1 files changed, 24 insertions, 31 deletions

diff --git a/fs/proc/array.c b/fs/proc/array.c
index 55ed3510d2bb..42932f88141a 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -157,13 +157,11 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
 	unsigned int max_fds = 0;
 
 	rcu_read_lock();
-	ppid = pid_alive(p) ?
-		task_tgid_nr_ns(rcu_dereference(p->real_parent), ns) : 0;
-
 	tracer = ptrace_parent(p);
 	if (tracer)
 		tpid = task_pid_nr_ns(tracer, ns);
 
+	ppid = task_ppid_nr_ns(p, ns);
 	tgid = task_tgid_nr_ns(p, ns);
 	ngid = task_numa_group_id(p);
 	cred = get_task_cred(p);
@@ -422,7 +420,7 @@ static inline void task_thp_status(struct seq_file *m, struct mm_struct *mm)
 	bool thp_enabled = IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE);
 
 	if (thp_enabled)
-		thp_enabled = !test_bit(MMF_DISABLE_THP, &mm->flags);
+		thp_enabled = !mm_flags_test(MMF_DISABLE_THP_COMPLETELY, mm);
 	seq_printf(m, "THP_enabled:\t%d\n", thp_enabled);
 }
 
@@ -483,7 +481,6 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
 	unsigned long flags;
 	int exit_code = task->exit_code;
 	struct signal_struct *sig = task->signal;
-	unsigned int seq = 1;
 
 	state = *get_task_state(task);
 	vsize = eip = esp = 0;
@@ -500,7 +497,7 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
 		 * a program is not able to use ptrace(2) in that case. It is
 		 * safe because the task has stopped executing permanently.
 		 */
-		if (permitted && (task->flags & (PF_EXITING|PF_DUMPCORE))) {
+		if (permitted && (task->flags & (PF_EXITING|PF_DUMPCORE|PF_POSTCOREDUMP))) {
 			if (try_get_task_stack(task)) {
 				eip = KSTK_EIP(task);
 				esp = KSTK_ESP(task);
@@ -540,33 +537,29 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
 	if (permitted && (!whole || num_threads < 2))
 		wchan = !task_is_running(task);
 
-	do {
-		seq++; /* 2 on the 1st/lockless path, otherwise odd */
-		flags = read_seqbegin_or_lock_irqsave(&sig->stats_lock, &seq);
-
-		cmin_flt = sig->cmin_flt;
-		cmaj_flt = sig->cmaj_flt;
-		cutime = sig->cutime;
-		cstime = sig->cstime;
-		cgtime = sig->cgtime;
-
-		if (whole) {
-			struct task_struct *t;
-
-			min_flt = sig->min_flt;
-			maj_flt = sig->maj_flt;
-			gtime = sig->gtime;
-
-			rcu_read_lock();
-			__for_each_thread(sig, t) {
-				min_flt += t->min_flt;
-				maj_flt += t->maj_flt;
-				gtime += task_gtime(t);
+	scoped_guard(rcu) {
+		scoped_seqlock_read (&sig->stats_lock, ss_lock_irqsave) {
+			cmin_flt = sig->cmin_flt;
+			cmaj_flt = sig->cmaj_flt;
+			cutime = sig->cutime;
+			cstime = sig->cstime;
+			cgtime = sig->cgtime;
+
+			if (whole) {
+				struct task_struct *t;
+
+				min_flt = sig->min_flt;
+				maj_flt = sig->maj_flt;
+				gtime = sig->gtime;
+
+				__for_each_thread(sig, t) {
+					min_flt += t->min_flt;
+					maj_flt += t->maj_flt;
+					gtime += task_gtime(t);
+				}
 			}
-			rcu_read_unlock();
 		}
-	} while (need_seqretry(&sig->stats_lock, seq));
-	done_seqretry_irqrestore(&sig->stats_lock, seq, flags);
+	}
 
 	if (whole) {
 		thread_group_cputime_adjusted(task, &utime, &stime);