On 01. 04. 2023. 11:23, Greg KH wrote:
> On Sat, Apr 01, 2023 at 11:18:19AM +0200, Greg KH wrote:
>> On Sat, Apr 01, 2023 at 08:33:36AM +0200, Greg KH wrote:
>>> On Sat, Apr 01, 2023 at 08:28:07AM +0200, Greg KH wrote:
>>>> On Sat, Apr 01, 2023 at 08:23:26AM +0200, Mirsad Goran Todorovac wrote:
>>>>>> This patch is implying that anyone who calls "dev_set_name()" also has
>>>>>> to do this hack, which shouldn't be the case at all.
>>>>>>
>>>>>> thanks,
>>>>>>
>>>>>> greg k-h
>>>>>
>>>>> This is my best guess. Unless there is dev_free_name() or kobject_free_name(), I don't
>>>>> see a more sensible way to patch this up.
>>>>
>>>> In sleeping on this, I think this has to move to the driver core. I
>>>> don't understand why we haven't seen this before, except maybe no one
>>>> has really noticed before (i.e. we haven't had good leak detection tools
>>>> that run with removable devices?)
>>>>
>>>> Anyway, let me see if I can come up with something this weekend, give me
>>>> a chance...
>>>
>>> Wait, no, this already should be handled by the kobject core, look at
>>> kobject_cleanup(), at the bottom. So your change should be merely
>>> duplicating the logic there that already runs when the struct device is
>>> freed, right?
>>>
>>> So I don't understand why your change works, odd. I need more coffee...
>>
>> I think you got half of the change correctly. This init code is a maze
>> of twisty passages, let me take your patch and tweak it a bit into
>> something that I think should work. This looks to be only a memstick
>> issue, not a driver core issue (which makes me feel better.)
>
> Oops, forgot the patch. Can you try this change here and let me know if
> that solves the problem or not? I have compile-tested it only, so I
> have no idea if it works.
>
> If this does work, I'll make up a "real" function to replace the
> horrible dev.kobj.name mess that a driver would have to do here as it
> shouldn't be required that a driver author knows the internals of the
> driver core that well...
>
> thanks,
>
> greg k-h
>
> --------------------
>
>
> diff --git a/drivers/memstick/core/memstick.c b/drivers/memstick/core/memstick.c
> index bf7667845459..bbfaf6536903 100644
> --- a/drivers/memstick/core/memstick.c
> +++ b/drivers/memstick/core/memstick.c
> @@ -410,6 +410,7 @@ static struct memstick_dev *memstick_alloc_card(struct memstick_host *host)
> return card;
> err_out:
> host->card = old_card;
> + kfree_const(card->dev.kobj.name);
> kfree(card);
> return NULL;
> }
> @@ -468,8 +469,10 @@ static void memstick_check(struct work_struct *work)
> put_device(&card->dev);
> host->card = NULL;
> }
> - } else
> + } else {
> + kfree_const(card->dev.kobj.name);
> kfree(card);
> + }
> }
>
> out_power_off:
I thought of this version, but I am not sure about tracking the device_register() and
device_unregister() calls?
put_device() calls put_kobject() which frees the const char *kobj.name ...
I thought how host cannot just be kfree()d when host->card is still allocated.
And it is a pointer. That also seems to me like a bug :-/
Kind regards,
Mirsad
---
diff --git a/drivers/memstick/core/memstick.c b/drivers/memstick/core/memstick.c
index bf7667845459..46c7bda9715d 100644
--- a/drivers/memstick/core/memstick.c
+++ b/drivers/memstick/core/memstick.c
@@ -179,6 +179,8 @@ static void memstick_free(struct device *dev)
{
struct memstick_host *host = container_of(dev, struct memstick_host,
dev);
+ if (host->card && host->card->dev)
+ put_device(&host->card->dev);
kfree(host);
}
@@ -410,7 +412,7 @@ static struct memstick_dev *memstick_alloc_card(struct memstick_host *host)
return card;
err_out:
host->card = old_card;
- kfree(card);
+ put_device(&card->dev);
return NULL;
}
@@ -468,8 +470,9 @@ static void memstick_check(struct work_struct *work)
put_device(&card->dev);
host->card = NULL;
}
- } else
- kfree(card);
+ } else {
+ put_device(&card->dev);
+ }
}
out_power_off:
--
Mirsad Goran Todorovac
Sistem inženjer
Grafički fakultet | Akademija likovnih umjetnosti
Sveučilište u Zagrebu
System engineer
Faculty of Graphic Arts | Academy of Fine Arts
University of Zagreb, Republic of Croatia
The European Union
"I see something approaching fast ... Will it be friends with me?"
