| Message ID | 20220407180651.14871-1-dossche.niels@gmail.com |
|---|---|
| State | Accepted |
| Commit | e05c3c0e1b45737c58292d59ade9fcb51ee95272 |
| Headers | show |
| Series | Bluetooth: use hdev lock in activate_scan for hci_is_adv_monitoring | expand |
Hello: This patch was applied to bluetooth/bluetooth-next.git (master) by Marcel Holtmann <marcel@holtmann.org>: On Thu, 7 Apr 2022 20:06:52 +0200 you wrote: > hci_is_adv_monitoring's function documentation states that it must be > called under the hdev lock. Paths that leads to an unlocked call are: > discov_update => start_discovery => interleaved_discov => active_scan > and: discov_update => start_discovery => active_scan > > The solution is to take the lock in active_scan during the duration of > the call to hci_is_adv_monitoring. > > [...] Here is the summary with links: - Bluetooth: use hdev lock in activate_scan for hci_is_adv_monitoring https://git.kernel.org/bluetooth/bluetooth-next/c/e05c3c0e1b45 You are awesome, thank you!
diff --git a/net/bluetooth/hci_request.c b/net/bluetooth/hci_request.c index 42c8047a9897..f4afe482e300 100644 --- a/net/bluetooth/hci_request.c +++ b/net/bluetooth/hci_request.c @@ -2260,6 +2260,7 @@ static int active_scan(struct hci_request *req, unsigned long opt) if (err < 0) own_addr_type = ADDR_LE_DEV_PUBLIC; + hci_dev_lock(hdev); if (hci_is_adv_monitoring(hdev)) { /* Duplicate filter should be disabled when some advertisement * monitor is activated, otherwise AdvMon can only receive one @@ -2276,6 +2277,7 @@ static int active_scan(struct hci_request *req, unsigned long opt) */ filter_dup = LE_SCAN_FILTER_DUP_DISABLE; } + hci_dev_unlock(hdev); hci_req_start_scan(req, LE_SCAN_ACTIVE, interval, hdev->le_scan_window_discovery, own_addr_type,
hci_is_adv_monitoring's function documentation states that it must be called under the hdev lock. Paths that leads to an unlocked call are: discov_update => start_discovery => interleaved_discov => active_scan and: discov_update => start_discovery => active_scan The solution is to take the lock in active_scan during the duration of the call to hci_is_adv_monitoring. Fixes: c32d624640fd ("Bluetooth: disable filter dup when scan for adv monitor") Signed-off-by: Niels Dossche <dossche.niels@gmail.com> --- Note: I am currently working on a static analyser to detect missing locks using type-based static analysis as my master's thesis in order to obtain my master's degree. If you would like to have more details, please let me know. This was a reported case. I manually verified the report by looking at the code, so that I do not send wrong information or patches. After concluding that this seems to be a true positive, I created this patch. I have only managed to compile-test this patch on x86_64. The effect on a running system could be a potential race condition in exceptional cases. This issue was found on Linux v5.17.1. net/bluetooth/hci_request.c | 2 ++ 1 file changed, 2 insertions(+)