[PATCH] Fix clang-tidy delete of stack object

Alexander Kornienko alexfh at google.com
Thu Nov 13 05:10:37 PST 2014 

Committed in r221884 + a regression test in r221885.

Aaron, thank you for the patch!

On Thu, Nov 13, 2014 at 10:20 AM, Manuel Klimek <klimek at google.com> wrote:

> +dblakie
>
> On Thu Nov 13 2014 at 1:53:39 AM Alexander Kornienko <alexfh at google.com>
> wrote:
>
>> Thank you for the analysis and the proposed solution!
>>
>> I can reproduce the issue (with any q.cpp that is not clang-tidy clean):
>>
>> $ clang-tidy q.cpp -- --serialize-diagnostics test.dia
>> *** Error in `clang_tidy': free(): invalid pointer: 0x00007fffa65bb4d8 ***
>> Aborted (core dumped)
>>
>>
>> The patch seems correct to me and the way to distinguish between owning
>> and non-owning constructors seems also fine. I'll commit the patch tomorrow
>> if nobody offers a better solution.
>>
>
> I don't really see anything better under the current restrictions. Perhaps
> David has an idea, he has done a lot of the unique_ptr migrations in llvm.
>
>
>>
>> -- Alex
>>
>> On Wed, Nov 12, 2014 at 9:32 PM, Aaron Wishnick <
>> aaron.s.wishnick at gmail.com> wrote:
>>
>>> Understanding the bug better, I've attached a patch that more correctly
>>> fixes this bug, by teaching ChainedDiagnosticConsumer how to not take
>>> ownership of one of its arguments, and having SetupSerializedDiagnostics()
>>> use it. Is there a more idiomatic way, in the LLVM project, of a "maybe"
>>> owning pointer? I see that some related functions take a "ShouldOwnClient"
>>> argument, but this seems a little more kludgy for two arguments with
>>> separate ownership.
>>>
>>> Thanks,
>>> Aaron
>>>
>>> On Wed, Nov 12, 2014 at 3:14 PM, Aaron Wishnick <
>>> aaron.s.wishnick at gmail.com> wrote:
>>>
>>>> Hi Alexander, sorry to dig up an old issue, but I've just gotten some
>>>> more time to look into it. This is still reproducing for me on trunk, and I
>>>> can see where the ChainedDiagnosticConsumer is created, as well as why it
>>>> ends up trying to free a stack object. In short, there's a function
>>>> SetupSerializedDiagnostics() in CompilerInstance.cpp that doesn't know how
>>>> to handle the case where its DiagnosticsEngine doesn't own its client. This
>>>> bug can be reproduced by using clang-tidy with a compilation database that
>>>> uses the "--serialize-diagnostics" flag.
>>>>
>>>> When I run a debug build with the arguments "clang-tidy -p
>>>> /path/to/compile_commands.json /path/to/source.cpp", I get a failed assert
>>>> in tools/clang/lib/Frontend/CompilerInstance.cpp, line 173, in
>>>> SetupSerializedDiagnostics():
>>>>
>>>> static void SetupSerializedDiagnostics(DiagnosticOptions *DiagOpts,
>>>>                                        DiagnosticsEngine &Diags,
>>>>                                        StringRef OutputFile) {
>>>>   auto SerializedConsumer =
>>>>       clang::serialized_diags::create(OutputFile, DiagOpts);
>>>>
>>>>   assert(Diags.ownsClient());
>>>>   Diags.setClient(new ChainedDiagnosticConsumer(
>>>>       std::unique_ptr<DiagnosticConsumer>(Diags.takeClient()),
>>>>       std::move(SerializedConsumer)));
>>>> }
>>>>
>>>> Stepping one stack frame up into createDiagnostics(), it looks like
>>>> this code path is hit because the "if
>>>> (!Opts->DiagnosticSerializationFile.empty())" condition on line 209 of
>>>> CompilerInstance.cpp is met.
>>>>
>>>> If I skip that assert, and continue, I get that same "pointer being
>>>> freed was not allocated" error, once the program finishes and the
>>>> ChainedDiagnosticConsumer is deleted. The address is from the stack, rather
>>>> than the heap, and it corresponds to the value of "Diags.Client" before
>>>> that call to "Diags.takeClient()." In other words, I think the problem is
>>>> that the DiagnosticsEngine passed into SetupSerializedDiagnostics doesn't
>>>> own its client, and the client is stack allocated, and then the client is
>>>> stored in a unique_ptr which is owned by the ChainedDiagnosticConsumer.
