon, May 04, 2026 at 01:12:18AM -0700, Ian Rogers wrote:
> This patch series addresses a number of DWARF/libdw error-handling
> bugs and contract violations, preventing several real Userspace
> segmentation faults and memory/FD leaks.
>
> In v5, the series has been extensively restructured and polished based on
> comprehensive review feedback on v4, focusing on history granularity,
> bisectability, and defensive styling:
>
> - **Commit Splitting for Review Granularity**: Split the previously large
> libdw contract fix patch into 4 granular commits to cleanly isolate
> independent improvements: introducing clear_frames refactoring, fixing
> ORDER_CALLER parent update corruption, adding line 0 support, and
> consolidating core contract/leak cleanups.
>
> - **Bisectability & Correctness Hardening**:
> - Fixed an unused variable compilation failure (-Werror) in the split
> history to guarantee perfect git bisectability.
> - Fixed a line 0 fallback regression to ensure that if an optional call
> line is missing but the call file is valid, we fallback to line 0
> to preserve the filename rather than discarding the caller info entirely.
>
> - **Style & Robustness Polish**:
> - Standardized all newly introduced C++ style (//) comments to
> preferred C style (/* ... */) comments.
> - Implemented explicit safe string duplication style fix in annotate-data.
> - Corrected CU DIE propagation context inside probe-finder.
> - Enhanced the Patch 2 commit message to explicitly detail the removal
> of strict optional attribute aborts (decf) to clarify review queries.
>
> - **Tags Collected**: Integrated Acked-by tags from Namhyung Kim for Patch 1
> and Patch 9.
>
> v5:
> - Restructured series from 6 to 9 patches by splitting the libdw commit.
> - Fixed compilation bisectability and DWARF line 0 filename preservation regressions.
> - Standardized comment styles and applied safe duplication formatting fixes.
> - Updated commit messages with detailed optional attribute justifications.
>
> v4:
> - Localized and squashed robust error handling, memory/FD cleanup
> paths, and safe DWARF printing.
> https://lore.kernel.org/linux-perf-users/20260503171032.1559338-1-irogers@google.com/
>
> v3:
> - Minor formatting fixes.
> https://lore.kernel.org/linux-perf-users/20260503003552.1063540-1-irogers@google.com/
>
> v2:
> https://lore.kernel.org/lkml/20260502155656.478642-1-irogers@google.com/
>
> v1:
> https://lore.kernel.org/linux-perf-users/20260502064839.282422-1-irogers@google.com/
>
> Ian Rogers (9):
> perf dwarf-aux: Fix libdw segmentation fault in cu_walk_functions_at
> perf dwarf-aux: Fix libdw API contract violations
> perf srcline: Introduce inline_node__clear_frames()
> perf libdw: Fix callchain parent update in ORDER_CALLER mode
> perf libdw: Support DWARF line 0 in inline list
> perf libdw: Fix libdw API contract violations and memory leaks
> perf probe-finder: Fix libdw API contract violations
> perf annotate-data: Fix libdw API contract violations
> perf debuginfo: Fix libdw API contract violations
>
> tools/perf/util/annotate-data.c | 27 +++++----
> tools/perf/util/debuginfo.c | 9 ++-
> tools/perf/util/dwarf-aux.c | 39 ++++++------
> tools/perf/util/dwarf-aux.h | 5 ++
> tools/perf/util/libdw.c | 72 +++++++++++++++++-----
> tools/perf/util/probe-finder.c | 102 ++++++++++++++++++++------------
> tools/perf/util/srcline.c | 9 ++-
> tools/perf/util/srcline.h | 1 +
> 8 files changed, 179 insertions(+), 85 deletions(-)
>
> --
> 2.54.0.545.g6539524ca2-goog
>