Re: [RFC PATCH 0/2] Add cleanup_plugin for detecting problematic cleanup patterns

[Li Chen]

+Peter, Dan, and Bjorn

(My apologies for the oversight)

 ---- On Wed, 05 Nov 2025 16:46:55 +0800  Li Chen <me@linux.beauty> wrote --- 
 > From: Li Chen <chenl311@xxxxxxxxxxxxxxx>
 > 
 > Hello,
 > 
 > This patch series introduces a new GCC plugin called cleanup_plugin that
 > warns developers about problematic patterns when using variables with
 > __attribute__((cleanup(...))). The plugin addresses concerns documented
 > in include/linux/cleanup.h regarding resource leaks and interdependency
 > issues.
 > 
 > The cleanup attribute helpers (__free, DEFINE_FREE, etc.) are designed
 > to automatically clean up resources when variables go out of scope,
 > following LIFO (last in first out) ordering. However, certain patterns
 > can lead to subtle bugs:
 > 
 > 1. Uninitialized cleanup variables: Variables declared with cleanup
 >    attributes but not initialized can cause issues when cleanup functions
 >    are called on undefined values.
 > 
 > 2. NULL-initialized cleanup variables: The "__free(...) = NULL" pattern
 >    at function top can cause interdependency problems, especially when
 >    combined with guards or multiple cleanup variables, as the cleanup
 >    may run in unexpected contexts.
 > 
 > The plugin detects both of these problematic patterns and provides clear
 > warnings to developers, helping prevent  incorrect cleanup ordering.
 > Importantly, the plugin's warnings are not converted
 > to errors by -Werror, allowing builds to continue while still alerting
 > developers to potential issues.
 > 
 > The plugin is enabled by default as it provides valuable compile-time
 > feedback without impacting build performance.
 > 
 > Li Chen (2):
 >   gcc-plugins: add cleanup_plugin for uninitialized cleanup detection
 >   gcc-plugins: cleanup_plugin: detect NULL init
 > 
 >  scripts/Makefile.gcc-plugins         |   1 +
 >  scripts/gcc-plugins/Kconfig          |   6 +
 >  scripts/gcc-plugins/cleanup_plugin.c | 204 +++++++++++++++++++++++++++
 >  3 files changed, 211 insertions(+)
 >  create mode 100644 scripts/gcc-plugins/cleanup_plugin.c
 > 
 > -- 
 > 2.51.0
 > 
 > 
Regards,

Li​