Single threaded process, running normally: mcvet@warbird:/proc/20911 >> ls -l total 0 dr-xr-xr-x 2 mcvet mcvet 0 Dec 18 16:23 attr -r-------- 1 mcvet mcvet 0 Dec 18 16:23 auxv -r--r--r-- 1 mcvet mcvet 0 Dec 18 16:23 cmdline -r--r--r-- 1 mcvet mcvet 0 Dec 18 16:23 cpuset lrwxrwxrwx 1 mcvet mcvet 0 Dec 18 16:23 cwd -> /home/mcvet/workspace/build/ frysk-core/frysk/bindir -r-------- 1 mcvet mcvet 0 Dec 18 16:23 environ lrwxrwxrwx 1 mcvet mcvet 0 Dec 18 16:23 exe -> /home/mcvet/stepper dr-x------ 2 mcvet mcvet 0 Dec 18 16:23 fd -rw-r--r-- 1 mcvet mcvet 0 Dec 18 16:23 loginuid -r-------- 1 mcvet mcvet 0 Dec 18 16:23 maps -rw------- 1 mcvet mcvet 0 Dec 18 16:23 mem -r--r--r-- 1 mcvet mcvet 0 Dec 18 16:23 mounts -r-------- 1 mcvet mcvet 0 Dec 18 16:23 mountstats -r--r--r-- 1 mcvet mcvet 0 Dec 18 16:23 numa_maps -rw-r--r-- 1 mcvet mcvet 0 Dec 18 16:23 oom_adj -r--r--r-- 1 mcvet mcvet 0 Dec 18 16:23 oom_score lrwxrwxrwx 1 mcvet mcvet 0 Dec 18 16:23 root -> / -r--r--r-- 1 mcvet mcvet 0 Dec 18 16:23 schedstat -r-------- 1 mcvet mcvet 0 Dec 18 16:23 smaps -r--r--r-- 1 mcvet mcvet 0 Dec 18 16:23 stat -r--r--r-- 1 mcvet mcvet 0 Dec 18 16:23 statm -r--r--r-- 1 mcvet mcvet 0 Dec 18 16:23 status dr-xr-xr-x 3 mcvet mcvet 0 Dec 18 16:23 task -r--r--r-- 1 mcvet mcvet 0 Dec 18 16:23 wchan Then, $ kill -11 20911 With Frysk sleeping in TaskObserver.Terminating.updateTerminated: mcvet@warbird:/proc/20911 >> ls -l ls: cannot read symbolic link cwd: Permission denied ls: cannot read symbolic link root: Permission denied ls: cannot read symbolic link exe: Permission denied total 0 dr-xr-xr-x 2 mcvet mcvet 0 Dec 18 16:23 attr -r-------- 1 root root 0 Dec 18 16:23 auxv -r--r--r-- 1 root root 0 Dec 18 16:23 cmdline -r--r--r-- 1 root root 0 Dec 18 16:23 cpuset lrwxrwxrwx 1 root root 0 Dec 18 16:23 cwd -r-------- 1 root root 0 Dec 18 16:23 environ lrwxrwxrwx 1 root root 0 Dec 18 16:23 exe dr-x------ 2 root root 0 Dec 18 16:23 fd -rw-r--r-- 1 root root 0 Dec 18 16:23 loginuid -r-------- 1 root root 0 Dec 18 16:23 maps -rw------- 1 root root 0 Dec 18 16:23 mem -r--r--r-- 1 root root 0 Dec 18 16:23 mounts -r-------- 1 root root 0 Dec 18 16:23 mountstats -r--r--r-- 1 root root 0 Dec 18 16:23 numa_maps -rw-r--r-- 1 root root 0 Dec 18 16:23 oom_adj -r--r--r-- 1 root root 0 Dec 18 16:23 oom_score lrwxrwxrwx 1 root root 0 Dec 18 16:23 root -r--r--r-- 1 root root 0 Dec 18 16:23 schedstat -r-------- 1 root root 0 Dec 18 16:23 smaps -r--r--r-- 1 root root 0 Dec 18 16:23 stat -r--r--r-- 1 root root 0 Dec 18 16:23 statm -r--r--r-- 1 root root 0 Dec 18 16:23 status dr-xr-xr-x 3 mcvet mcvet 0 Dec 18 16:23 task -r--r--r-- 1 root root 0 Dec 18 16:23 wchan Same story for /proc/$$/tasks/$$/.