Re: [PATCH] [SCSI] iscsi_boot_sysfs: Fix a memory leak in iscsi_boot_destroy_kset()

[Mike Christie <michaelc@cs.wisc.edu>]

On 12/10/13 8:11 AM, Konrad Rzeszutek Wilk wrote:
> Ethan Zhao <ethan.kernel@gmail.com> wrote:
>> Konrad,
>>
>> boot_kset was allocated when module loaded by
>> ibft_init()
>>   iscsi_boot_create_kset()
>>      kzalloc()
>>
>> but wasn't freed when module unloaded by
>> ibft_exit()
>>    ibft_cleanup()
>>      iscsi_boot_destroy_kset()
>>
>> Thanks,
>> Ethan
>>
>> On Tue, Dec 10, 2013 at 5:30 AM, Konrad Rzeszutek Wilk
>> <konrad.wilk@oracle.com> wrote:
>>> On Mon, Dec 09, 2013 at 05:37:11PM +0800, Ethan Zhao wrote:
>>>> From: "Ethan Zhao" <ethan.kernel@gmail.com>
>>>>
>>>> Load and unload iscsi_ibft module will cause kernel memory leak, fix
>> it
>>>> in scsi/iscsi_boot_sysfs.c iscsi_boot_destroy_kset().
>>>>
>>>
>>> Is there a stack trace?
>>>> Signed-off-by: Ethan Zhao <ethan.kernel@gmail.com>
>>>> ---
>>>>   drivers/scsi/iscsi_boot_sysfs.c | 1 +
>>>>   1 file changed, 1 insertion(+)
>>>>
>>>> diff --git a/drivers/scsi/iscsi_boot_sysfs.c
>> b/drivers/scsi/iscsi_boot_sysfs.c
>>>> index 14c1c8f..680bf6f 100644
>>>> --- a/drivers/scsi/iscsi_boot_sysfs.c
>>>> +++ b/drivers/scsi/iscsi_boot_sysfs.c
>>>> @@ -490,5 +490,6 @@ void iscsi_boot_destroy_kset(struct
>> iscsi_boot_kset *boot_kset)
>>>>                iscsi_boot_remove_kobj(boot_kobj);
>>>>
>>>>        kset_unregister(boot_kset->kset);
>>>> +     kfree(boot_kset);
>>>>   }
>>>>   EXPORT_SYMBOL_GPL(iscsi_boot_destroy_kset);
>>>> --
>>>> 1.8.3.4 (Apple Git-47)
>>>>
>
> Right. In the past we did not do that b/c certain drivers (like broadcom) would allocate on the kset their name and try to free (the driver would after freeing the ibft). So you would end up with this patch a double free ( and it might be fixed by now but I can't recall).
>

Do you mean the name string that is passed into kset_create_and_add? If 
so that should not happen now. There does not seem to be any user 
freeing that string.

There used to be bug where at the initiator/target/ethernet level there 
was a double free because iscsi_boot_sysfs and be2iscsi were both 
freeing the struct associated with the initiator/target/ethernet. That 
is fixed in f457a46f179df41b0f6d80dee33b6e629945f276.