[RESEND,v2] Bluetooth: hci_uart: fix race during initialization

Commit Message

Arseniy Krasnov Jan. 30, 2025, 6:43 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 moves setting of 'HCI_UART_PROTO_READY' before calling function
'hci_uart_register_dev()'.

Signed-off-by: Arseniy Krasnov <[e-mail]>
---
 Changelog v1->v2:
 * Move 'set_bit()' before 'hci_uart_register_dev()' instead of
   adding new bit 'HCI_UART_PROTO_INIT'.

 drivers/bluetooth/hci_ldisc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

[e-mail] Jan. 30, 2025, 7:01 p.m. UTC | #1

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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=929318

---Test result---

Test Summary:
CheckPatch                    PENDING   0.24 seconds
GitLint                       PENDING   0.19 seconds
SubjectPrefix                 PASS      0.11 seconds
BuildKernel                   PASS      24.52 seconds
CheckAllWarning               PASS      26.96 seconds
CheckSparse                   PASS      30.12 seconds
BuildKernel32                 PASS      24.45 seconds
TestRunnerSetup               PASS      422.74 seconds
TestRunner_l2cap-tester       PASS      20.28 seconds
TestRunner_iso-tester         PASS      29.18 seconds
TestRunner_bnep-tester        PASS      4.83 seconds
TestRunner_mgmt-tester        FAIL      119.73 seconds
TestRunner_rfcomm-tester      PASS      7.42 seconds
TestRunner_sco-tester         PASS      9.31 seconds
TestRunner_ioctl-tester       PASS      8.02 seconds
TestRunner_mesh-tester        PASS      5.96 seconds
TestRunner_smp-tester         PASS      7.02 seconds
TestRunner_userchan-tester    PASS      4.99 seconds
IncrementalBuild              PENDING   0.43 seconds

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

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

##############################
Test: TestRunner_mgmt-tester - FAIL
Desc: Run mgmt-tester with test-runner
Output:
Total: 490, Passed: 485 (99.0%), Failed: 1, Not Run: 4

Failed Test Cases
LL Privacy - Set Flags 3 (2 Devices to RL)           Failed       0.198 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..07b9aa09bbe2e 100644
--- a/drivers/bluetooth/hci_ldisc.c
+++ b/drivers/bluetooth/hci_ldisc.c
@@ -704,12 +704,13 @@  static int hci_uart_set_proto(struct hci_uart *hu, int id)
 
 	hu->proto = p;
 
+	set_bit(HCI_UART_PROTO_READY, &hu->flags);
+
 	err = hci_uart_register_dev(hu);
 	if (err) {
 		return err;
 	}
 
-	set_bit(HCI_UART_PROTO_READY, &hu->flags);
 	return 0;
 }