| Message ID | 20211012075634.8041-1-weiyongjun1@huawei.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Bluetooth: Fix memory leak of hci device | expand |
| Context | Check | Description |
|---|---|---|
| tedd_an/checkpatch | success | Checkpatch PASS |
| tedd_an/gitlint | success | Gitlint PASS |
| tedd_an/buildkernel | success | Build Kernel PASS |
| tedd_an/testrunnersetup | success | Test Runner Setup PASS |
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 <weiyongjun1@huawei.com> > > 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 <marcel@holtmann.org> 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 <weiyongjun1@huawei.com> > > > > 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.
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@huawei.com> >>> >>> 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 <weiyongjun1@huawei.com> >>>> >>>> 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
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);
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@huawei.com>