Hi Luiz, >>> Fault injection test reported memory leak of hci device as follows: >>> >>> unreferenced object 0xffff88800b858000 (size 8192): >>> comm "kworker/0:2", pid 167, jiffies 4294955747 (age 557.148s) >>> hex dump (first 32 bytes): >>> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >>> 00 00 00 00 00 00 00 00 00 00 00 00 ad 4e ad de .............N.. >>> backtrace: >>> [<0000000070eb1059>] kmem_cache_alloc_trace mm/slub.c:3208 >>> [<00000000015eb521>] hci_alloc_dev_priv include/linux/slab.h:591 >>> [<00000000dcfc1e21>] bpa10x_probe include/net/bluetooth/hci_core.h:1240 >>> [<000000005d3028c7>] usb_probe_interface drivers/usb/core/driver.c:397 >>> [<00000000cbac9243>] really_probe drivers/base/dd.c:517 >>> [<0000000024cab3f0>] __driver_probe_device drivers/base/dd.c:751 >>> [<00000000202135cb>] driver_probe_device drivers/base/dd.c:782 >>> [<000000000761f2bc>] __device_attach_driver drivers/base/dd.c:899 >>> [<00000000f7d63134>] bus_for_each_drv drivers/base/bus.c:427 >>> [<00000000c9551f0b>] __device_attach drivers/base/dd.c:971 >>> [<000000007f79bd16>] bus_probe_device drivers/base/bus.c:487 >>> [<000000007bb8b95a>] device_add drivers/base/core.c:3364 >>> [<000000009564d9ea>] usb_set_configuration drivers/usb/core/message.c:2171 >>> [<00000000e4657087>] usb_generic_driver_probe drivers/usb/core/generic.c:239 >>> [<0000000071ede518>] usb_probe_device drivers/usb/core/driver.c:294 >>> [<00000000cbac9243>] really_probe drivers/base/dd.c:517 >>> >>> hci_alloc_dev() do not init the device's flag. And hci_free_dev() >>> using put_device() to free the memory allocated for this device, >>> but it calls just kfree(dev) only in case of HCI_UNREGISTER flag >>> is set. So any error handing before hci_register_dev() success >>> will cause memory leak. >>> >>> To avoid this behaviour we need to set hdev HCI_UNREGISTER flag >>> in hci_alloc_dev_priv(). >>> >>> Signed-off-by: Wei Yongjun <weiyongjun1@xxxxxxxxxx> >>> >>> diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c >>> index 8a47a3017d61..42410f568e90 100644 >>> --- a/net/bluetooth/hci_core.c >>> +++ b/net/bluetooth/hci_core.c >>> @@ -3876,6 +3876,11 @@ struct hci_dev *hci_alloc_dev_priv(int sizeof_priv) >>> INIT_DELAYED_WORK(&hdev->cmd_timer, hci_cmd_timeout); >>> INIT_DELAYED_WORK(&hdev->ncmd_timer, hci_ncmd_timeout); >>> >>> + /* We need to set HCI_UNREGISTER flag to correctly release >>> + * the device in hci_free_dev() >>> + */ >>> + hci_dev_set_flag(hdev, HCI_UNREGISTER); >>> + >> >> I can see the point in the bug report, but I don’t see that the fix is correct. Can you prove that this fix is correct when hci_register_dev is actually called. > > I also wonder where is the actual check for HCI_UNREGISTER that the > commit description says prevents the kfree? hci_free_dev itself just > calls put_device, so perhaps it is actually talking about the check in > bt_host_release, anyway in for this to work the HCI_UNREGISTER would > have to be cleared by hci_register_dev otherwise the likes of > hci_dev_do_open don't work as it checks if HCI_UNREGISTER had been > called. > > We also would need to check if it is safe to call hci_release_dev if > the workqueues, etc, had not been initialized yet, or perhaps don't > really use HCI_UNREGISTER and just do something like this: > > diff --git a/net/bluetooth/hci_sysfs.c b/net/bluetooth/hci_sysfs.c > index 7827639ecf5c..81c50b47183f 100644 > --- a/net/bluetooth/hci_sysfs.c > +++ b/net/bluetooth/hci_sysfs.c > @@ -86,6 +86,9 @@ static void bt_host_release(struct device *dev) > > if (hci_dev_test_flag(hdev, HCI_UNREGISTER)) > hci_release_dev(hdev); > + else > + kfree(hdev); > + > module_put(THIS_MODULE); > > If this doesn't fix all the leaks that probably means part of the > hci_release_dev still needs to be executed which can probably be done > by having the check for HCI_UNREGISTER around the code that does > actually depend on hci_register_dev. what we really need to do is move towards devm integration so that all allocation are tied to the driver model. However this might need a cleaner struct device integration. Regards Marcel
