From mboxrd@z Thu Jan 1 00:00:00 1970 From: Larry Finger Subject: Re: [BUG] rtl8192se: panic accessing unmapped memory in skb Date: Mon, 22 Dec 2014 11:43:38 -0600 Message-ID: <5498584A.6080204@lwfinger.net> References: <20141221172516.GA12784@zzz> <5497516A.2020400@lwfinger.net> <20141221234714.GA30675@zzz> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Eric Biggers Return-path: In-Reply-To: <20141221234714.GA30675@zzz> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 12/21/2014 05:47 PM, Eric Biggers wrote: > Hi, > > To get your patched version to work at all I had to update > _rtl_pci_init_rx_ring() to account for new return value of > _rtl_pci_init_one_rxdesc(). I will let you know if anything shows up in the > kernel log, but I expect this is a highly sporadic problem. The system has 4 GB > of memory, and I used the 3.18 kernel for 10 days prior to the panic with no > issues. The panic occurred while upgrading system packages, so it's possible > jhat the system was experiencing memory pressure. > > I upgraded from 3.17 to 3.18 on Dec 8, so I've actually only had since then to > notice any bugs that may have been introduced since 3.17. > > It does appear there were changes made to pci.c between 3.17 and 3.18. It > appears the 3.17 code will drop the incoming packet if a new skb can't be > allocated, whereas the 3.18 code assumes a new skb can always be allocated. The > 3.17 behavior seems more logical to me. I don't know how either of these > behaviors compare to other networking drivers, however. Sorry about missing the necessary changes in the rest of the driver. That is what I get for only compile testing. I reviewed the 3.17 => 3.18 changes and found the difference in the logic that you noticed, and I missed earlier. As a result, I need to push this change for 3.19 with the notation for updating of 3.18. You have probably received this patch already. As it needs to be backported, I decided to forgo changing the return value of _rtl_pci_init_one_rxdesc(). That change should be made, but there is no emergency there. Thanks, Larry