>>>>
>>>> Ultimately, I can see this comes from ClangTidy.cpp, line 470. This
>>>> ClangTidyDiagnosticConsumer is created on the stack, and is the one that
>>>> eventually ends up being freed, causing the bug.
>>>>
>>>> I am using this in conjunction with Xcode: I am using xcodebuild to
>>>> build my project, and then oclint-xcodebuild to generate the
>>>> compile_commands.json database. Sure enough, all of the commands in the
>>>> compilation database include the argument "--serialize-diagnostics
>>>> /path/to/source.dia". If I remove these arguments, this bug doesn't occur.
>>>> So, I think the issue is that SetupSerializedDiagnostics doesn't know how
>>>> to handle the case where the DiagnosticsEngine doesn't own its client.
>>>>
>>>> Hope this helps!
>>>>
>>>> Best,
>>>> Aaron
>>>>
>>>>
>>>> On Mon, Jun 23, 2014 at 9:51 AM, Alexander Kornienko <alexfh at google.com
>>>> > wrote:
>>>>
>>>>>
>>>>> On Mon, Jun 23, 2014 at 2:51 PM, Alexander Kornienko <
>>>>> alexfh at google.com> wrote:
>>>>>
>>>>>>
>>>>>> On Thu, Jun 19, 2014 at 5:59 PM, Aaron Wishnick <
>>>>>> aaron.s.wishnick at gmail.com> wrote:
>>>>>>
>>>>>>> When I run clang-tidy on OS X 10.9.3, I immediately get this output:
>>>>>>>
>>>>>>> clang-tidy(97903,0x7fff782fb310) malloc: *** error for object
>>>>>>> 0x7fff5fbfecd0: pointer being freed was not allocated
>>>>>>> *** set a breakpoint in malloc_error_break to debug
>>>>>>>
>>>>>>> This occurs inside the destructor of ClangTidyDiagnosticConsumer.
>>>>>>> Here's my callstack:
>>>>>>>
>>>>>>> #4 0x000000010058e3e2 in ~ClangTidyDiagnosticConsumer at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/tools/extra/clang-tidy/ClangTidyDiagnosticConsumer.h:190
>>>>>>> #5 0x0000000100656a73 in
>>>>>>> std::__1::default_delete<clang::DiagnosticConsumer>::operator()(clang::DiagnosticConsumer*)
>>>>>>> const [inlined] at
>>>>>>> /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/c++/v1/memory:2426
>>>>>>> #6 0x0000000100656a4b in
>>>>>>> std::__1::unique_ptr<clang::DiagnosticConsumer,
>>>>>>> std::__1::default_delete<clang::DiagnosticConsumer>
>>>>>>> >::reset(clang::DiagnosticConsumer*) [inlined] at
>>>>>>> /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/c++/v1/memory:2625
>>>>>>> #7 0x00000001006569f5 in ~unique_ptr [inlined] at
>>>>>>> /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/c++/v1/memory:2593
>>>>>>> #8 0x00000001006569f5 in ~unique_ptr [inlined] at
>>>>>>> /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/c++/v1/memory:2593
>>>>>>> #9 0x00000001006569f5 in ~ChainedDiagnosticConsumer at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/include/clang/Frontend/ChainedDiagnosticConsumer.h:23
>>>>>>> #10 0x0000000100656595 in ~ChainedDiagnosticConsumer at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/include/clang/Frontend/ChainedDiagnosticConsumer.h:23
>>>>>>> #11 0x00000001006565b9 in ~ChainedDiagnosticConsumer at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/include/clang/Frontend/ChainedDiagnosticConsumer.h:23
>>>>>>> #12 0x00000001015eec84 in ~DiagnosticsEngine at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/lib/Basic/Diagnostic.cpp:68
>>>>>>> #13 0x00000001015eec35 in ~DiagnosticsEngine at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/lib/Basic/Diagnostic.cpp:66
>>>>>>> #14 0x00000001006bd3d3 in
>>>>>>> llvm::RefCountedBase<clang::DiagnosticsEngine>::Release() const at
>>>>>>> /Users/awishnick/clang-tidy/llvm/include/llvm/ADT/IntrusiveRefCntPtr.h:55
>>>>>>> #15 0x00000001006bd325 in
