Re: [PATCH] vme: remove unneeded kfree
On Thu, 2018-09-06 at 22:04 -0700, Linus Torvalds wrote:
> On Thu, Sep 6, 2018 at 1:51 AM Ding Xiang
> wrote:
> >
> > put_device will call vme_dev_release to free vdev, kfree is
> > unnecessary here.
>
> That does seem to be the case. I think "unnecessary" is overly kind,
> it does seem to be a double free.
>
> Looks like the issue was introduced back in 2013 by commit
> def1820d25fa ("vme: add missing put_device() after device_register()
> fails").
>
> It seems you should *either* kfree() the vdev, _or_ do put_device(),
> but doing both seems wrong.
>
> I presume the device_register() has never failed, and this being
> vme-only I'm guessing there isn't a vibrant testing community.
>
I think that is also overly kind :-)
I currently lack access to suitable hardware to test fully myself and I
need to find some time to (re)implement some automated testing, after I
lost access to the bits I had when I left a previous employer. That and
see if I can get access to some hardware again...
Manohar, do you still have access/interest in the VME stuff? You've
been very quiet for a long time now.
Martyn
Re: [PATCH] vme: remove unneeded kfree
On Thu, 2018-09-06 at 22:04 -0700, Linus Torvalds wrote:
> On Thu, Sep 6, 2018 at 1:51 AM Ding Xiang
> wrote:
> >
> > put_device will call vme_dev_release to free vdev, kfree is
> > unnecessary here.
>
> That does seem to be the case. I think "unnecessary" is overly kind,
> it does seem to be a double free.
>
> Looks like the issue was introduced back in 2013 by commit
> def1820d25fa ("vme: add missing put_device() after device_register()
> fails").
>
> It seems you should *either* kfree() the vdev, _or_ do put_device(),
> but doing both seems wrong.
>
> I presume the device_register() has never failed, and this being
> vme-only I'm guessing there isn't a vibrant testing community.
>
I think that is also overly kind :-)
I currently lack access to suitable hardware to test fully myself and I
need to find some time to (re)implement some automated testing, after I
lost access to the bits I had when I left a previous employer. That and
see if I can get access to some hardware again...
Manohar, do you still have access/interest in the VME stuff? You've
been very quiet for a long time now.
Martyn
Re: [PATCH] vme: remove unneeded kfree
On Thu, Sep 06, 2018 at 10:04:49PM -0700, Linus Torvalds wrote:
> On Thu, Sep 6, 2018 at 1:51 AM Ding Xiang
> wrote:
> >
> > put_device will call vme_dev_release to free vdev, kfree is
> > unnecessary here.
>
> That does seem to be the case. I think "unnecessary" is overly kind,
> it does seem to be a double free.
>
> Looks like the issue was introduced back in 2013 by commit
> def1820d25fa ("vme: add missing put_device() after device_register()
> fails").
>
> It seems you should *either* kfree() the vdev, _or_ do put_device(),
> but doing both seems wrong.
You should only ever call put_device() after you have created the
structure, the documentation should say that somewhere...
> I presume the device_register() has never failed, and this being
> vme-only I'm guessing there isn't a vibrant testing community.
>
> Greg?
It's the correct fix, I'll queue it up soon, thanks.
greg k-h
Re: [PATCH] vme: remove unneeded kfree
On Thu, Sep 06, 2018 at 10:04:49PM -0700, Linus Torvalds wrote:
> On Thu, Sep 6, 2018 at 1:51 AM Ding Xiang
> wrote:
> >
> > put_device will call vme_dev_release to free vdev, kfree is
> > unnecessary here.
>
> That does seem to be the case. I think "unnecessary" is overly kind,
> it does seem to be a double free.
>
> Looks like the issue was introduced back in 2013 by commit
> def1820d25fa ("vme: add missing put_device() after device_register()
> fails").
>
> It seems you should *either* kfree() the vdev, _or_ do put_device(),
> but doing both seems wrong.
You should only ever call put_device() after you have created the
structure, the documentation should say that somewhere...
> I presume the device_register() has never failed, and this being
> vme-only I'm guessing there isn't a vibrant testing community.
>
> Greg?
It's the correct fix, I'll queue it up soon, thanks.
greg k-h
Re: [PATCH] vme: remove unneeded kfree
On Thu, Sep 6, 2018 at 1:51 AM Ding Xiang
wrote:
>
> put_device will call vme_dev_release to free vdev, kfree is
> unnecessary here.
That does seem to be the case. I think "unnecessary" is overly kind,
it does seem to be a double free.
Looks like the issue was introduced back in 2013 by commit
def1820d25fa ("vme: add missing put_device() after device_register()
fails").
It seems you should *either* kfree() the vdev, _or_ do put_device(),
but doing both seems wrong.
I presume the device_register() has never failed, and this being
vme-only I'm guessing there isn't a vibrant testing community.
Greg?
Linus
Re: [PATCH] vme: remove unneeded kfree
On Thu, Sep 6, 2018 at 1:51 AM Ding Xiang
wrote:
>
> put_device will call vme_dev_release to free vdev, kfree is
> unnecessary here.
That does seem to be the case. I think "unnecessary" is overly kind,
it does seem to be a double free.
Looks like the issue was introduced back in 2013 by commit
def1820d25fa ("vme: add missing put_device() after device_register()
fails").
It seems you should *either* kfree() the vdev, _or_ do put_device(),
but doing both seems wrong.
I presume the device_register() has never failed, and this being
vme-only I'm guessing there isn't a vibrant testing community.
Greg?
Linus
[PATCH] vme: remove unneeded kfree
put_device will call vme_dev_release to free vdev, kfree is
unnecessary here.
Signed-off-by: Ding Xiang
---
drivers/vme/vme.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/vme/vme.c b/drivers/vme/vme.c
index 92500f6..520a5f9 100644
--- a/drivers/vme/vme.c
+++ b/drivers/vme/vme.c
@@ -1890,7 +1890,6 @@ static int __vme_register_driver_bus(struct vme_driver
*drv,
err_reg:
put_device(>dev);
- kfree(vdev);
err_devalloc:
list_for_each_entry_safe(vdev, tmp, >devices, drv_list) {
list_del(>drv_list);
--
1.9.1
[PATCH] vme: remove unneeded kfree
put_device will call vme_dev_release to free vdev, kfree is
unnecessary here.
Signed-off-by: Ding Xiang
---
drivers/vme/vme.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/vme/vme.c b/drivers/vme/vme.c
index 92500f6..520a5f9 100644
--- a/drivers/vme/vme.c
+++ b/drivers/vme/vme.c
@@ -1890,7 +1890,6 @@ static int __vme_register_driver_bus(struct vme_driver
*drv,
err_reg:
put_device(>dev);
- kfree(vdev);
err_devalloc:
list_for_each_entry_safe(vdev, tmp, >devices, drv_list) {
list_del(>drv_list);
--
1.9.1
