4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
commit b9a985db98961ae1ba0be169f19df1c567e4ffe0 upstream.
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@xxxxxxxxxx>
Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Tested-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Fixes: 6347e9009104 ("pidns: guarantee that the pidns init will be the last pidns process reaped")
Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/pid_namespace.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/pid_namespace.c
+++ b/kernel/pid_namespace.c
@@ -274,7 +274,7 @@ void zap_pid_ns_processes(struct pid_nam
* if reparented.
*/
for (;;) {
- set_current_state(TASK_UNINTERRUPTIBLE);
+ set_current_state(TASK_INTERRUPTIBLE);
if (pid_ns->nr_hashed == init_pids)
break;
schedule();