Bluetooth: hci_uart: add missing NULL check in h5_enqueue

Commit Message

Pavel Skripkin March 13, 2022, 5:49 p.m. UTC

Syzbot hit general protection fault in __pm_runtime_resume(). The problem
was in missing NULL check.

hu->serdev can be NULL and we should not blindly pass &serdev->dev
somewhere, since it will cause GPF.

Reported-by: [e-mail]
Fixes: d9dd833cf6d2 ("Bluetooth: hci_h5: Add runtime suspend")
Signed-off-by: Pavel Skripkin <[e-mail]>
---
 drivers/bluetooth/hci_h5.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

Comments

[e-mail] March 13, 2022, 7:04 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=622982

---Test result---

Test Summary:
CheckPatch                    PASS      1.70 seconds
GitLint                       PASS      1.03 seconds
SubjectPrefix                 PASS      0.89 seconds
BuildKernel                   PASS      35.65 seconds
BuildKernel32                 PASS      31.37 seconds
Incremental Build with patchesPASS      42.73 seconds
TestRunner: Setup             PASS      550.01 seconds
TestRunner: l2cap-tester      PASS      17.10 seconds
TestRunner: bnep-tester       PASS      7.11 seconds
TestRunner: mgmt-tester       PASS      112.17 seconds
TestRunner: rfcomm-tester     PASS      9.00 seconds
TestRunner: sco-tester        PASS      8.81 seconds
TestRunner: smp-tester        PASS      8.80 seconds
TestRunner: userchan-tester   PASS      7.39 seconds



---
Regards,
Linux Bluetooth

Marcel Holtmann March 14, 2022, 3:34 p.m. UTC | #2

Hi Pavel,

> Syzbot hit general protection fault in __pm_runtime_resume(). The problem
> was in missing NULL check.
> 
> hu->serdev can be NULL and we should not blindly pass &serdev->dev
> somewhere, since it will cause GPF.
> 
> Reported-by: [e-mail]
> Fixes: d9dd833cf6d2 ("Bluetooth: hci_h5: Add runtime suspend")
> Signed-off-by: Pavel Skripkin <[e-mail]>
> ---
> drivers/bluetooth/hci_h5.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)

patch has been applied to bluetooth-next tree.

However if someone would finally step up and write a standalone serdev only driver for 3-Wire UART support, this would not be a problem in the first place. We are just applying on bandaid after another.

Regards

Marcel

[e-mail] March 14, 2022, 3:40 p.m. UTC | #3

Hello:

This patch was applied to bluetooth/bluetooth-next.git (master)
by Marcel Holtmann <[e-mail]>:

On Sun, 13 Mar 2022 20:49:36 +0300 you wrote:
> Syzbot hit general protection fault in __pm_runtime_resume(). The problem
> was in missing NULL check.
> 
> hu->serdev can be NULL and we should not blindly pass &serdev->dev
> somewhere, since it will cause GPF.
> 
> Reported-by: [e-mail]
> Fixes: d9dd833cf6d2 ("Bluetooth: hci_h5: Add runtime suspend")
> Signed-off-by: Pavel Skripkin <[e-mail]>
> 
> [...]

Here is the summary with links:
  - Bluetooth: hci_uart: add missing NULL check in h5_enqueue
    https://git.kernel.org/bluetooth/bluetooth-next/c/928df045e94e

You are awesome, thank you!

Patch

diff --git a/drivers/bluetooth/hci_h5.c b/drivers/bluetooth/hci_h5.c
index 34286ffe0568..7ac6908a4dfb 100644
--- a/drivers/bluetooth/hci_h5.c
+++ b/drivers/bluetooth/hci_h5.c
@@ -629,9 +629,11 @@  static int h5_enqueue(struct hci_uart *hu, struct sk_buff *skb)
 		break;
 	}
 
-	pm_runtime_get_sync(&hu->serdev->dev);
-	pm_runtime_mark_last_busy(&hu->serdev->dev);
-	pm_runtime_put_autosuspend(&hu->serdev->dev);
+	if (hu->serdev) {
+		pm_runtime_get_sync(&hu->serdev->dev);
+		pm_runtime_mark_last_busy(&hu->serdev->dev);
+		pm_runtime_put_autosuspend(&hu->serdev->dev);
+	}
 
 	return 0;
 }