Early failures in Bluetooth HCI UART configuration leak SRCU percpu
memory.
When device initialization fails before hci_register_dev() completes,
the HCI_UNREGISTER flag is never set. As a result, when the device
reference count reaches zero, bt_host_release() evaluates this flag as
false and falls back to a direct kfree(hdev).
Because hci_release_dev() is bypassed, the SRCU struct initialized
early in hci_alloc_dev() is never cleaned up, resulting in a leak of
percpu memory.
Fix the leak by explicitly calling cleanup_srcu_struct() in the
fallback (unregistered) branch of bt_host_release() before freeing
the device.
Reported-by: syzbot+535ecc844591e50588a5@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=535ecc844591e50588a5
Tested-by: syzbot+535ecc844591e50588a5@syzkaller.appspotmail.com
Fixes: 1d6123102e9f ("Bluetooth: hci_core: Fix use-after-free in vhci_flush()")
Signed-off-by: Bharath Reddy <kbreddy.rpbc@gmail.com>
---
Changes in v5:
- Removed trailing whitespace in the version history to fix GitLint error
Changes in v4:
- Included patch version history
Changes in v3:
- Added missing curly braces to the if/else block in bt_host_release()
to resolve a checkpatch.pl warning
- Added Fixes and Closes tags
Changes in v2:
- Fixed a NULL pointer dereference caused by v1
- Moved cleanup_srcu_struct() to the fallback (unregistered) branch
of bt_host_release() instead of unconditionally calling hci_release_dev()
Changes in v1:
- Initial patch (failed because it bypassed the HCI_UNREGISTER check)
net/bluetooth/hci_sysfs.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/net/bluetooth/hci_sysfs.c b/net/bluetooth/hci_sysfs.c
index 041ce9adc378..8957ce7c21b7 100644
--- a/net/bluetooth/hci_sysfs.c
+++ b/net/bluetooth/hci_sysfs.c
@@ -83,10 +83,12 @@ static void bt_host_release(struct device *dev)
{
struct hci_dev *hdev = to_hci_dev(dev);
- if (hci_dev_test_flag(hdev, HCI_UNREGISTER))
+ if (hci_dev_test_flag(hdev, HCI_UNREGISTER)) {
hci_release_dev(hdev);
- else
+ } else {
+ cleanup_srcu_struct(&hdev->srcu);
kfree(hdev);
+ }
module_put(THIS_MODULE);
}
--
2.34.1