| Message ID | 20221104033945.1120044-2-yangyingliang@huawei.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 5822e8cc84ee37338ab0bdc3124f6eec04dc232d |
| Headers | show |
| Series | MIPS: fix possible memory leak while module exiting | expand |
On Fri, Nov 04, 2022 at 11:39:44AM +0800, Yang Yingliang wrote: > Afer commit 1fa5ae857bb1 ("driver core: get rid of struct device's > bus_id string array"), the name of device is allocated dynamically, > it need be freed when module exiting, call put_device() to give up > reference, so that it can be freed in kobject_cleanup() when the > refcount hit to 0. The vpe_device is static, so remove kfree() from > vpe_device_release(). > > Fixes: 1fa5ae857bb1 ("driver core: get rid of struct device's bus_id string array") > Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> > --- > arch/mips/kernel/vpe-mt.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/mips/kernel/vpe-mt.c b/arch/mips/kernel/vpe-mt.c > index bad6b0891b2b..84a82b551ec3 100644 > --- a/arch/mips/kernel/vpe-mt.c > +++ b/arch/mips/kernel/vpe-mt.c > @@ -313,7 +313,6 @@ ATTRIBUTE_GROUPS(vpe); > > static void vpe_device_release(struct device *cd) > { > - kfree(cd); > } as this is empty now, we can IMHO remove the function completly. Same for the other patch in this series. Thomas.
Hi, On 2022/11/22 19:21, Thomas Bogendoerfer wrote: > On Fri, Nov 04, 2022 at 11:39:44AM +0800, Yang Yingliang wrote: >> Afer commit 1fa5ae857bb1 ("driver core: get rid of struct device's >> bus_id string array"), the name of device is allocated dynamically, >> it need be freed when module exiting, call put_device() to give up >> reference, so that it can be freed in kobject_cleanup() when the >> refcount hit to 0. The vpe_device is static, so remove kfree() from >> vpe_device_release(). >> >> Fixes: 1fa5ae857bb1 ("driver core: get rid of struct device's bus_id string array") >> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> >> --- >> arch/mips/kernel/vpe-mt.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/arch/mips/kernel/vpe-mt.c b/arch/mips/kernel/vpe-mt.c >> index bad6b0891b2b..84a82b551ec3 100644 >> --- a/arch/mips/kernel/vpe-mt.c >> +++ b/arch/mips/kernel/vpe-mt.c >> @@ -313,7 +313,6 @@ ATTRIBUTE_GROUPS(vpe); >> >> static void vpe_device_release(struct device *cd) >> { >> - kfree(cd); >> } > as this is empty now, we can IMHO remove the function completly. Same > for the other patch in this series. It can not be removed, or it will cause WARNING in device_release() when calling put_device()/device_unregister(). static void device_release(struct kobject *kobj) { ... if (dev->release) dev->release(dev); else if (dev->type && dev->type->release) dev->type->release(dev); else if (dev->class && dev->class->dev_release) dev->class->dev_release(dev); else WARN(1, KERN_ERR "Device '%s' does not have a release() function, it is broken and must be fixed. See Documentation/core-api/kobject.rst.\n", dev_name(dev)); // WANING here ... } Thanks, Yang > > Thomas. >
On Tue, Nov 22, 2022 at 07:41:26PM +0800, Yang Yingliang wrote: > Hi, > > On 2022/11/22 19:21, Thomas Bogendoerfer wrote: > > On Fri, Nov 04, 2022 at 11:39:44AM +0800, Yang Yingliang wrote: > > > Afer commit 1fa5ae857bb1 ("driver core: get rid of struct device's > > > bus_id string array"), the name of device is allocated dynamically, > > > it need be freed when module exiting, call put_device() to give up > > > reference, so that it can be freed in kobject_cleanup() when the > > > refcount hit to 0. The vpe_device is static, so remove kfree() from > > > vpe_device_release(). > > > > > > Fixes: 1fa5ae857bb1 ("driver core: get rid of struct device's bus_id string array") > > > Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> > > > --- > > > arch/mips/kernel/vpe-mt.c | 4 ++-- > > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > > > diff --git a/arch/mips/kernel/vpe-mt.c b/arch/mips/kernel/vpe-mt.c > > > index bad6b0891b2b..84a82b551ec3 100644 > > > --- a/arch/mips/kernel/vpe-mt.c > > > +++ b/arch/mips/kernel/vpe-mt.c > > > @@ -313,7 +313,6 @@ ATTRIBUTE_GROUPS(vpe); > > > static void vpe_device_release(struct device *cd) > > > { > > > - kfree(cd); > > > } > > as this is empty now, we can IMHO remove the function completly. Same > > for the other patch in this series. > It can not be removed, or it will cause WARNING in device_release() when > calling > put_device()/device_unregister(). > > static void device_release(struct kobject *kobj) > { > ... > > if (dev->release) > dev->release(dev); > else if (dev->type && dev->type->release) > dev->type->release(dev); > else if (dev->class && dev->class->dev_release) > dev->class->dev_release(dev); > else > WARN(1, KERN_ERR "Device '%s' does not have a release() > function, it is broken and must be fixed. See > Documentation/core-api/kobject.rst.\n", > dev_name(dev)); // WANING here you are right, thank you for looking into that, Thomas.
diff --git a/arch/mips/kernel/vpe-mt.c b/arch/mips/kernel/vpe-mt.c index bad6b0891b2b..84a82b551ec3 100644 --- a/arch/mips/kernel/vpe-mt.c +++ b/arch/mips/kernel/vpe-mt.c @@ -313,7 +313,6 @@ ATTRIBUTE_GROUPS(vpe); static void vpe_device_release(struct device *cd) { - kfree(cd); } static struct class vpe_class = { @@ -497,6 +496,7 @@ int __init vpe_module_init(void) device_del(&vpe_device); out_class: + put_device(&vpe_device); class_unregister(&vpe_class); out_chrdev: @@ -509,7 +509,7 @@ void __exit vpe_module_exit(void) { struct vpe *v, *n; - device_del(&vpe_device); + device_unregister(&vpe_device); class_unregister(&vpe_class); unregister_chrdev(major, VPE_MODULE_NAME);
Afer commit 1fa5ae857bb1 ("driver core: get rid of struct device's bus_id string array"), the name of device is allocated dynamically, it need be freed when module exiting, call put_device() to give up reference, so that it can be freed in kobject_cleanup() when the refcount hit to 0. The vpe_device is static, so remove kfree() from vpe_device_release(). Fixes: 1fa5ae857bb1 ("driver core: get rid of struct device's bus_id string array") Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- arch/mips/kernel/vpe-mt.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)