| From foo@baz Mon Jan 18 21:18:36 PST 2016 |
| From: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> |
| Date: Fri, 4 Dec 2015 01:45:40 +0300 |
| Subject: sh_eth: fix kernel oops in skb_put() |
| Status: RO |
| Content-Length: 2307 |
| Lines: 61 |
| |
| From: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> |
| |
| [ Upstream commit 248be83dcb3feb3f6332eb3d010a016402138484 ] |
| |
| In a low memory situation the following kernel oops occurs: |
| |
| Unable to handle kernel NULL pointer dereference at virtual address 00000050 |
| pgd = 8490c000 |
| [00000050] *pgd=4651e831, *pte=00000000, *ppte=00000000 |
| 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 <yashi@atmark-techno.com> |
| Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| drivers/net/ethernet/renesas/sh_eth.c | 4 ++-- |
| 1 file changed, 2 insertions(+), 2 deletions(-) |
| |
| --- a/drivers/net/ethernet/renesas/sh_eth.c |
| +++ b/drivers/net/ethernet/renesas/sh_eth.c |
| @@ -1421,6 +1421,7 @@ static int sh_eth_rx(struct net_device * |
| desc_status >>= 16; |
| #endif |
| |
| + skb = mdp->rx_skbuff[entry]; |
| if (desc_status & (RD_RFS1 | RD_RFS2 | RD_RFS3 | RD_RFS4 | |
| RD_RFS5 | RD_RFS6 | RD_RFS10)) { |
| ndev->stats.rx_errors++; |
| @@ -1436,12 +1437,11 @@ static int sh_eth_rx(struct net_device * |
| ndev->stats.rx_missed_errors++; |
| if (desc_status & RD_RFS10) |
| ndev->stats.rx_over_errors++; |
| - } else { |
| + } else if (skb) { |
| if (!mdp->cd->hw_swap) |
| sh_eth_soft_swap( |
| phys_to_virt(ALIGN(rxdesc->addr, 4)), |
| pkt_len + 2); |
| - skb = mdp->rx_skbuff[entry]; |
| mdp->rx_skbuff[entry] = NULL; |
| if (mdp->cd->rpadir) |
| skb_reserve(skb, NET_IP_ALIGN); |