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https://issues.apache.org/jira/browse/HDFS-10188?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15281627#comment-15281627
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James Clampffer commented on HDFS-10188:
----------------------------------------
I spoke too soon.. I ran locally as a sanity test before committing and
valgrind was unhappy:
{code}
[exec] ==15234== Invalid read of size 8
[exec] ==15234== at 0x6594D1: operator delete(void*) (string3.h:84)
[exec] ==15234== by 0x5567D84: ??? (in
/usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.19)
[exec] ==15234== by 0x5C7F258: __run_exit_handlers (exit.c:82)
[exec] ==15234== by 0x5C7F2A4: exit (exit.c:104)
[exec] ==15234== by 0x5C64ECB: (below main) (libc-start.c:321)
[exec] ==15234== Address 0x68127d8 is 8 bytes before a block of size 24
alloc'd
[exec] ==15234== at 0x4C2B3B0: operator new(unsigned long,
std::nothrow_t const&) (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
[exec] ==15234== by 0x5567EBD: __cxa_thread_atexit (in
/usr/lib/x86_64-linux-gnu/libstdc++.so.6.0.19)
[exec] ==15234== by 0x554846: ReportError(int, std::string const&)
(hdfs.cc:88)
[exec] ==15234== by 0x55602B: hdfsBuilderConfGetInt (hdfs.cc:673)
[exec] ==15234== by 0x522B42: HdfsBuilderTest_TestRead_Test::TestBody()
(hdfs_builder_test.cc:76)
[exec] ==15234== by 0x5531A2: void
testing::internal::HandleExceptionsInMethodIfSupported<testing::Test,
void>(testing::Test*, void (testing::Test::*)(), char const*)
(gmock-gtest-all.cc:3562)
[exec] ==15234== by 0x547256: testing::Test::Run()
(gmock-gtest-all.cc:3635)
[exec] ==15234== by 0x5472FD: testing::TestInfo::Run()
(gmock-gtest-all.cc:3810)
[exec] ==15234== by 0x547404: testing::TestCase::Run()
(gmock-gtest-all.cc:3928)
[exec] ==15234== by 0x5476B7:
testing::internal::UnitTestImpl::RunAllTests() (gmock-gtest-all.cc:5799)
[exec] ==15234== by 0x547973: testing::UnitTest::Run()
(gmock-gtest-all.cc:3562)
[exec] ==15234== by 0x51E1FF: main (gtest.h:20058)
[exec] ==15234==
{code}
Looks like gmock is newing objects with the default (or it's own) new
implementation and then freeing with the fancy delete. When the debug delete
decrements the address it ends up in memory it doesn't own.
Also get the following indicating default delete is being called on the
internal pointer created by the debug new.
{code}
*** Error in
`/home/jclampffer/apache_hadoop/hadoop-hdfs-project/hadoop-hdfs-native-client/target/main/native/libhdfspp/tests/libhdfs_threaded_hdfspp_test_shim_static':
free(): invalid pointer: 0x00007f7a98006938 ***
{code}
Seeming how this passed CI and in your machine I'm guessing it's a platform
dependent issue caused by the order of symbol resolution at link time.
> 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: Xiaowei Zhu
> Attachments: HDFS-10188.HDFS-8707.000.patch,
> HDFS-10188.HDFS-8707.001.patch
>
>
> 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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