Downstream bug for Frysk: http://sourceware.org/bugzilla/show_bug.cgi?id=3754

We're just looking for clarification on what's happening here:

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 the process is sent a signal:

$ kill -11 20911

With the process blocked after receiving the signal:


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/$$/tasks/$$/.