Possible access to freed stack memory in __kmpc_omp_wait_deps

[jprotze]

Bugzilla Link	49723
Resolution	FIXED
Resolved on	Oct 11, 2021 20:29
Version	unspecified
OS	Linux
Blocks	#51489
CC	@AndreyChurbanov,@jpeyton52,@modiking,@jprotze
Fixed by commit(s)	8e29b4b 2792379

Extended Description

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.

[AndreyChurbanov]

Better fix would be to not put stack-allocated node into dep hash, so that no references remained once the dependency is satisfied. Once this is barrier-like action, the node is not needed after the __kmpc_omp_wait_deps call.

[AndreyChurbanov]

Should be fixed by commit 8e29b4b.

[jprotze]

Thanks for fixing this issue!

I suggest that we backport this patch into release/13

[tstellar]

Merged: 2792379

[tstellar]

mentioned in issue #51489