[v1] Bluetooth: hci_uart: fix race during initialization

Commit Message

Arseniy Krasnov Nov. 27, 2024, 12:38 p.m. UTC

'hci_register_dev()' calls power up function, which is executed by
kworker - 'hci_power_on()'. This function does access to bluetooth chip
using callbacks from 'hci_ldisc.c', for example 'hci_uart_send_frame()'.
Now 'hci_uart_send_frame()' checks 'HCI_UART_PROTO_READY' bit set, and
if not - it fails. Problem is that 'HCI_UART_PROTO_READY' is set after
'hci_register_dev()', and there is tiny chance that 'hci_power_on()' will
be executed before setting this bit. In that case HCI init logic fails.

Patch adds one more bit in addition to 'HCI_UART_PROTO_READY' which
allows to perform power up logic without original bit set.

Signed-off-by: Arseniy Krasnov <[e-mail]>
---
 drivers/bluetooth/hci_ldisc.c | 19 ++++++++++++++-----
 drivers/bluetooth/hci_uart.h  |  1 +
 2 files changed, 15 insertions(+), 5 deletions(-)

Comments

[e-mail] Nov. 27, 2024, 1:21 p.m. UTC | #1

This is automated email and please do not reply to this email!

Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=912808

---Test result---

Test Summary:
CheckPatch                    PENDING   0.28 seconds
GitLint                       PENDING   0.25 seconds
SubjectPrefix                 PASS      0.09 seconds
BuildKernel                   PASS      24.87 seconds
CheckAllWarning               PASS      27.04 seconds
CheckSparse                   PASS      30.44 seconds
BuildKernel32                 PASS      24.55 seconds
TestRunnerSetup               PASS      435.17 seconds
TestRunner_l2cap-tester       PASS      20.15 seconds
TestRunner_iso-tester         FAIL      28.03 seconds
TestRunner_bnep-tester        PASS      4.81 seconds
TestRunner_mgmt-tester        PASS      122.28 seconds
TestRunner_rfcomm-tester      PASS      7.51 seconds
TestRunner_sco-tester         PASS      9.32 seconds
TestRunner_ioctl-tester       PASS      8.01 seconds
TestRunner_mesh-tester        FAIL      8.07 seconds
TestRunner_smp-tester         PASS      7.44 seconds
TestRunner_userchan-tester    PASS      5.00 seconds
IncrementalBuild              PENDING   0.46 seconds

Details
##############################
Test: CheckPatch - PENDING
Desc: Run checkpatch.pl script
Output:

##############################
Test: GitLint - PENDING
Desc: Run gitlint
Output:

##############################
Test: TestRunner_iso-tester - FAIL
Desc: Run iso-tester with test-runner
Output:
WARNING: possible circular locking dependency detected
Total: 124, Passed: 120 (96.8%), Failed: 0, Not Run: 4
##############################
Test: TestRunner_mesh-tester - FAIL
Desc: Run mesh-tester with test-runner
Output:
BUG: KASAN: slab-use-after-free in run_timer_softirq+0x76c/0x7d0
WARNING: CPU: 0 PID: 33 at kernel/workqueue.c:2257 __queue_work+0x687/0xb40
Total: 10, Passed: 9 (90.0%), Failed: 1, Not Run: 0

Failed Test Cases
Mesh - Send cancel - 1                               Failed       0.103 seconds
##############################
Test: IncrementalBuild - PENDING
Desc: Incremental build with the patches in the series
Output:



---
Regards,
Linux Bluetooth

Patch

diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c
index 30192bb083549..2e20f00649bd7 100644
--- a/drivers/bluetooth/hci_ldisc.c
+++ b/drivers/bluetooth/hci_ldisc.c
@@ -102,7 +102,8 @@  static inline struct sk_buff *hci_uart_dequeue(struct hci_uart *hu)
 	if (!skb) {
 		percpu_down_read(&hu->proto_lock);
 
-		if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
+		if (test_bit(HCI_UART_PROTO_READY, &hu->flags) ||
+		    test_bit(HCI_UART_PROTO_INIT, &hu->flags))
 			skb = hu->proto->dequeue(hu);
 
 		percpu_up_read(&hu->proto_lock);
@@ -124,7 +125,8 @@  int hci_uart_tx_wakeup(struct hci_uart *hu)
 	if (!percpu_down_read_trylock(&hu->proto_lock))
 		return 0;
 
-	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags))
+	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags) &&
+	    !test_bit(HCI_UART_PROTO_INIT, &hu->flags))
 		goto no_schedule;
 
 	set_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
@@ -278,7 +280,8 @@  static int hci_uart_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
 
 	percpu_down_read(&hu->proto_lock);
 
-	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags)) {
+	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags) &&
+	    !test_bit(HCI_UART_PROTO_INIT, &hu->flags)) {
 		percpu_up_read(&hu->proto_lock);
 		return -EUNATCH;
 	}
@@ -582,7 +585,8 @@  static void hci_uart_tty_wakeup(struct tty_struct *tty)
 	if (tty != hu->tty)
 		return;
 
-	if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
+	if (test_bit(HCI_UART_PROTO_READY, &hu->flags) ||
+	    test_bit(HCI_UART_PROTO_INIT, &hu->flags))
 		hci_uart_tx_wakeup(hu);
 }
 
@@ -608,7 +612,8 @@  static void hci_uart_tty_receive(struct tty_struct *tty, const u8 *data,
 
 	percpu_down_read(&hu->proto_lock);
 
-	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags)) {
+	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags) &&
+	    !test_bit(HCI_UART_PROTO_INIT, &hu->flags)) {
 		percpu_up_read(&hu->proto_lock);
 		return;
 	}
@@ -704,12 +709,16 @@  static int hci_uart_set_proto(struct hci_uart *hu, int id)
 
 	hu->proto = p;
 
+	set_bit(HCI_UART_PROTO_INIT, &hu->flags);
+
 	err = hci_uart_register_dev(hu);
 	if (err) {
 		return err;
 	}
 
 	set_bit(HCI_UART_PROTO_READY, &hu->flags);
+	clear_bit(HCI_UART_PROTO_INIT, &hu->flags);
+
 	return 0;
 }
 
diff --git a/drivers/bluetooth/hci_uart.h b/drivers/bluetooth/hci_uart.h
index 00bf7ae82c5b7..39f39704be41f 100644
--- a/drivers/bluetooth/hci_uart.h
+++ b/drivers/bluetooth/hci_uart.h
@@ -89,6 +89,7 @@  struct hci_uart {
 #define HCI_UART_REGISTERED		1
 #define HCI_UART_PROTO_READY		2
 #define HCI_UART_NO_SUSPEND_NOTIFIER	3
+#define HCI_UART_PROTO_INIT		4
 
 /* TX states  */
 #define HCI_UART_SENDING	1