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POhow can i debug a C++ delete call on android NDK?
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copied!<p>I've a Android C++ application that is manged by the Java layer. In this code i use a old physics library (tokamak) and i do almost nothing, i create and delete the simulator like this:</p> <pre><code>static neSimulator *gSim; neV3 gravity; gravity.Set(0.0f, -10.f, 0.0f); neSimulatorSizeInfo sizeInfo; sizeInfo.rigidBodiesCount = 1; sizeInfo.animatedBodiesCount = 1; sizeInfo.geometriesCount = 2; sizeInfo.overlappedPairsCount = 2; gSim = neSimulator::CreateSimulator(sizeInfo, NULL, &gravity); </code></pre> <p>And the destroy it:</p> <pre><code>neSimulator::CreateSimulator(gSim); </code></pre> <p>This works, the problem appears when i start adding geometry:</p> <pre><code>neV3 ballPos; rgdBall = gSim->CreateRigidBody(); neGeometry *geoBall = rgdBall->AddGeometry(); geoBall->SetSphereDiameter(1.5f); rgdBall->UpdateBoundingInfo(); rgdBall->SetMass(2.0f); rgdBall->SetInertiaTensor(neSphereInertiaTensor(1.5f, 2.0f)); ballPos.Set(0.0f, 5.0f, 0.0f); rgdBall->SetPos(ballPos); </code></pre> <p>In this case when i call the destroy (and i only call it once) i get a SIGSEGV (Null Pointer) deadbaad.</p> <p>I've all debugging log statements to the destructor method and the code inside the destructor completes to the end. So there is this code:</p> <pre><code>void neSimulator::DestroySimulator(neSimulator * sim) { __android_log_print(ANDROID_LOG_INFO, "TOKAMAK", "Before cast"); neFixedTimeStepSimulator * s = reinterpret_cast<neFixedTimeStepSimulator *>(sim); __android_log_print(ANDROID_LOG_INFO, "TOKAMAK", "After cast"); __android_log_print(ANDROID_LOG_INFO, "TOKAMAK", "Before delete"); delete s; __android_log_print(ANDROID_LOG_INFO, "TOKAMAK", "After delete"); } </code></pre> <p>So i log the destructor:</p> <pre><code>neFixedTimeStepSimulator::~neFixedTimeStepSimulator() { FreeAllBodies(); if (perf) delete perf; __android_log_print(ANDROID_LOG_INFO, "TOKAMAK", "dtor complete"); } </code></pre> <p>What is messing me is that i see the dtor complete message on the log but not the After delete message and a SIGSEGV error.</p> <p>How can i investigate it better?</p> <p>[More info after further investigation]</p> <p>So i used the addr2line tool to investigate the stack trace and traced the error to the default memory allocator. So i added logging to all alloc and free calls:</p> <pre><code>03-23 13:31:14.617: INFO/neAllocatorDefault(326): malloc 0x1b3fd8 size 2292 03-23 13:31:14.617: INFO/neAllocatorDefault(326): malloc 0x1b48d0 size 488 03-23 13:31:14.627: INFO/neAllocatorDefault(326): malloc 0x44ae3008 size 114404 03-23 13:31:14.627: INFO/neAllocatorDefault(326): malloc 0x1a58b8 size 8 03-23 13:31:14.627: INFO/neAllocatorDefault(326): malloc 0x1b4ac0 size 800 03-23 13:31:14.627: INFO/neAllocatorDefault(326): malloc 0x1b4de8 size 416 03-23 13:31:14.627: INFO/neAllocatorDefault(326): malloc 0x1b4f90 size 836 03-23 13:31:14.627: INFO/neAllocatorDefault(326): malloc 0x1aca10 size 44 03-23 13:31:14.627: INFO/neAllocatorDefault(326): malloc 0x1b52d8 size 2500 03-23 13:31:14.627: INFO/neAllocatorDefault(326): malloc 0x1b5ca0 size 2500 03-23 13:31:14.627: INFO/neAllocatorDefault(326): malloc 0x1b6668 size 2500 03-23 13:31:14.637: INFO/neAllocatorDefault(326): malloc 0x1b7030 size 400 03-23 13:31:14.637: INFO/neAllocatorDefault(326): malloc 0x1b71c8 size 800 03-23 13:31:14.637: INFO/neAllocatorDefault(326): malloc 0x424ed008 size 72404 03-23 13:31:14.637: INFO/neAllocatorDefault(326): malloc 0x1b74f0 size 4004 03-23 13:31:14.637: INFO/neAllocatorDefault(326): malloc 0x1b8498 size 2044 03-23 13:31:14.637: INFO/neAllocatorDefault(326): malloc 0x1b8c98 size 6044 03-23 13:31:14.637: INFO/neAllocatorDefault(326): malloc 0x1ba438 size 5004 03-23 13:31:14.637: INFO/neAllocatorDefault(326): malloc 0x1bb7c8 size 11204 03-23 13:31:14.637: INFO/neAllocatorDefault(326): malloc 0x1be390 size 340 03-23 13:31:14.637: INFO/neAllocatorDefault(326): malloc 0x1be4e8 size 4000 03-23 13:31:14.647: INFO/neAllocatorDefault(326): malloc 0x1bf490 size 4000 03-23 13:31:14.647: INFO/neAllocatorDefault(326): malloc 0x1c0438 size 38800 03-23 13:31:14.647: INFO/neAllocatorDefault(326): malloc 0x1c9bd0 size 38800 </code></pre> <p>And</p> <pre><code>03-23 13:31:19.508: INFO/neAllocatorDefault(326): free 0x1b71c8 03-23 13:31:19.508: INFO/neAllocatorDefault(326): free 0x1b7030 03-23 13:31:19.508: INFO/neAllocatorDefault(326): free 0x1b6668 03-23 13:31:19.508: INFO/neAllocatorDefault(326): free 0x1b5ca0 03-23 13:31:19.508: INFO/neAllocatorDefault(326): free 0x1b52d8 03-23 13:31:19.508: INFO/neAllocatorDefault(326): free 0x1aca10 03-23 13:31:19.508: INFO/neAllocatorDefault(326): free 0x1b4f90 03-23 13:31:19.508: INFO/neAllocatorDefault(326): free 0x1b4de8 03-23 13:31:19.508: INFO/neAllocatorDefault(326): free 0x1b4ac0 03-23 13:31:19.508: INFO/neAllocatorDefault(326): free 0x1a58b8 03-23 13:31:19.508: INFO/neAllocatorDefault(326): free 0x44ae3008 03-23 13:31:19.508: INFO/neAllocatorDefault(326): free 0x1b48d0 </code></pre> <p>So the SIGSEGV happens when trying to free 0x1b48d0, the funny thing is that there is a previous malloc that returned that pointer and no previous free. I am even more puzzled now...</p>

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