>>>>>>> llvm::IntrusiveRefCntPtrInfo<clang::DiagnosticsEngine>::release(clang::DiagnosticsEngine*)
>>>>>>> at /Users/awishnick/clang-tidy/llvm/include/llvm/ADT/IntrusiveRefCntPtr.h:90
>>>>>>> #16 0x00000001006bd2fd in
>>>>>>> llvm::IntrusiveRefCntPtr<clang::DiagnosticsEngine>::release() at
>>>>>>> /Users/awishnick/clang-tidy/llvm/include/llvm/ADT/IntrusiveRefCntPtr.h:199
>>>>>>> #17 0x00000001006bd2c5 in ~IntrusiveRefCntPtr at
>>>>>>> /Users/awishnick/clang-tidy/llvm/include/llvm/ADT/IntrusiveRefCntPtr.h:172
>>>>>>> #18 0x00000001006bbe15 in ~IntrusiveRefCntPtr at
>>>>>>> /Users/awishnick/clang-tidy/llvm/include/llvm/ADT/IntrusiveRefCntPtr.h:172
>>>>>>> #19 0x000000010065cbc1 in ~CompilerInstance at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/lib/Frontend/CompilerInstance.cpp:63
>>>>>>> #20 0x000000010065c505 in ~CompilerInstance at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/lib/Frontend/CompilerInstance.cpp:61
>>>>>>> #21 0x00000001005d6474 in
>>>>>>> clang::tooling::FrontendActionFactory::runInvocation(clang::CompilerInvocation*,
>>>>>>> clang::FileManager*, clang::DiagnosticConsumer*) at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/lib/Tooling/Tooling.cpp:270
>>>>>>> #22 0x00000001005d614f in
>>>>>>> clang::tooling::ToolInvocation::runInvocation(char const*,
>>>>>>> clang::driver::Compilation*, clang::CompilerInvocation*) at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/lib/Tooling/Tooling.cpp:243
>>>>>>> #23 0x00000001005d5290 in clang::tooling::ToolInvocation::run() at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/lib/Tooling/Tooling.cpp:229
>>>>>>> #24 0x00000001005d7b29 in
>>>>>>> clang::tooling::ClangTool::run(clang::tooling::ToolAction*) at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/lib/Tooling/Tooling.cpp:360
>>>>>>> #25 0x0000000100566cd2 in
>>>>>>> clang::tidy::runClangTidy(clang::tidy::ClangTidyOptionsProvider*,
>>>>>>> clang::tooling::CompilationDatabase const&,
>>>>>>> llvm::ArrayRef<std::__1::basic_string<char, std::__1::char_traits<char>,
>>>>>>> std::__1::allocator<char> > >,
>>>>>>> std::__1::vector<clang::tidy::ClangTidyError,
>>>>>>> std::__1::allocator<clang::tidy::ClangTidyError> >*) at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/tools/extra/clang-tidy/ClangTidy.cpp:345
>>>>>>> #26 0x0000000100002a96 in main at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/tools/extra/clang-tidy/tool/ClangTidyMain.cpp:145
>>>>>>>
>>>>>>> In short, it appears that ClangTool takes ownership of the
>>>>>>> diagnostic consumer, but it's being allocated on the stack. My fix is to
>>>>>>> allocate it on the heap instead. I've attached my patch. Please let me know
>>>>>>> if this assessment is incorrect, or if you'd like me to go about this
>>>>>>> differently.
>>>>>>>
>>>>>>
>>>>>> Well, the ownership of the diagnostic consumer shouldn't be
>>>>>> transferred, and I don't see any evidence ClangTool::setDiagnosticConsumer
>>>>>> expects this to happen. This all looks strange, and I'm investigating this.
>>>>>>
>>>>>
>>>>> I wasn't able to reproduce this crash. Your stack trace has
>>>>> ChainedDiagnosticConsumer in it, which afaiu, it is only used twice in
>>>>> Clang, and both places don't seem to be unrelated to clang-tidy. Could you
>>>>> set a breakpoint in ChainedDiagnosticConsumer constructor and send me the
>>>>> stack trace where it gets called in clang-tidy? (or add an "assert(false);"
>>>>> there to get the stack trace on the console in the assertions-enabled build)
>>>>>
>>>>>
>>>>>>
>>>>>>
>>>>>>>
>>>>>>> Thanks!
