From: Stephen Hemminger <stephen@networkplumber.org>
To: dev@dpdk.org
Cc: Stephen Hemminger <stephen@networkplumber.org>
Subject: [PATCH v3 0/6] fix GCC warnings when building with LTO
Date: Thu, 15 Jan 2026 22:46:21 -0800 [thread overview]
Message-ID: <20260116064646.224254-1-stephen@networkplumber.org> (raw)
In-Reply-To: <20251023194237.197681-1-stephen@networkplumber.org>
This series fixes all warnings produced by GCC when building DPDK with
Link Time Optimization (LTO) enabled. LTO performs aggressive cross-
compilation-unit inlining and interprocedural analysis, which exposes
issues that are not visible during normal compilation.
The problems were diagnosed using AI but the fixes all look
very reasonable and consistent with other code.
The fixes fall into three categories:
1. Buffer sizing for static analysis (patches 1, 6)
When LTO inlines functions across compilation units, GCC's static
analyzer gains visibility into buffer sizes and all code paths.
This causes warnings when the analyzer cannot prove that runtime-
selected code paths stay within buffer bounds. The fixes provide
either larger buffers or explicit bounds checks to satisfy the
analyzer.
2. Variable Length Array (VLA) elimination (patches 2, 3, 4)
VLAs cause -Wvla-larger-than warnings with LTO because the compiler
cannot determine array bounds at compile time. These patches replace
VLAs with fixed-size arrays using existing defines, then remove the
warning suppression flag that was masking the issue.
3. Genuine bug fix (patch 5)
The LTO analysis uncovered an actual buffer overflow bug where a
1-byte allocation was being used for an 808-byte structure. This
is a real memory corruption issue, not just a false positive.
The patches have been tested with GCC 14 using -flto=auto and produce
a clean build with no warnings.
v3 - add all the other stuff necessary to fix all the LTO warnings
Stephen Hemminger (6):
test/soring: fix buffer overflow warnings with LTO
common/cnxk: replace variable length state array
common/cnxk: replace variable length array
common/cnxk: re-enable vla warnings
common/cnxk: fix buffer overflow in reassembly SA setup
net/mlx5/hws: fix LTO false positive stringop-overflow warning
app/test/test_soring.c | 29 +++++++++++++++++++++-------
drivers/common/cnxk/meson.build | 2 --
drivers/common/cnxk/roc_aes.c | 3 ++-
drivers/common/cnxk/roc_nix_inl.c | 2 +-
drivers/common/cnxk/roc_platform.c | 4 ++--
drivers/net/mlx5/hws/mlx5dr_action.c | 14 ++++++++++++++
6 files changed, 41 insertions(+), 13 deletions(-)
--
2.51.0
next prev parent reply other threads:[~2026-01-16 6:46 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-23 19:41 [RFC 0/3] common/cnxk: remove dependence on VLA Stephen Hemminger
2025-10-23 19:41 ` [RFC 1/3] common/cnxk: replace variable length state array Stephen Hemminger
2025-10-23 19:41 ` [RFC 2/3] common/cnxk: replace variable length array Stephen Hemminger
2025-10-27 5:22 ` [EXTERNAL] " Harman Kalra
2025-10-23 19:41 ` [RFC 3/3] common/cnxk: re-enable vla warnings Stephen Hemminger
2026-01-14 1:49 ` [PATCH v2 0/3] common/cnxk: remove variable length arrays Stephen Hemminger
2026-01-14 1:49 ` [PATCH v2 1/3] common/cnxk: replace variable length state array Stephen Hemminger
2026-01-14 1:50 ` [PATCH v2 2/3] common/cnxk: replace variable length array Stephen Hemminger
2026-01-14 1:50 ` [PATCH v2 3/3] common/cnxk: re-enable vla warnings Stephen Hemminger
2026-01-16 6:46 ` Stephen Hemminger [this message]
2026-01-16 6:46 ` [PATCH v3 1/6] test/soring: fix buffer overflow warnings with LTO Stephen Hemminger
