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-rw-r--r--kernel/exit.c13
-rw-r--r--kernel/fork.c42
-rw-r--r--kernel/sys.c22
-rw-r--r--kernel/trace/trace.c4
-rw-r--r--kernel/ucount.c6
5 files changed, 76 insertions, 11 deletions
diff --git a/kernel/exit.c b/kernel/exit.c
index 580da79e38ee..9960accbf2ab 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -607,15 +607,18 @@ static struct task_struct *find_new_reaper(struct task_struct *father,
return thread;
if (father->signal->has_child_subreaper) {
+ unsigned int ns_level = task_pid(father)->level;
/*
* Find the first ->is_child_subreaper ancestor in our pid_ns.
- * We start from father to ensure we can not look into another
- * namespace, this is safe because all its threads are dead.
+ * We can't check reaper != child_reaper to ensure we do not
+ * cross the namespaces, the exiting parent could be injected
+ * by setns() + fork().
+ * We check pid->level, this is slightly more efficient than
+ * task_active_pid_ns(reaper) != task_active_pid_ns(father).
*/
- for (reaper = father;
- !same_thread_group(reaper, child_reaper);
+ for (reaper = father->real_parent;
+ task_pid(reaper)->level == ns_level;
reaper = reaper->real_parent) {
- /* call_usermodehelper() descendants need this check */
if (reaper == &init_task)
break;
if (!reaper->signal->is_child_subreaper)
diff --git a/kernel/fork.c b/kernel/fork.c
index d12fcc4db8a3..348fe73155bc 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1377,9 +1377,6 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
sig->oom_score_adj = current->signal->oom_score_adj;
sig->oom_score_adj_min = current->signal->oom_score_adj_min;
- sig->has_child_subreaper = current->signal->has_child_subreaper ||
- current->signal->is_child_subreaper;
-
mutex_init(&sig->cred_guard_mutex);
return 0;
@@ -1814,6 +1811,13 @@ static __latent_entropy struct task_struct *copy_process(
p->signal->leader_pid = pid;
p->signal->tty = tty_kref_get(current->signal->tty);
+ /*
+ * Inherit has_child_subreaper flag under the same
+ * tasklist_lock with adding child to the process tree
+ * for propagate_has_child_subreaper optimization.
+ */
+ p->signal->has_child_subreaper = p->real_parent->signal->has_child_subreaper ||
+ p->real_parent->signal->is_child_subreaper;
list_add_tail(&p->sibling, &p->real_parent->children);
list_add_tail_rcu(&p->tasks, &init_task.tasks);
attach_pid(p, PIDTYPE_PGID);
@@ -2067,6 +2071,38 @@ SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp,
}
#endif
+void walk_process_tree(struct task_struct *top, proc_visitor visitor, void *data)
+{
+ struct task_struct *leader, *parent, *child;
+ int res;
+
+ read_lock(&tasklist_lock);
+ leader = top = top->group_leader;
+down:
+ for_each_thread(leader, parent) {
+ list_for_each_entry(child, &parent->children, sibling) {
+ res = visitor(child, data);
+ if (res) {
+ if (res < 0)
+ goto out;
+ leader = child;
+ goto down;
+ }
+up:
+ ;
+ }
+ }
+
+ if (leader != top) {
+ child = leader;
+ parent = child->real_parent;
+ leader = parent->group_leader;
+ goto up;
+ }
+out:
+ read_unlock(&tasklist_lock);
+}
+
#ifndef ARCH_MIN_MMSTRUCT_ALIGN
#define ARCH_MIN_MMSTRUCT_ALIGN 0
#endif
diff --git a/kernel/sys.c b/kernel/sys.c
index 7d4a9a6df956..b07adca97ea3 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -2063,6 +2063,24 @@ static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr)
}
#endif
+static int propagate_has_child_subreaper(struct task_struct *p, void *data)
+{
+ /*
+ * If task has has_child_subreaper - all its decendants
+ * already have these flag too and new decendants will
+ * inherit it on fork, skip them.
+ *
+ * If we've found child_reaper - skip descendants in
+ * it's subtree as they will never get out pidns.
+ */
+ if (p->signal->has_child_subreaper ||
+ is_child_reaper(task_pid(p)))
+ return 0;
+
+ p->signal->has_child_subreaper = 1;
+ return 1;
+}
+
SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
unsigned long, arg4, unsigned long, arg5)
{
@@ -2214,6 +2232,10 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
break;
case PR_SET_CHILD_SUBREAPER:
me->signal->is_child_subreaper = !!arg2;
+ if (!arg2)
+ break;
+
+ walk_process_tree(me, propagate_has_child_subreaper, NULL);
break;
case PR_GET_CHILD_SUBREAPER:
error = put_user(me->signal->is_child_subreaper,
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index d7449783987a..310f0ea0d1a2 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -7503,7 +7503,7 @@ init_tracer_tracefs(struct trace_array *tr, struct dentry *d_tracer)
ftrace_init_tracefs(tr, d_tracer);
}
-static struct vfsmount *trace_automount(void *ingore)
+static struct vfsmount *trace_automount(struct dentry *mntpt, void *ingore)
{
struct vfsmount *mnt;
struct file_system_type *type;
@@ -7516,7 +7516,7 @@ static struct vfsmount *trace_automount(void *ingore)
type = get_fs_type("tracefs");
if (!type)
return NULL;
- mnt = vfs_kern_mount(type, 0, "tracefs", NULL);
+ mnt = vfs_submount(mntpt, type, "tracefs", NULL);
put_filesystem(type);
if (IS_ERR(mnt))
return NULL;
diff --git a/kernel/ucount.c b/kernel/ucount.c
index 95c6336fc2b3..8a11fc0cb459 100644
--- a/kernel/ucount.c
+++ b/kernel/ucount.c
@@ -57,7 +57,7 @@ static struct ctl_table_root set_root = {
static int zero = 0;
static int int_max = INT_MAX;
-#define UCOUNT_ENTRY(name) \
+#define UCOUNT_ENTRY(name) \
{ \
.procname = name, \
.maxlen = sizeof(int), \
@@ -74,6 +74,10 @@ static struct ctl_table user_table[] = {
UCOUNT_ENTRY("max_net_namespaces"),
UCOUNT_ENTRY("max_mnt_namespaces"),
UCOUNT_ENTRY("max_cgroup_namespaces"),
+#ifdef CONFIG_INOTIFY_USER
+ UCOUNT_ENTRY("max_inotify_instances"),
+ UCOUNT_ENTRY("max_inotify_watches"),
+#endif
{ }
};
#endif /* CONFIG_SYSCTL */