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[PATCH 3.18 17/22] Bluetooth: hidp: fix possible might sleep error in hidp_session_thread

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3.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jeffy Chen <jeffy.chen@rock-chips.com>

commit 5da8e47d849d3d37b14129f038782a095b9ad049 upstream.

It looks like hidp_session_thread has same pattern as the issue reported in
old rfcomm:

	while (1) {
		set_current_state(TASK_INTERRUPTIBLE);
		if (condition)
			break;
		// may call might_sleep here
		schedule();
	}
	__set_current_state(TASK_RUNNING);

Which fixed at:
	dfb2fae Bluetooth: Fix nested sleeps

So let's fix it at the same way, also follow the suggestion of:
https://lwn.net/Articles/628628/

Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Tested-by: AL Yu-Chen Cho <acho@suse.com>
Tested-by: Rohit Vaswani <rvaswani@nvidia.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/bluetooth/hidp/core.c |   33 ++++++++++++++++++++++-----------
 1 file changed, 22 insertions(+), 11 deletions(-)

--- a/net/bluetooth/hidp/core.c
+++ b/net/bluetooth/hidp/core.c
@@ -36,6 +36,7 @@
 #define VERSION "1.2"
 
 static DECLARE_RWSEM(hidp_session_sem);
+static DECLARE_WAIT_QUEUE_HEAD(hidp_session_wq);
 static LIST_HEAD(hidp_session_list);
 
 static unsigned char hidp_keycode[256] = {
@@ -1056,12 +1057,12 @@ static int hidp_session_start_sync(struc
  * Wake up session thread and notify it to stop. This is asynchronous and
  * returns immediately. Call this whenever a runtime error occurs and you want
  * the session to stop.
- * Note: wake_up_process() performs any necessary memory-barriers for us.
+ * Note: wake_up_interruptible() performs any necessary memory-barriers for us.
  */
 static void hidp_session_terminate(struct hidp_session *session)
 {
 	atomic_inc(&session->terminate);
-	wake_up_process(session->task);
+	wake_up_interruptible(&hidp_session_wq);
 }
 
 /*
@@ -1168,7 +1169,9 @@ static void hidp_session_run(struct hidp
 	struct sock *ctrl_sk = session->ctrl_sock->sk;
 	struct sock *intr_sk = session->intr_sock->sk;
 	struct sk_buff *skb;
+	DEFINE_WAIT_FUNC(wait, woken_wake_function);
 
+	add_wait_queue(&hidp_session_wq, &wait);
 	for (;;) {
 		/*
 		 * This thread can be woken up two ways:
@@ -1176,12 +1179,10 @@ static void hidp_session_run(struct hidp
 		 *    session->terminate flag and wakes this thread up.
 		 *  - Via modifying the socket state of ctrl/intr_sock. This
 		 *    thread is woken up by ->sk_state_changed().
-		 *
-		 * Note: set_current_state() performs any necessary
-		 * memory-barriers for us.
 		 */
-		set_current_state(TASK_INTERRUPTIBLE);
 
+		/* Ensure session->terminate is updated */
+		smp_mb__before_atomic();
 		if (atomic_read(&session->terminate))
 			break;
 
@@ -1215,11 +1216,22 @@ static void hidp_session_run(struct hidp
 		hidp_process_transmit(session, &session->ctrl_transmit,
 				      session->ctrl_sock);
 
-		schedule();
+		wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
 	}
+	remove_wait_queue(&hidp_session_wq, &wait);
 
 	atomic_inc(&session->terminate);
-	set_current_state(TASK_RUNNING);
+
+	/* Ensure session->terminate is updated */
+	smp_mb__after_atomic();
+}
+
+static int hidp_session_wake_function(wait_queue_t *wait,
+				      unsigned int mode,
+				      int sync, void *key)
+{
+	wake_up_interruptible(&hidp_session_wq);
+	return false;
 }
 
