malloc（）和malloc_consolidate（）中的Segfaults [英] Segfaults in malloc() and malloc_consolidate()

问题描述

我的应用程序有时主要在malloc（）和malloc_consolidate（）中查看gdb中的回溯。

我验证了机器有足够的内存可用，甚至没有开始交换。
我检查了ulimits数据段和最大内存大小，都设置为unlimited。
我也运行在valgrind下的应用程序，没有发现任何内存错误。

现在我不知道还有什么可能导致这些segfaults。任何想法？

更新：
由于我没有找到任何与valgrind（或ptrcheck），可能是另一个应用程序正在破坏libc的内存结构，或者是每个进程都有一个单独的结构？

解决方案

另一种检查和防范使用malloc，realloc和free的bug是设置环境变量MALLOC_CHECK_，当设置MALLOC_CHECK_时，使用一个特殊的（效率较低的）实现，它被设计为容忍简单的错误，例如相同的参数或超出单个字节（一个错误），并不是所有这样的错误都可以被保护，但是，可能会导致内存泄漏。如果MALLOC_CHECK_设置为0，任何检测到的堆损坏将被默认忽略;如果设置为1，则在stderr上打印诊断;如果设置为2，则立即调用中止，这是有用的，因为否则可能会发生崩溃，并且真正的原因是很难跟踪。

http://www.gnu.org/s/libc/manual/html_node/Heap-Consistency-Checking.html#Heap-一致性检查

My application segfaults sometimes and mainly in malloc() and malloc_consolidate() when I look at the backtrace in gdb.

I verified that the machine has enough memory available, it didn't even start swapping. I checked ulimits for data segement and max memory size and both are set to 'unlimited'. I also ran the application under valgrind and didn't find any memory errors.

Now I'm out of ideas what else might be causing these segfaults. Any Ideas ?

Update: Since I'm not finding anything with valgrind (or ptrcheck), could it be that another application is trashing libc's memory structure or is there a separate structure for each process ?

解决方案

"Another possibility to check for and guard against bugs in the use of malloc, realloc and free is to set the environment variable MALLOC_CHECK_. When MALLOC_CHECK_ is set, a special (less efficient) implementation is used which is designed to be tolerant against simple errors, such as double calls of free with the same argument, or overruns of a single byte (off-by-one bugs). Not all such errors can be protected against, however, and memory leaks can result. If MALLOC_CHECK_ is set to 0, any detected heap corruption is silently ignored; if set to 1, a diagnostic is printed on stderr; if set to 2, abort is called immediately. This can be useful because otherwise a crash may happen much later, and the true cause for the problem is then very hard to track down."

http://www.gnu.org/s/libc/manual/html_node/Heap-Consistency-Checking.html#Heap-Consistency-Checking

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