1 files changed, 18 insertions, 28 deletions

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 989f35a2bbb1..1ddabefcfb5a 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -641,6 +641,8 @@ done:
 
 static int oom_reaper(void *unused)
 {
+	set_freezable();
+
 	while (true) {
 		struct task_struct *tsk = NULL;
 
@@ -787,9 +789,9 @@ static inline bool __task_will_free_mem(struct task_struct *task)
 	struct signal_struct *sig = task->signal;
 
 	/*
-	 * A coredumping process may sleep for an extended period in exit_mm(),
-	 * so the oom killer cannot assume that the process will promptly exit
-	 * and release memory.
+	 * A coredumping process may sleep for an extended period in
+	 * coredump_task_exit(), so the oom killer cannot assume that
+	 * the process will promptly exit and release memory.
 	 */
 	if (sig->flags & SIGNAL_GROUP_COREDUMP)
 		return false;
@@ -1120,27 +1122,24 @@ bool out_of_memory(struct oom_control *oc)
 }
 
 /*
- * The pagefault handler calls here because it is out of memory, so kill a
- * memory-hogging task. If oom_lock is held by somebody else, a parallel oom
- * killing is already in progress so do nothing.
+ * The pagefault handler calls here because some allocation has failed. We have
+ * to take care of the memcg OOM here because this is the only safe context without
+ * any locks held but let the oom killer triggered from the allocation context care
+ * about the global OOM.
  */
 void pagefault_out_of_memory(void)
 {
-	struct oom_control oc = {
-		.zonelist = NULL,
-		.nodemask = NULL,
-		.memcg = NULL,
-		.gfp_mask = 0,
-		.order = 0,
-	};
+	static DEFINE_RATELIMIT_STATE(pfoom_rs, DEFAULT_RATELIMIT_INTERVAL,
+				      DEFAULT_RATELIMIT_BURST);
 
 	if (mem_cgroup_oom_synchronize(true))
 		return;
 
-	if (!mutex_trylock(&oom_lock))
+	if (fatal_signal_pending(current))
 		return;
-	out_of_memory(&oc);
-	mutex_unlock(&oom_lock);
+
+	if (__ratelimit(&pfoom_rs))
+		pr_warn("Huh VM_FAULT_OOM leaked out to the #PF handler. Retrying PF\n");
 }
 
 SYSCALL_DEFINE2(process_mrelease, int, pidfd, unsigned int, flags)
@@ -1151,21 +1150,14 @@ SYSCALL_DEFINE2(process_mrelease, int, pidfd, unsigned int, flags)
 	struct task_struct *p;
 	unsigned int f_flags;
 	bool reap = false;
-	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;
-	}
+	task = pidfd_get_task(pidfd, &f_flags);
+	if (IS_ERR(task))
+		return PTR_ERR(task);
 
 	/*
 	 * Make sure to choose a thread which still has a reference to mm
@@ -1205,8 +1197,6 @@ drop_mm:
 		mmput(mm);
 put_task:
 	put_task_struct(task);
-put_pid:
-	put_pid(pid);
 	return ret;
 #else
 	return -ENOSYS;