pid_ns: Sleep in TASK_INTERRUPTIBLE in zap_pid_ns_processes

The code can potentially sleep for an indefinite amount of time in
zap_pid_ns_processes triggering the hung task timeout, and increasing
the system average.  This is undesirable.  Sleep with a task state of
TASK_INTERRUPTIBLE instead of TASK_UNINTERRUPTIBLE to remove these
undesirable side effects.

Apparently under heavy load this has been allowing Chrome to trigger
the hung time task timeout error and cause ChromeOS to reboot.

Reported-by: Vovo Yang <vovoy@google.com>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Fixes: 6347e9009104 ("pidns: guarantee that the pidns init will be the last pidns process reaped")
Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
index d1f3e9f558b84058e4f8ec88fdfddc647d2f704e..74a5a7255b4d9cb473cc7708d851c64402cca942 100644 (file)
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -277,7 +277,7 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns)
         * if reparented.
         */
        for (;;) {
-               set_current_state(TASK_UNINTERRUPTIBLE);
+               set_current_state(TASK_INTERRUPTIBLE);
                if (pid_ns->nr_hashed == init_pids)
                        break;
                schedule();