Track maximum number of processes per user and present it
in /proc/self/limits.
Signed-off-by: Topi Miettinen <toiwo...@gmail.com>
---
fs/proc/base.c | 4 ++++
include/linux/sched.h | 1 +
kernel/fork.c | 5 +++++
kernel/sys.c | 5 +++++
4 files changed, 15 insertions(+)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 1df4fc8..02576c6 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -670,6 +670,10 @@ static int proc_pid_limits(struct seq_file *m, struct
pid_namespace *ns,
seq_printf(m, "%-20lu\n", psecs);
}
break;
+ case RLIMIT_NPROC:
+ seq_printf(m, "%-20d\n",
+
atomic_read(&task->real_cred->user->max_processes));
+ break;
default:
seq_printf(m, "%-20lu\n",
task->signal->rlim_curmax[i]);
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 0150380..feb9bb7 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -838,6 +838,7 @@ static inline int signal_group_exit(const struct
signal_struct *sig)
struct user_struct {
atomic_t __count; /* reference count */
atomic_t processes; /* How many processes does this user have? */
+ atomic_t max_processes; /* How many processes has this user had at the
same time? */
atomic_t sigpending; /* How many pending signals does this user
have? */
#ifdef CONFIG_INOTIFY_USER
atomic_t inotify_watches; /* How many inotify watches does this user
have? */
diff --git a/kernel/fork.c b/kernel/fork.c
index 5c2c355..667290f 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1653,6 +1653,11 @@ static struct task_struct *copy_process(unsigned long
clone_flags,
trace_task_newtask(p, clone_flags);
uprobe_copy_process(p, clone_flags);
+ if (atomic_read(&p->real_cred->user->max_processes) <
+ atomic_read(&p->real_cred->user->processes))
+ atomic_set(&p->real_cred->user->max_processes,
+ atomic_read(&p->real_cred->user->processes));
+
return p;
bad_fork_cancel_cgroup:
diff --git a/kernel/sys.c b/kernel/sys.c
index 6629f6f..955cf21 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -439,6 +439,11 @@ static int set_user(struct cred *new)
else
current->flags &= ~PF_NPROC_EXCEEDED;
+ if (atomic_read(&new_user->max_processes) <
+ atomic_read(&new_user->processes))
+ atomic_set(&new_user->max_processes,
+ atomic_read(&new_user->processes));
+
free_uid(new->user);
new->user = new_user;
return 0;
--
2.8.1
