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https://issues.apache.org/jira/browse/HDFS-10188?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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James Clampffer updated HDFS-10188:
-----------------------------------
Description:
I propose implementing a set of memory new/delete pairs with additional
checking to detect double deletes, read-after-delete, and write-after-deletes
to help debug resource ownership issues and prevent new ones from entering the
library.
One of the most common issues we have is use-after-free issues. The
continuation pattern makes these really tricky to debug because by the time a
segsegv is raised the context of what has caused the error is long gone.
The plan is to add allocators that can be turned on that can do the following,
in order of runtime cost.
1: no-op, forward through to default new/delete
2: make sure the memory given to the constructor is dirty, memset free'd memory
to 0
3: implement operator new with mmap, lock that region of memory once it's been
deleted; obviously this can't be left to run forever because the memory is
never unmapped
This should also put some groundwork in place for implementing specialized
allocators for tiny objects that we churn through like std::string.
was:
I propose implementing a set of memory new/delete pairs with additional
checking to detect double deletes, read-after-delete, and write-after-deletes
to help debug resource ownership issues and prevent new ones from entering the
library.
One of the most common issues we have is use-after-free issues. The
continuation pattern makes these really tricky to debug because by the time a
segsegv is raised the context of what has caused the error is long gone.
The plan is to add allocators that can be turned on that can do the following,
in order of runtime cost.
1: no-op, forward through to default new/delete
2: memset free'd memory to 0
3: implement operator new with mmap, lock that region of memory once it's been
deleted; obviously this can't be left to run forever because the memory is
never unmapped
This should also put some groundwork in place for implementing specialized
allocators for tiny objects that we churn through like std::string.
> libhdfs++: Implement debug allocators
> -------------------------------------
>
> Key: HDFS-10188
> URL: https://issues.apache.org/jira/browse/HDFS-10188
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: hdfs-client
> Reporter: James Clampffer
> Assignee: James Clampffer
>
> I propose implementing a set of memory new/delete pairs with additional
> checking to detect double deletes, read-after-delete, and write-after-deletes
> to help debug resource ownership issues and prevent new ones from entering
> the library.
> One of the most common issues we have is use-after-free issues. The
> continuation pattern makes these really tricky to debug because by the time a
> segsegv is raised the context of what has caused the error is long gone.
> The plan is to add allocators that can be turned on that can do the
> following, in order of runtime cost.
> 1: no-op, forward through to default new/delete
> 2: make sure the memory given to the constructor is dirty, memset free'd
> memory to 0
> 3: implement operator new with mmap, lock that region of memory once it's
> been deleted; obviously this can't be left to run forever because the memory
> is never unmapped
> This should also put some groundwork in place for implementing specialized
> allocators for tiny objects that we churn through like std::string.
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