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 <[email protected]>
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);
+
hci_request_setup(hdev);
hci_init_sysfs(hdev);
--
2.25.1
Hi Wei,
> 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 <[email protected]>
>
> 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.
Regards
Marcel
Hi Wei, Marcel,
On Tue, Oct 12, 2021 at 8:54 AM Marcel Holtmann <[email protected]> wrote:
>
> Hi Wei,
>
> > 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 <[email protected]>
> >
> > 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.
--
Luiz Augusto von Dentz
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 <[email protected]>
>>>
>>> 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
Hi Luiz, Marcel
> 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 <[email protected]>
>>>>
>>>> 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.
>
I have tested with your fix with fault injection, and all the
memory leak is gone.
Regards,
Wei Yongjun