From 17b9c24b25bfe0c15e5075efc8a442240c4e895d Mon Sep 17 00:00:00 2001
From: Huang Yiwei <hyiwei@codeaurora.org>
Date: Wed, 7 Apr 2021 17:08:00 +0800
Subject: [PATCH] ANDROID: hung_task: Add vendor hook for hung task detect

Add vendor hook for hung task detect, so we can decide which
threads need to check, avoiding false alarms.

Bug: 188684133
Signed-off-by: Huang Yiwei <hyiwei@codeaurora.org>
Change-Id: I5d7dfeb071cbfda8121134c38a458202aaa3a8c6
---
 drivers/android/vendor_hooks.c  |  3 +++
 include/trace/hooks/hung_task.h | 24 ++++++++++++++++++++++++
 kernel/hung_task.c              | 12 +++++++++---
 3 files changed, 36 insertions(+), 3 deletions(-)
 create mode 100644 include/trace/hooks/hung_task.h

diff --git a/drivers/android/vendor_hooks.c b/drivers/android/vendor_hooks.c
index c53270805362..dea206f0816f 100644
--- a/drivers/android/vendor_hooks.c
+++ b/drivers/android/vendor_hooks.c
@@ -55,6 +55,7 @@
 #include <trace/hooks/vmscan.h>
 #include <trace/hooks/psi.h>
 #include <trace/hooks/selinux.h>
+#include <trace/hooks/hung_task.h>
 
 /*
  * Export tracepoints that act as a bare tracehook (ie: have no trace event
@@ -283,3 +284,5 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_update_topology_flags_workfn);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_of_i2c_get_board_info);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_cgroup_attach);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_mm_dirty_limits);
+EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_check_uninterruptible_tasks);
+EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_check_uninterruptible_tasks_dn);
diff --git a/include/trace/hooks/hung_task.h b/include/trace/hooks/hung_task.h
new file mode 100644
index 000000000000..b355828df349
--- /dev/null
+++ b/include/trace/hooks/hung_task.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM hung_task
+
+#define TRACE_INCLUDE_PATH trace/hooks
+
+#if !defined(_TRACE_HOOK_HUNG_TASK_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_HOOK_HUNG_TASK_H
+
+#include <linux/tracepoint.h>
+#include <trace/hooks/vendor_hooks.h>
+
+DECLARE_HOOK(android_vh_check_uninterruptible_tasks,
+	TP_PROTO(struct task_struct *t, unsigned long timeout,
+		bool *need_check),
+	TP_ARGS(t, timeout, need_check));
+
+DECLARE_HOOK(android_vh_check_uninterruptible_tasks_dn,
+	TP_PROTO(void *unused),
+	TP_ARGS(unused));
+
+#endif /* _TRACE_HOOK_HUNG_TASK_H */
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/kernel/hung_task.c b/kernel/hung_task.c
index 396ebaebea3f..5fc41fd89001 100644
--- a/kernel/hung_task.c
+++ b/kernel/hung_task.c
@@ -23,6 +23,8 @@
 #include <linux/sched/sysctl.h>
 
 #include <trace/events/sched.h>
+#undef CREATE_TRACE_POINTS
+#include <trace/hooks/hung_task.h>
 
 /*
  * The number of tasks checked:
@@ -177,6 +179,7 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout)
 	int max_count = sysctl_hung_task_check_count;
 	unsigned long last_break = jiffies;
 	struct task_struct *g, *t;
+	bool need_check = true;
 
 	/*
 	 * If the system crashed already then all bets are off,
@@ -195,10 +198,13 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout)
 				goto unlock;
 			last_break = jiffies;
 		}
-		/* use "==" to skip the TASK_KILLABLE tasks waiting on NFS */
-		if (t->state == TASK_UNINTERRUPTIBLE)
-			check_hung_task(t, timeout);
+		trace_android_vh_check_uninterruptible_tasks(t, timeout, &need_check);
+		if (need_check)
+			/* use "==" to skip the TASK_KILLABLE tasks waiting on NFS */
+			if (t->state == TASK_UNINTERRUPTIBLE)
+				check_hung_task(t, timeout);
 	}
+	trace_android_vh_check_uninterruptible_tasks_dn(NULL);
  unlock:
 	rcu_read_unlock();
 	if (hung_task_show_lock)