>>>>>>> Aaron
>>>>>>>
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> cfe-commits mailing list
>>>>>>> cfe-commits at cs.uiuc.edu
>>>>>>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
>>>>>>
>>>>>>
>>>>
>>>> On Mon, Jun 23, 2014 at 9:51 AM, Alexander Kornienko <alexfh at google.com
>>>> > wrote:
>>>>
>>>>>
>>>>> On Mon, Jun 23, 2014 at 2:51 PM, Alexander Kornienko <
>>>>> alexfh at google.com> wrote:
>>>>>
>>>>>>
>>>>>> On Thu, Jun 19, 2014 at 5:59 PM, Aaron Wishnick <
>>>>>> aaron.s.wishnick at gmail.com> wrote:
>>>>>>
>>>>>>> When I run clang-tidy on OS X 10.9.3, I immediately get this output:
>>>>>>>
>>>>>>> clang-tidy(97903,0x7fff782fb310) malloc: *** error for object
>>>>>>> 0x7fff5fbfecd0: pointer being freed was not allocated
>>>>>>> *** set a breakpoint in malloc_error_break to debug
>>>>>>>
>>>>>>> This occurs inside the destructor of ClangTidyDiagnosticConsumer.
>>>>>>> Here's my callstack:
>>>>>>>
>>>>>>> #4 0x000000010058e3e2 in ~ClangTidyDiagnosticConsumer at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/tools/extra/clang-tidy/ClangTidyDiagnosticConsumer.h:190
>>>>>>> #5 0x0000000100656a73 in
>>>>>>> std::__1::default_delete<clang::DiagnosticConsumer>::operator()(clang::DiagnosticConsumer*)
>>>>>>> const [inlined] at
>>>>>>> /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/c++/v1/memory:2426
>>>>>>> #6 0x0000000100656a4b in
>>>>>>> std::__1::unique_ptr<clang::DiagnosticConsumer,
>>>>>>> std::__1::default_delete<clang::DiagnosticConsumer>
>>>>>>> >::reset(clang::DiagnosticConsumer*) [inlined] at
>>>>>>> /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/c++/v1/memory:2625
>>>>>>> #7 0x00000001006569f5 in ~unique_ptr [inlined] at
>>>>>>> /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/c++/v1/memory:2593
>>>>>>> #8 0x00000001006569f5 in ~unique_ptr [inlined] at
>>>>>>> /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/c++/v1/memory:2593
>>>>>>> #9 0x00000001006569f5 in ~ChainedDiagnosticConsumer at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/include/clang/Frontend/ChainedDiagnosticConsumer.h:23
>>>>>>> #10 0x0000000100656595 in ~ChainedDiagnosticConsumer at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/include/clang/Frontend/ChainedDiagnosticConsumer.h:23
>>>>>>> #11 0x00000001006565b9 in ~ChainedDiagnosticConsumer at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/include/clang/Frontend/ChainedDiagnosticConsumer.h:23
>>>>>>> #12 0x00000001015eec84 in ~DiagnosticsEngine at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/lib/Basic/Diagnostic.cpp:68
>>>>>>> #13 0x00000001015eec35 in ~DiagnosticsEngine at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/lib/Basic/Diagnostic.cpp:66
>>>>>>> #14 0x00000001006bd3d3 in
>>>>>>> llvm::RefCountedBase<clang::DiagnosticsEngine>::Release() const at
>>>>>>> /Users/awishnick/clang-tidy/llvm/include/llvm/ADT/IntrusiveRefCntPtr.h:55
>>>>>>> #15 0x00000001006bd325 in
>>>>>>> llvm::IntrusiveRefCntPtrInfo<clang::DiagnosticsEngine>::release(clang::DiagnosticsEngine*)
>>>>>>> at /Users/awishnick/clang-tidy/llvm/include/llvm/ADT/IntrusiveRefCntPtr.h:90
>>>>>>> #16 0x00000001006bd2fd in
>>>>>>> llvm::IntrusiveRefCntPtr<clang::DiagnosticsEngine>::release() at
>>>>>>> /Users/awishnick/clang-tidy/llvm/include/llvm/ADT/IntrusiveRefCntPtr.h:199
>>>>>>> #17 0x00000001006bd2c5 in ~IntrusiveRefCntPtr at
