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-rw-r--r--mm/oom_kill.c70
1 files changed, 70 insertions, 0 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index c729a4c4a1ac..831340e7ad8b 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -28,6 +28,7 @@
#include <linux/sched/task.h>
#include <linux/sched/debug.h>
#include <linux/swap.h>
+#include <linux/syscalls.h>
#include <linux/timex.h>
#include <linux/jiffies.h>
#include <linux/cpuset.h>
@@ -1141,3 +1142,72 @@ void pagefault_out_of_memory(void)
out_of_memory(&oc);
mutex_unlock(&oom_lock);
}
+
+SYSCALL_DEFINE2(process_mrelease, int, pidfd, unsigned int, flags)
+{
+#ifdef CONFIG_MMU
+ struct mm_struct *mm = NULL;
+ struct task_struct *task;
+ struct task_struct *p;
+ unsigned int f_flags;
+ bool reap = true;
+ struct pid *pid;
+ long ret = 0;
+
+ if (flags)
+ return -EINVAL;
+
+ pid = pidfd_get_pid(pidfd, &f_flags);
+ if (IS_ERR(pid))
+ return PTR_ERR(pid);
+
+ task = get_pid_task(pid, PIDTYPE_TGID);
+ if (!task) {
+ ret = -ESRCH;
+ goto put_pid;
+ }
+
+ /*
+ * Make sure to choose a thread which still has a reference to mm
+ * during the group exit
+ */
+ p = find_lock_task_mm(task);
+ if (!p) {
+ ret = -ESRCH;
+ goto put_task;
+ }
+
+ mm = p->mm;
+ mmgrab(mm);
+
+ /* If the work has been done already, just exit with success */
+ if (test_bit(MMF_OOM_SKIP, &mm->flags))
+ reap = false;
+ else if (!task_will_free_mem(p)) {
+ reap = false;
+ ret = -EINVAL;
+ }
+ task_unlock(p);
+
+ if (!reap)
+ goto drop_mm;
+
+ if (mmap_read_lock_killable(mm)) {
+ ret = -EINTR;
+ goto drop_mm;
+ }
+ if (!__oom_reap_task_mm(mm))
+ ret = -EAGAIN;
+ mmap_read_unlock(mm);
+
+drop_mm:
+ mmdrop(mm);
+put_task:
+ put_task_struct(task);
+put_pid:
+ put_pid(pid);
+ return ret;
+#else
+ return -ENOSYS;
+#endif /* CONFIG_MMU */
+}