On Thu, 22 Jan 2009, Boyce Griffith wrote: > Hi, Folks -- > > I am trying to track down a bug in some of my code using Valgrind 3.4.0. I'm > using OpenMPI 1.3, which directly integrates with Valgrind. Unfortunately, I > have not completed the process of transitioning my code from PETSc 2.3.3 to > 3.0.0, so these runs are using PETSc 2.3.3-p15. > > Running my code with Valgrind, I get a number of errors like the following: > > Invalid read of size 8 > at 0x6104C8F: UnPack_1 (vpscat.c:421) > by 0x61047A4: VecScatterEnd_1 (vpscat.h:150) > by 0x6133B2B: VecScatterEnd (vscat.c:1564) > by 0xC6A258: IBTK::LDataManager::endDataRedistribution(int, int) > (LDataManager.C:1200) > by 0xA0AEF2: IBAMR::IBStaggeredHierarchyIntegrator::regridHierarchy() > (IBStaggeredHierarchyIntegrator.C:1196) > by 0xA0CF53: > IBAMR::IBStaggeredHierarchyIntegrator::advanceHierarchy(double) > (IBStaggeredHierarchyIntegrator.C:653) > by 0x7308C4: main (main.C:798) > Address 0xa66bfd0 is 496 bytes inside a block of size 528 alloc'd > at 0x4A05FBB: malloc (vg_replace_malloc.c:207) > by 0x63DCFAF: PetscMallocAlign (mal.c:40) > by 0x63EA8A0: PetscTrMallocDefault (mtr.c:194) > by 0x611BDB2: VecScatterCreate_PtoS (vpscat.c:1570) > by 0x6121252: VecScatterCreate_StoP (vpscat.c:1946) > by 0x6122D2D: VecScatterCreate_PtoP (vpscat.c:2123) > by 0x6131B08: VecScatterCreate (vscat.c:1380) > by 0xC6960F: IBTK::LDataManager::endDataRedistribution(int, int) > (LDataManager.C:1158) > by 0xA0AEF2: IBAMR::IBStaggeredHierarchyIntegrator::regridHierarchy() > (IBStaggeredHierarchyIntegrator.C:1196) > by 0xA0CF53: > IBAMR::IBStaggeredHierarchyIntegrator::advanceHierarchy(double) > (IBStaggeredHierarchyIntegrator.C:653) > by 0x7308C4: main (main.C:798) > > Has anyone seen this kind of error crop up before? Does it indicate that I am > messing up the call to VecScatterCreate? (This VecScatter is being used to > scatter data between ghosted Vecs, and I wouldn't be shocked if I have made a > dumb mistake.) Could Valgrind be returning a false positive?
Most likely valgrind is correct here. However its a challenge determining where exactly the bug is - that is causing this behavior.. Checking ScatterCreate() and ScatterBegin() - and making sure that same vector [or dupes] are specified to these routines is a start... It is also possible that there was some other memory corruption much earlier than this piece of code that valgrind couldn't detect [so there is some garage already in some arrays]. And this garbage is now causing bad memory access - thus this error. Satish > > Again, this is with PETSc 2.3.3-p15. I am working on getting things up and > running with PETSc 3.0.0. > > Thanks! > > -- Boyce >