>>>>>>> /Users/awishnick/clang-tidy/llvm/include/llvm/ADT/IntrusiveRefCntPtr.h:172
>>>>>>> #18 0x00000001006bbe15 in ~IntrusiveRefCntPtr at
>>>>>>> /Users/awishnick/clang-tidy/llvm/include/llvm/ADT/IntrusiveRefCntPtr.h:172
>>>>>>> #19 0x000000010065cbc1 in ~CompilerInstance at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/lib/Frontend/CompilerInstance.cpp:63
>>>>>>> #20 0x000000010065c505 in ~CompilerInstance at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/lib/Frontend/CompilerInstance.cpp:61
>>>>>>> #21 0x00000001005d6474 in
>>>>>>> clang::tooling::FrontendActionFactory::runInvocation(clang::CompilerInvocation*,
>>>>>>> clang::FileManager*, clang::DiagnosticConsumer*) at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/lib/Tooling/Tooling.cpp:270
>>>>>>> #22 0x00000001005d614f in
>>>>>>> clang::tooling::ToolInvocation::runInvocation(char const*,
>>>>>>> clang::driver::Compilation*, clang::CompilerInvocation*) at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/lib/Tooling/Tooling.cpp:243
>>>>>>> #23 0x00000001005d5290 in clang::tooling::ToolInvocation::run() at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/lib/Tooling/Tooling.cpp:229
>>>>>>> #24 0x00000001005d7b29 in
>>>>>>> clang::tooling::ClangTool::run(clang::tooling::ToolAction*) at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/lib/Tooling/Tooling.cpp:360
>>>>>>> #25 0x0000000100566cd2 in
>>>>>>> clang::tidy::runClangTidy(clang::tidy::ClangTidyOptionsProvider*,
>>>>>>> clang::tooling::CompilationDatabase const&,
>>>>>>> llvm::ArrayRef<std::__1::basic_string<char, std::__1::char_traits<char>,
>>>>>>> std::__1::allocator<char> > >,
>>>>>>> std::__1::vector<clang::tidy::ClangTidyError,
>>>>>>> std::__1::allocator<clang::tidy::ClangTidyError> >*) at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/tools/extra/clang-tidy/ClangTidy.cpp:345
>>>>>>> #26 0x0000000100002a96 in main at
>>>>>>> /Users/awishnick/clang-tidy/llvm/tools/clang/tools/extra/clang-tidy/tool/ClangTidyMain.cpp:145
>>>>>>>
>>>>>>> In short, it appears that ClangTool takes ownership of the
>>>>>>> diagnostic consumer, but it's being allocated on the stack. My fix is to
>>>>>>> allocate it on the heap instead. I've attached my patch. Please let me know
>>>>>>> if this assessment is incorrect, or if you'd like me to go about this
>>>>>>> differently.
>>>>>>>
>>>>>>
>>>>>> Well, the ownership of the diagnostic consumer shouldn't be
>>>>>> transferred, and I don't see any evidence ClangTool::setDiagnosticConsumer
>>>>>> expects this to happen. This all looks strange, and I'm investigating this.
>>>>>>
>>>>>
>>>>> I wasn't able to reproduce this crash. Your stack trace has
>>>>> ChainedDiagnosticConsumer in it, which afaiu, it is only used twice in
>>>>> Clang, and both places don't seem to be unrelated to clang-tidy. Could you
>>>>> set a breakpoint in ChainedDiagnosticConsumer constructor and send me the
>>>>> stack trace where it gets called in clang-tidy? (or add an "assert(false);"
>>>>> there to get the stack trace on the console in the assertions-enabled build)
>>>>>
>>>>>
>>>>>>
>>>>>>
>>>>>>>
>>>>>>> Thanks!
>>>>>>> Aaron
>>>>>>>
>>>>>>>  _______________________________________________
>> cfe-commits mailing list
>> cfe-commits at cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20141113/8836df4e/attachment.html>

More information about the cfe-commits mailing list