On 08/11/14 11:55, Nick Krause wrote: > On Mon, Aug 11, 2014 at 2:45 PM, Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote: >> On 08/11/14 11:26, Nick Krause wrote: >>> On Mon, Aug 11, 2014 at 2:07 PM, Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote: >>>> On 08/11/14 11:04, Nick Krause wrote: >>>>> On Mon, Aug 11, 2014 at 2:02 PM, Nicholas Krause <xerofoify@xxxxxxxxx> wrote: >>>>>> I am fixing the bug entry , https://bugzilla.kernel.org/show_bug.cgi?id=60461. >>>>>> This entry states that we are not checking the skb allocated in fw_download_code >>>>>> and after checking I fixed it to check for the NULL value before using the allocate >>>>>> skb. >>>>>> >>>>>> Signed-off-by: Nicholas Krause <xerofoify@xxxxxxxxx> >>>>>> --- >>>>>> drivers/staging/rtl8192e/rtl8192e/r8192E_firmware.c | 14 ++++++++------ >>>>>> 1 file changed, 8 insertions(+), 6 deletions(-) >>>>>> >>>>>> diff --git a/drivers/staging/rtl8192e/rtl8192e/r8192E_firmware.c b/drivers/staging/rtl8192e/rtl8192e/r8192E_firmware.c >>>>>> index 1a95d1f..0a4c926 100644 >>>>>> --- a/drivers/staging/rtl8192e/rtl8192e/r8192E_firmware.c >>>>>> +++ b/drivers/staging/rtl8192e/rtl8192e/r8192E_firmware.c >>>>>> @@ -60,13 +60,15 @@ static bool fw_download_code(struct net_device *dev, u8 *code_virtual_address, >>>>>> >>>>>> } >>>>>> >>>>>> - skb = dev_alloc_skb(frag_length + 4); >>>>>> - memcpy((unsigned char *)(skb->cb), &dev, sizeof(dev)); >>>>>> - tcb_desc = (struct cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE); >>>>>> - tcb_desc->queue_index = TXCMD_QUEUE; >>>>>> - tcb_desc->bCmdOrInit = DESC_PACKET_TYPE_INIT; >>>>>> - tcb_desc->bLastIniPkt = bLastIniPkt; >>>>>> >>>>>> + skb = dev_alloc_skb(frag_length + 4); >>>>>> + if (skb) { >>>>>> + memcpy((unsigned char *)(skb->cb), &dev, sizeof(dev)); >>>>>> + tcb_desc = (struct cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE); >>>>>> + tcb_desc->queue_index = TXCMD_QUEUE; >>>>>> + tcb_desc->bCmdOrInit = DESC_PACKET_TYPE_INIT; >>>>>> + tcb_desc->bLastIniPkt = bLastIniPkt; >>>>>> + } >>>> >>>> and what happens here (below) if skb is NULL? >> >> Nick, >> I'm asking if you have completely fixed the bug or only partially fixed it. >> The answer is that the patch is only a partial fix. If skb is NULL, there >> is still a problem in the statement below here. The kernel will oops on >> that reference to skb, which is NULL. >> >>>> >>>>>> seg_ptr = skb->data; >>>>>> for (i = 0; i < frag_length; i += 4) { >>>>>> *seg_ptr++ = ((i+0) < frag_length) ? >>>>>> -- >>>>>> 1.9.1 >>>>>> >>>>> And I did check it against Linus's tree to make sure it applies , just >>>>> to let you known. >>>>> Nick >>>> >>>> >>>> -- >>>> ~Randy >>> Sorry Randy. >>> I may be mis reading this, but are you asking me to write a different >>> commit message or is this patch just another bad patch in my series of >>> bad patches? >> >> >> -- >> ~Randy > > Randy , > Thanks for the catch :). Would you recommend just putting it in the if > statement I created or create a second if statement for > code readability. Neither one of those choices. I suggest that the code immediately check for skb == NULL and return 0 (or false) if it is NULL. Then the code below that check won't need to be changed at all. -- ~Randy _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
