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

[Namhyung Kim]

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@xxxxxxxxxx/
> 
> v3:
>  - Minor formatting fixes.
> https://lore.kernel.org/linux-perf-users/20260503003552.1063540-1-irogers@xxxxxxxxxx/
> 
> v2:
> https://lore.kernel.org/lkml/20260502155656.478642-1-irogers@xxxxxxxxxx/
> 
> v1:
> https://lore.kernel.org/linux-perf-users/20260502064839.282422-1-irogers@xxxxxxxxxx/
> 
> 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
>