This is a note to let you know that I've just added the patch titled sh_eth: fix kernel oops in skb_put() to the 4.1-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: sh_eth-fix-kernel-oops-in-skb_put.patch and it can be found in the queue-4.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Wed Dec 30 19:52:45 PST 2015 From: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx> Date: Fri, 4 Dec 2015 01:45:40 +0300 Subject: sh_eth: fix kernel oops in skb_put() From: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx> [ 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@xxxxxxxxxxxxxxxxx> Signed-off-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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 @@ -1481,6 +1481,7 @@ static int sh_eth_rx(struct net_device * 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->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); Patches currently in stable-queue which might be from sergei.shtylyov@xxxxxxxxxxxxxxxxxx are queue-4.1/sh_eth-fix-kernel-oops-in-skb_put.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html