[llvm-bugs] [Bug 49723] New: Possible access to freed stack memory in __kmpc_omp_wait_deps

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=49723

            Bug ID: 49723
           Summary: Possible access to freed stack memory in
                    __kmpc_omp_wait_deps
           Product: OpenMP
           Version: unspecified
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: Runtime Library
          Assignee: unassignedbugs at nondot.org
          Reporter: protze at itc.rwth-aachen.de
                CC: llvm-bugs at lists.llvm.org

As reported in https://reviews.llvm.org/D96893, the test 
openmp/runtime/test/ompt/tasks/task_if0-depend.c leads to an assertion, when
the runtime is built in debug mode (the test triggers a KMP_DEBUG_ASSERT). 

Adding `KMP_ASSERT(node.dn.nrefs==1);` at the end of the `__kmpc_omp_wait_deps`
function reveals, that some depnodes still have references to the depnode
representing the task if0 dependency node. These depnodes will try to release
the stack-allocated depnode object, after it was destroyed by returning from
`__kmpc_omp_wait_deps`.

It might be necessary to replace the stack allocation by heap allocation.

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