This is a note to let you know that I've just added the patch titled pid_ns: Sleep in TASK_INTERRUPTIBLE in zap_pid_ns_processes to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: pid_ns-sleep-in-task_interruptible-in-zap_pid_ns_processes.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From b9a985db98961ae1ba0be169f19df1c567e4ffe0 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> Date: Thu, 11 May 2017 18:21:01 -0500 Subject: pid_ns: Sleep in TASK_INTERRUPTIBLE in zap_pid_ns_processes 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 @@ -255,7 +255,7 @@ 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(); Patches currently in stable-queue which might be from ebiederm@xxxxxxxxxxxx are queue-4.4/proc-fix-unbalanced-hard-link-numbers.patch queue-4.4/pid_ns-sleep-in-task_interruptible-in-zap_pid_ns_processes.patch queue-4.4/pid_ns-fix-race-between-setns-ed-fork-and-zap_pid_ns_processes.patch