The 'ps' command is hanging on our Solaris 11 test environment. It does not respond to kill or even kill -9. This happens even when ps is called in its plain form with no arguments, and I tried it as two different users and as root, and it hung in all cases. At least, 'ptree' is still functioning. This happens only in the global zone.
I can think of two possible culprits. The first is that we blindly removed a zfs filesystem that had been delegated to a non-global zone. I shut that zone down and is now only in the 'installed' state, but it didn't make a difference. Truss actually shows 'ps' hanging shortly after this stat call to a different zone:
Both prstat and ptree are OK, but there is no /usr/ucb/ps (this is Solaris 11).
1. I had one zone root filesystem that was erroring on 'df' but that cleared after zfs umount
2: we are not using any naming services except for DNS
3: I am not having any trouble reading /proc in general.
I think it's getting stuck around the zcons driver. I have another truss showing ps getting stuck shortly after reading /etc/ttysrch, having just traversed /dev/term. /dev/zcons is next in the ttysearch list and 'ls /dev/zcons' hangs.