At 2023-02-03 13:25:45, "Christophe JAILLET" <christophe.jaillet@xxxxxxxxxx> wrote:
>Le 03/02/2023 à 05:16, Zheng Wang a écrit :
>> Although the usb_alloc_urb uses GFP_ATOMIC, tring to make sure the memory
>> allocated not to be NULL. But in some low-memory situation, it's still
>> possible to return NULL. It'll pass urb as argument in
>> usb_fill_bulk_urb, which will finally lead to a NULL pointer dereference.
>>
>> Fix it by adding additional check.
>>
>> Note that, as a bug found by static analysis, it can be a false
>> positive or hard to trigger.
>>
>> Fixes: 68d57a07bfe5 ("wireless: add plfxlc driver for pureLiFi X, XL, XC devices")
>>
>> Signed-off-by: Zheng Wang <zyytlz.wz@xxxxxxx>
>> ---
>> drivers/net/wireless/purelifi/plfxlc/usb.c | 7 +++++++
>> 1 file changed, 7 insertions(+)
>>
>> diff --git a/drivers/net/wireless/purelifi/plfxlc/usb.c b/drivers/net/wireless/purelifi/plfxlc/usb.c
>> index 76d0a778636a..ac149aa64908 100644
>> --- a/drivers/net/wireless/purelifi/plfxlc/usb.c
>> +++ b/drivers/net/wireless/purelifi/plfxlc/usb.c
>> @@ -496,10 +496,17 @@ int plfxlc_usb_wreq_async(struct plfxlc_usb *usb, const u8 *buffer,
>> struct urb *urb = usb_alloc_urb(0, GFP_ATOMIC);
>> int r;
>>
>> + if (!urb) {
>> + r = -ENOMEM;
>> + kfree(urb);
>
>Hi,
>why kfree() in such a case?
Hello CJ,
Thanks for pointing that out. Kfree is unnecessary in such case, we can just return.
Regards,
Zheng Wang
>
>> + goto out;
>> + }
>> usb_fill_bulk_urb(urb, udev, usb_sndbulkpipe(udev, EP_DATA_OUT),
>> (void *)buffer, buffer_len, complete_fn, context);
>>
>> r = usb_submit_urb(urb, GFP_ATOMIC);
>> +
>> +out:
>> if (r)
>> dev_err(&udev->dev, "Async write submit failed (%d)\n", r);
>>