 /*
@@ -1232,7 +1244,8 @@ static void hidp_session_run(struct hidp
 static int hidp_session_thread(void *arg)
 {
 	struct hidp_session *session = arg;
-	wait_queue_t ctrl_wait, intr_wait;
+	DEFINE_WAIT_FUNC(ctrl_wait, hidp_session_wake_function);
+	DEFINE_WAIT_FUNC(intr_wait, hidp_session_wake_function);
 
 	BT_DBG("session %p", session);
 
@@ -1242,8 +1255,6 @@ static int hidp_session_thread(void *arg
 	set_user_nice(current, -15);
 	hidp_set_timer(session);
 
-	init_waitqueue_entry(&ctrl_wait, current);
-	init_waitqueue_entry(&intr_wait, current);
 	add_wait_queue(sk_sleep(session->ctrl_sock->sk), &ctrl_wait);
 	add_wait_queue(sk_sleep(session->intr_sock->sk), &intr_wait);
 	/* This memory barrier is paired with wq_has_sleeper(). See

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[PATCH 3.18 00/22] 3.18.68-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:20 +0200
  [PATCH 3.18 19/22] Bluetooth: bnep: fix possible might sleep error in bnep_session Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:20 +0200
  [PATCH 3.18 05/22] irda: do not leak initialized list.dev to userspace Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:20 +0200
  [PATCH 3.18 20/22] iio: imu: adis16480: Fix acceleration scale factor for adis16480 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:20 +0200
  [PATCH 3.18 01/22] dccp: purge write queue in dccp_destroy_sock() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:20 +0200
  [PATCH 3.18 13/22] cifs: Fix df output for users with quota limits Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:20 +0200
  [PATCH 3.18 03/22] sctp: fully initialize the IPv6 address in sctp_v6_to_addr() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:20 +0200
  [PATCH 3.18 07/22] net_sched: fix order of queue length updates in qdisc_replace() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:20 +0200
  [PATCH 3.18 22/22] ACPI / APEI: Add missing synchronize_rcu() on NOTIFY_SCI removal Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:20 +0200
  [PATCH 3.18 17/22] Bluetooth: hidp: fix possible might sleep error in hidp_session_thread Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:20 +0200
  [PATCH 3.18 09/22] ALSA: core: Fix unexpected error at replacing user TLV Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:20 +0200
  [PATCH 3.18 06/22] net: sched: fix NULL pointer dereference when action calls some targets Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:20 +0200
  [PATCH 3.18 04/22] tcp: when rearming RTO, if RTO time is in past then fire RTO ASAP Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:20 +0200
  [PATCH 3.18 08/22] Input: trackpoint - add new trackpoint firmware ID Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:20 +0200
  [PATCH 3.18 12/22] tracing: Fix freeing of filter in create_filter() when set_str is false Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:30 +0200
  [PATCH 3.18 18/22] Bluetooth: cmtp: fix possible might sleep error in cmtp_session Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:30 +0200
  [PATCH 3.18 14/22] cifs: return ENAMETOOLONG for overlong names in cifs_open()/cifs_lookup() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:30 +0200
  [PATCH 3.18 02/22] dccp: defer ccid_hc_tx_delete() at dismantle time Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:30 +0200
  [PATCH 3.18 10/22] ALSA: hda - Add stereo mic quirk for Lenovo G50-70 (17aa:3978) Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:30 +0200
  [PATCH 3.18 16/22] perf/core: Fix group {cpu,task} validation Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:30 +0200
  [PATCH 3.18 21/22] staging: rtl8188eu: add RNX-N150NUB support Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-08-28 10:30 +0200
  Re: [PATCH 3.18 00/22] 3.18.68-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2017-08-28 21:40 +0200
  Re: [PATCH 3.18 00/22] 3.18.68-stable review Guenter Roeck <linux@roeck-us.net> - 2017-08-29 02:10 +0200

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