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comparison xml/en/docs/dev/development_guide.xml @ 2611:454af1d39021
Development guide: Debugging memory issues section.
| author | Roman Arutyunyan <arut@nginx.com> |
|---|---|
| date | Fri, 16 Oct 2020 17:55:16 +0100 |
| parents | c6c259d3601a |
| children | 5e3591372bf6 |
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| 2610:fdfe54a01ea1 | 2611:454af1d39021 |
|---|---|
| 7264 </programlisting> | 7264 </programlisting> |
| 7265 </para> | 7265 </para> |
| 7266 </section> | 7266 </section> |
| 7267 </section> | 7267 </section> |
| 7268 | 7268 |
| 7269 <section name="Debugging memory issues" id="debug_memory"> | |
| 7270 | |
| 7271 <para> | |
| 7272 To debug memory issues such as buffer overruns or use-after-free errors, you | |
| 7273 can use the <link url="https://en.wikipedia.org/wiki/AddressSanitizer"> | |
| 7274 AddressSanitizer</link> (ASan) supported by some modern compilers. | |
| 7275 To enable ASan with <literal>gcc</literal> and <literal>clang</literal>, | |
| 7276 use the <literal>-fsanitize=address</literal> compiler and linker option. | |
| 7277 When building nginx, this can be done by adding the option to | |
| 7278 <literal>--with-cc-opt</literal> and <literal>--with-ld-opt</literal> | |
| 7279 parameters of the <literal>configure</literal> script. | |
| 7280 </para> | |
| 7281 | |
| 7282 <para> | |
| 7283 Since most allocations in nginx are made from nginx internal | |
| 7284 <link id="pool">pool</link>, enabling ASan may not always be enough to debug | |
| 7285 memory issues. | |
| 7286 The internal pool allocates a big chunk of memory from the system and cuts | |
| 7287 smaller allocations from it. | |
| 7288 However, this mechanism can be disabled by setting the | |
| 7289 <literal>NGX_DEBUG_PALLOC</literal> macro to <literal>1</literal>. | |
| 7290 In this case, allocations are passed directly to the system allocator giving it | |
| 7291 full control over the buffers boundaries. | |
| 7292 </para> | |
| 7293 | |
| 7294 <para> | |
| 7295 The following configuration line summarizes the information provided above. | |
| 7296 It is recommended while developing third-party modules and testing nginx on | |
| 7297 different platforms. | |
| 7298 </para> | |
| 7299 | |
| 7300 <programlisting> | |
| 7301 auto/configure --with-cc-opt='-fsanitize=address -DNGX_DEBUG_PALLOC=1' | |
| 7302 --with-ld-opt=-fsanitize=address | |
| 7303 </programlisting> | |
| 7304 | |
| 7305 </section> | |
| 7306 | |
| 7269 <section name="Common Pitfalls" id="common_pitfals"> | 7307 <section name="Common Pitfalls" id="common_pitfals"> |
| 7270 | 7308 |
| 7271 <section name="Writing a C module" id="module_pitfall"> | 7309 <section name="Writing a C module" id="module_pitfall"> |
| 7272 | 7310 |
| 7273 <para> | 7311 <para> |