2026-01-16 9:32 ` Morten Brørup
2026-01-19 22:48 ` Stephen Hemminger
2026-01-20 8:49 ` Morten Brørup
2026-01-20 14:34 ` Stephen Hemminger
2026-01-20 15:01 ` Morten Brørup
2026-01-20 15:40 ` Konstantin Ananyev
2026-01-20 15:48 ` Stephen Hemminger
2026-01-20 16:52 ` Stephen Hemminger
2026-01-20 19:27 ` Stephen Hemminger
2026-01-21 10:40 ` Morten Brørup
2026-01-21 12:56 ` Konstantin Ananyev
2026-01-21 14:57 ` Stephen Hemminger
2026-01-16 6:46 ` [PATCH v3 2/6] common/cnxk: replace variable length state array Stephen Hemminger
2026-01-16 6:46 ` [PATCH v3 3/6] common/cnxk: replace variable length array Stephen Hemminger
2026-01-16 6:46 ` [PATCH v3 4/6] common/cnxk: re-enable vla warnings Stephen Hemminger
2026-01-16 6:46 ` [PATCH v3 5/6] common/cnxk: fix buffer overflow in reassembly SA setup Stephen Hemminger
2026-01-16 6:46 ` [PATCH v3 6/6] net/mlx5/hws: fix LTO false positive stringop-overflow warning Stephen Hemminger
2026-01-19 22:44 ` [PATCH v4 0/6] fix build failures with LTO enabled Stephen Hemminger
2026-01-19 22:44 ` [PATCH v4 1/6] common/cnxk: replace variable length state array Stephen Hemminger
2026-01-19 22:44 ` [PATCH v4 2/6] common/cnxk: replace variable length array Stephen Hemminger
2026-01-19 22:44 ` [PATCH v4 3/6] common/cnxk: re-enable vla warnings Stephen Hemminger
2026-01-19 22:44 ` [PATCH v4 4/6] common/cnxk: fix buffer overflow in reassembly SA setup Stephen Hemminger
2026-01-19 22:44 ` [PATCH v4 5/6] net/mlx5: fix LTO false positive stringop-overflow warning Stephen Hemminger
2026-01-19 22:44 ` [PATCH v4 6/6] test/soring: fix stringop-overflow warning with LTO Stephen Hemminger
2026-01-20 19:52 ` [PATCH 0/6] Fix LTO compilation warnings Stephen Hemminger
2026-01-20 19:52 ` [PATCH v5 1/6] common/cnxk: replace variable length state array Stephen Hemminger
2026-01-20 19:52 ` [PATCH v5 2/6] common/cnxk: replace variable length array Stephen Hemminger
2026-01-20 19:52 ` [PATCH v5 3/6] common/cnxk: re-enable vla warnings Stephen Hemminger
2026-01-20 19:52 ` [PATCH v5 4/6] common/cnxk: fix buffer overflow in SA setup Stephen Hemminger
2026-01-20 19:52 ` [PATCH v5 5/6] net/mlx5: fix LTO stringop-overflow warning Stephen Hemminger
2026-02-05 13:43 ` Dariusz Sosnowski
2026-02-05 17:07 ` Stephen Hemminger
2026-01-20 19:52 ` [PATCH v5 6/6] ring: use inline instead of always inline in soring Stephen Hemminger
2026-01-22 9:52 ` Konstantin Ananyev
2026-01-22 10:49 ` Morten Brørup
2026-02-05 17:55 ` [PATCH v6 0/6] Fix LTO compilation warnings Stephen Hemminger
2026-02-05 17:55 ` [PATCH v6 1/6] common/cnxk: replace variable length state array Stephen Hemminger
2026-03-02 19:06 ` [EXTERNAL] " Tejasree Kondoj
2026-03-02 19:36 ` Stephen Hemminger
2026-02-05 17:55 ` [PATCH v6 2/6] common/cnxk: replace variable length array Stephen Hemminger
2026-03-02 10:51 ` [EXTERNAL] " Tejasree Kondoj
2026-02-05 17:55 ` [PATCH v6 3/6] common/cnxk: re-enable vla warnings Stephen Hemminger
2026-03-02 16:50 ` Nithin Dabilpuram
2026-02-05 17:55 ` [PATCH v6 4/6] common/cnxk: fix buffer overflow in SA setup Stephen Hemminger
2026-03-02 16:40 ` Nithin Dabilpuram
2026-02-05 17:55 ` [PATCH v6 5/6] ring: use inline instead of always inline in soring Stephen Hemminger
2026-02-05 17:55 ` [PATCH v6 6/6] net/mlx5: fix LTO stringop-overflow warning Stephen Hemminger
2026-02-06 9:51 ` Dariusz Sosnowski
2026-02-27 7:57 ` [PATCH v6 0/6] Fix LTO compilation warnings David Marchand
2026-03-03 16:24 ` David Marchand
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