From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Date: Mon, 14 Dec 2015 21:24:47 +0000 Subject: Re: [PATCH v3] sh_eth: fix kernel oops in skb_put() Message-Id: <20151214.162447.1100345678412142334.davem@davemloft.net> List-Id: References: <1498048.4g9dLWgJuk@wasted.cogentembedded.com> <20151205.174648.1064779484509050839.davem@davemloft.net> <566C3A99.2000103@cogentembedded.com> In-Reply-To: <566C3A99.2000103@cogentembedded.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: sergei.shtylyov@cogentembedded.com Cc: netdev@vger.kernel.org, yashi@atmark-techno.com, linux-sh@vger.kernel.org From: Sergei Shtylyov Date: Sat, 12 Dec 2015 18:17:45 +0300 > Hello. > > On 12/6/2015 1:46 AM, David Miller wrote: > >>> In a low memory situation the following kernel oops occurs: >>> >>> Unable to handle kernel NULL pointer dereference at virtual address >>> 00000050 >>> pgd = 8490c000 >>> [00000050] *pgdF51e831, *pte000000, *ppte000000 >>> Internal error: Oops: 17 [#1] PREEMPT ARM >>> Modules linked in: >>> CPU: 0 Not tainted (3.4-at16 #9) >>> PC is at skb_put+0x10/0x98 >>> LR is at sh_eth_poll+0x2c8/0xa10 >>> pc : [<8035f780>] lr : [<8028bf50>] psr: 60000113 >>> sp : 84eb1a90 ip : 84eb1ac8 fp : 84eb1ac4 >>> r10: 0000003f r9 : 000005ea r8 : 00000000 >>> r7 : 00000000 r6 : 940453b0 r5 : 00030000 r4 : 9381b180 >>> r3 : 00000000 r2 : 00000000 r1 : 000005ea r0 : 00000000 >>> Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user >>> Control: 10c53c7d Table: 4248c059 DAC: 00000015 >>> Process klogd (pid: 2046, stack limit = 0x84eb02e8) >>> [...] >>> >>> This is because netdev_alloc_skb() fails and 'mdp->rx_skbuff[entry]' >>> is left >>> NULL but sh_eth_rx() later uses it without checking. Add such >>> check... >>> >>> Reported-by: Yasushi SHOJI >>> Signed-off-by: Sergei Shtylyov > >> Applied. > > Could you also queue this for the stable kernels? Done.