2018-06-22 2:23 GMT+01:00 Jaejoong Kim <climbbb.kim@xxxxxxxxx>:
> Hi Michal,
>
> Could you check this patch?
Sorry about long delay, I haven’t settled in my new place yet (which
is also why I’m using Gmail).
> 2018년 6월 14일 (목) 오후 11:55, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>님이 작성:
>>
>> On Thu, 14 Jun 2018, Jaejoong Kim wrote:
>>
>> > The reference count is initialized in fsg_alloc_inst(). So if
>> > fsg_alloc_inst() fails, we need to add kref_put() to free an
>> > allocated memory.
>> >
>> > Signed-off-by: Jaejoong Kim <climbbb.kim@xxxxxxxxx>
>> > ---
>> > drivers/usb/gadget/function/f_mass_storage.c | 1 +
>> > 1 file changed, 1 insertion(+)
>> >
>> > diff --git a/drivers/usb/gadget/function/f_mass_storage.c
>> > b/drivers/usb/gadget/function/f_mass_storage.c
>> > index acecd13..83eeafe 100644
>> > --- a/drivers/usb/gadget/function/f_mass_storage.c
>> > +++ b/drivers/usb/gadget/function/f_mass_storage.c
>> > @@ -3392,6 +3392,7 @@ static struct usb_function_instance
>> > *fsg_alloc_inst(void)
>> > release_buffers:
>> > fsg_common_free_buffers(opts->common);
>> > release_opts:
>> > + fsg_common_put(opts->common);
>> > kfree(opts);
>> > return ERR_PTR(rc);
>> > }
This looks legitimate but in the current form could lead to dereference
of an uninitialized pointer. Furthermore, calling free_buffers is no longer
necessary. To solve the dereference problem, add
commo->buffhds = NULL;
to fsg_common_setup (or add memset(common, 0, sizeof *common)
to the path without kzalloc). With that, the the two error handling labels
can be collapsed to one:
error:
fsg_common_put(opts->common);
kfree(opts);
return ERR_PTR(rc);
>>
>> I'm not at all sure about this. Michal is a lot more familiar with
>> this part of the code than I am.
>>
>> It looks like there's a memory leak if fsg_common_release() isn't
>> called here. But if it is called at this point, it might not behave
>> properly.
>>
>> Alan Stern
>>
>
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