valgrind memcheck 是否支持检查 mmap答案

【问题标题】：Does valgrind memcheck support checking mmapvalgrind memcheck 是否支持检查 mmap
【发布时间】：2013-02-26 08:53:02
【问题描述】：

我正在尝试使用 valgrind 来检测内存泄漏。它适用于堆泄漏（即来自 malloc 或 new 的内存分配）。但是，它是否支持在 linux 中检查 mmap 泄漏？

谢谢张

【问题讨论】：

标签： c++ c memory-leaks valgrind mmap

【解决方案1】：

遗憾的是，valgrind 的 memcheck 不支持 mmap 跟踪（至少不是开箱即用的），但还是有希望的。

我最近遇到了 valgrind-mmt，这是一个用于跟踪 mmap 内存访问和分配的 valgrind 分支： https://nouveau.freedesktop.org/wiki/Valgrind-mmt

它由envytools开发，似乎主要用于图形驱动开发。

mmap 跟踪工具mmt 对所有对 mmap 内存的访问进行深度跟踪，包括加载和存储。这对于查找泄漏的 mmap 内存的工作来说可能太多了，并且需要对工具的输出进行处理和分析，但是通过一些仔细的工作，它可能对检测 mmap 泄漏情况很有用。就个人而言，我使用它只取得了部分成功，但也许其他人会更幸运。

请注意，它可能不适合anonymous mmap allocations。

入门：

克隆并构建envytools/envytools repository
克隆并构建envytools/valgrind repository
使用以下参数运行 valgrind：

/usr/local/bin/valgrind --tool=mmt --mmt-trace-file=[mmapped-file-to-be-traced] --log-file=mmt-log.bin
解码 mmt 输出：demmt -l mmt-log.bin > mmt-log.txt

【讨论】：

【解决方案2】：

不能直接调试，很难调试，看valgrind.h

   VALGRIND_MALLOCLIKE_BLOCK should be put immediately after the point where a
   heap block -- that will be used by the client program -- is allocated.
   It's best to put it at the outermost level of the allocator if possible;
   for example, if you have a function my_alloc() which calls
   internal_alloc(), and the client request is put inside internal_alloc(),
   stack traces relating to the heap block will contain entries for both
   my_alloc() and internal_alloc(), which is probably not what you want.

   For Memcheck users: if you use VALGRIND_MALLOCLIKE_BLOCK to carve out
   custom blocks from within a heap block, B, that has been allocated with
   malloc/calloc/new/etc, then block B will be *ignored* during leak-checking
   -- the custom blocks will take precedence.

   VALGRIND_FREELIKE_BLOCK is the partner to VALGRIND_MALLOCLIKE_BLOCK.  For
   Memcheck, it does two things:

   - It records that the block has been deallocated.  This assumes that the
     block was annotated as having been allocated via
     VALGRIND_MALLOCLIKE_BLOCK.  Otherwise, an error will be issued.

   - It marks the block as being unaddressable.

   VALGRIND_FREELIKE_BLOCK should be put immediately after the point where a
   heap block is deallocated.

【讨论】：