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Posted to dev@qpid.apache.org by Jim Meyering <ji...@meyering.net> on 2007/01/12 16:50:43 UTC

C++: ack.range used uninitialized via bdbstore tests

In testing the bdbstore code, I found that AccumulatedAck.range
is used uninitialized.  Here's part of valgrind's report:

==3863== Thread 7:
==3863== Conditional jump or move depends on uninitialised value(s)
==3863==    at 0x4B4A63F: qpid::broker::AccumulatedAck::update(unsigned long, bool) (AccumulatedAck.cpp:29)
==3863==    by 0x4B6DE21: qpid::broker::SessionHandlerImpl::BasicHandlerImpl::ack(unsigned short, unsigned long, bool) (SessionHandlerImpl.cpp:427)
==3863==    by 0x4B6E8EF: qpid::broker::SessionHandlerImpl::received(qpid::framing::AMQFrame*) (SessionHandlerImpl.cpp:101)
==3863==    by 0x4CF5534: qpid::sys::LFSessionContext::read() (LFSessionContext.cpp:63)
==3863==    by 0x4CF44DD: qpid::sys::LFProcessor::run() (LFProcessor.cpp:125)
==3863==    by 0x4CF70A3: qpid::sys::Thread::runRunnable(apr_thread_t*, void*) (Thread.cpp:28)
==3863==    by 0x51BCF19: start_thread (in /usr/lib/debug/libpthread-2.3.6.so)
==3863==    by 0x5A2E5C1: clone (clone.S:112)

The code in question:

    25	void AccumulatedAck::update(u_int64_t tag, bool multiple){
    26	    if(multiple){
    27	        if(tag > range) range = tag;
    28	        //else don't care, it is already counted
    29	    }else if(tag > range){
    30	        individual.push_back(tag);
    31	    }
    32	}

Not surprisingly, the uses in qpidc's own tests do set the member first:

  ./tests/TxAckTest.cpp:        acked.range = 5;
  ./tests/AccumulatedAckTest.cpp:            ack.range = 5;

What do you think about making AccumulatedAck a class with the
sole constructor requiring an initializer for that member?
That should make it so this can't happen again.

Re: C++: ack.range used uninitialized via bdbstore tests

Posted by Alan Conway <ac...@redhat.com>.
On Fri, 2007-01-12 at 16:50 +0100, Jim Meyering wrote:
> In testing the bdbstore code, I found that AccumulatedAck.range
> is used uninitialized.  Here's part of valgrind's report:
> 
> ==3863== Thread 7:
> ==3863== Conditional jump or move depends on uninitialised value(s)
> ==3863==    at 0x4B4A63F: qpid::broker::AccumulatedAck::update(unsigned long, bool) (AccumulatedAck.cpp:29)
> ==3863==    by 0x4B6DE21: qpid::broker::SessionHandlerImpl::BasicHandlerImpl::ack(unsigned short, unsigned long, bool) (SessionHandlerImpl.cpp:427)
> ==3863==    by 0x4B6E8EF: qpid::broker::SessionHandlerImpl::received(qpid::framing::AMQFrame*) (SessionHandlerImpl.cpp:101)
> ==3863==    by 0x4CF5534: qpid::sys::LFSessionContext::read() (LFSessionContext.cpp:63)
> ==3863==    by 0x4CF44DD: qpid::sys::LFProcessor::run() (LFProcessor.cpp:125)
> ==3863==    by 0x4CF70A3: qpid::sys::Thread::runRunnable(apr_thread_t*, void*) (Thread.cpp:28)
> ==3863==    by 0x51BCF19: start_thread (in /usr/lib/debug/libpthread-2.3.6.so)
> ==3863==    by 0x5A2E5C1: clone (clone.S:112)
> 
> The code in question:
> 
>     25	void AccumulatedAck::update(u_int64_t tag, bool multiple){
>     26	    if(multiple){
>     27	        if(tag > range) range = tag;
>     28	        //else don't care, it is already counted
>     29	    }else if(tag > range){
>     30	        individual.push_back(tag);
>     31	    }
>     32	}
> 
> Not surprisingly, the uses in qpidc's own tests do set the member first:
> 
>   ./tests/TxAckTest.cpp:        acked.range = 5;
>   ./tests/AccumulatedAckTest.cpp:            ack.range = 5;
> 
> What do you think about making AccumulatedAck a class with the
> sole constructor requiring an initializer for that member?
> That should make it so this can't happen again.

That sounds right to me.