The systemtap task_cwd_path() function results in an in-kernel memory leak

Issue

• The task_cwd_path() function in systemtap 3.0 is causing a memory leak in the kernel. The size of KernelStack increase as processes are executed in /proc/meminfo with a task_cwd_path() using systemtap script in use:

$ while [ 1 ]; do grep KernelStack: /proc/meminfo; sleep 1;  done
KernelStack:       89024 kB
KernelStack:       89040 kB
KernelStack:       89088 kB
KernelStack:       89552 kB
KernelStack:       89632 kB
KernelStack:       89712 kB
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