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authorSergei Shtylyov <sergei.shtylyov@cogentembedded.com>2015-12-04 01:45:40 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-01-22 20:54:13 -0800
commit8fa4abd57ad4ef9b2ff9beda2eb29368ae10ae9e (patch)
tree723cfce1abb8956751aad79a5ce073eb78a89df0
parentbc8f79b522b57ca79a676615003d85b08162ff5a (diff)
sh_eth: fix kernel oops in skb_put()
[ 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>
-rw-r--r--drivers/net/ethernet/renesas/sh_eth.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c
index 7fb244f565b2..13463c4acc86 100644
--- a/drivers/net/ethernet/renesas/sh_eth.c
+++ b/drivers/net/ethernet/renesas/sh_eth.c
@@ -1481,6 +1481,7 @@ static int sh_eth_rx(struct net_device *ndev, u32 intr_status, int *quota)
if (mdp->cd->shift_rd0)
desc_status >>= 16;
+ 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++;
@@ -1496,12 +1497,11 @@ static int sh_eth_rx(struct net_device *ndev, u32 intr_status, int *quota)
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);