The patch titled
pid namespaces: destroy pid namespace on init's death
has been removed from the -mm tree. Its filename was
pid-namespaces-destroy-pid-namespace-on-inits-death.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: pid namespaces: destroy pid namespace on init's death
From: Sukadev Bhattiprolu <sukadev@xxxxxxxxxx>
Terminate all processes in a namespace when the reaper of the namespace is
exiting. We do this by walking the pidmap of the namespace and sending
SIGKILL to all processes.
Signed-off-by: Sukadev Bhattiprolu <sukadev@xxxxxxxxxx>
Acked-by: Pavel Emelyanov <xemul@xxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Sukadev Bhattiprolu <sukadev@xxxxxxxxxx>
Cc: Paul Menage <menage@xxxxxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/pid.h | 1 +
kernel/exit.c | 27 ++++++++++++++++++++++++++-
kernel/pid.c | 38 ++++++++++++++++++++++++++++++++++++++
3 files changed, 65 insertions(+), 1 deletion(-)
diff -puN include/linux/pid.h~pid-namespaces-destroy-pid-namespace-on-inits-death include/linux/pid.h
--- a/include/linux/pid.h~pid-namespaces-destroy-pid-namespace-on-inits-death
+++ a/include/linux/pid.h
@@ -125,6 +125,7 @@ extern struct pid *find_ge_pid(int nr, s
extern struct pid *alloc_pid(struct pid_namespace *ns);
extern void FASTCALL(free_pid(struct pid *pid));
+extern void zap_pid_ns_processes(struct pid_namespace *pid_ns);
/*
* the helpers to get the pid's id seen from different namespaces
diff -puN kernel/exit.c~pid-namespaces-destroy-pid-namespace-on-inits-death kernel/exit.c
--- a/kernel/exit.c~pid-namespaces-destroy-pid-namespace-on-inits-death
+++ a/kernel/exit.c
@@ -879,7 +879,32 @@ static inline void exit_child_reaper(str
if (likely(tsk->group_leader != task_child_reaper(tsk)))
return;
- panic("Attempted to kill init!");
+ if (tsk->nsproxy->pid_ns == &init_pid_ns)
+ panic("Attempted to kill init!");
+
+ /*
+ * @tsk is the last thread in the 'cgroup-init' and is exiting.
+ * Terminate all remaining processes in the namespace and reap them
+ * before exiting @tsk.
+ *
+ * Note that @tsk (last thread of cgroup-init) may not necessarily
+ * be the child-reaper (i.e main thread of cgroup-init) of the
+ * namespace i.e the child_reaper may have already exited.
+ *
+ * Even after a child_reaper exits, we let it inherit orphaned children,
+ * because, pid_ns->child_reaper remains valid as long as there is
+ * at least one living sub-thread in the cgroup init.
+
+ * This living sub-thread of the cgroup-init will be notified when
+ * a child inherited by the 'child-reaper' exits (do_notify_parent()
+ * uses __group_send_sig_info()). Further, when reaping child processes,
+ * do_wait() iterates over children of all living sub threads.
+
+ * i.e even though 'child_reaper' thread is listed as the parent of the
+ * orphaned children, any living sub-thread in the cgroup-init can
+ * perform the role of the child_reaper.
+ */
+ zap_pid_ns_processes(tsk->nsproxy->pid_ns);
}
fastcall NORET_TYPE void do_exit(long code)
diff -puN kernel/pid.c~pid-namespaces-destroy-pid-namespace-on-inits-death kernel/pid.c
--- a/kernel/pid.c~pid-namespaces-destroy-pid-namespace-on-inits-death
+++ a/kernel/pid.c
@@ -34,6 +34,7 @@
#include <linux/hash.h>
#include <linux/pid_namespace.h>
#include <linux/init_task.h>
+#include <linux/syscalls.h>
#define pid_hashfn(nr, ns) \
hash_long((unsigned long)nr + (unsigned long)ns, pidhash_shift)
@@ -567,6 +568,43 @@ void free_pid_ns(struct kref *kref)
put_pid_ns(parent);
}
+void zap_pid_ns_processes(struct pid_namespace *pid_ns)
+{
+ int nr;
+ int rc;
+
+ /*
+ * The last thread in the cgroup-init thread group is terminating.
+ * Find remaining pid_ts in the namespace, signal and wait for them
+ * to exit.
+ *
+ * Note: This signals each threads in the namespace - even those that
+ * belong to the same thread group, To avoid this, we would have
+ * to walk the entire tasklist looking a processes in this
+ * namespace, but that could be unnecessarily expensive if the
+ * pid namespace has just a few processes. Or we need to
+ * maintain a tasklist for each pid namespace.
+ *
+ */
+ read_lock(&tasklist_lock);
+ nr = next_pidmap(pid_ns, 1);
+ while (nr > 0) {
+ kill_proc_info(SIGKILL, SEND_SIG_PRIV, nr);
+ nr = next_pidmap(pid_ns, nr);
+ }
+ read_unlock(&tasklist_lock);
+
+ do {
+ clear_thread_flag(TIF_SIGPENDING);
+ rc = sys_wait4(-1, NULL, __WALL, NULL);
+ } while (rc != -ECHILD);
+
+
+ /* Child reaper for the pid namespace is going away */
+ pid_ns->child_reaper = NULL;
+ return;
+}
+
/*
* The pid hash table is scaled according to the amount of memory in the
* machine. From a minimum of 16 slots up to 4096 slots at one gigabyte or
_
Patches currently in -mm which might be from sukadev@xxxxxxxxxx are
origin.patch
-
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