From: Sergei Shtylyov <sergei.shtylyov@cogentembedded•com>
To: netdev@vger•kernel.org, yashi@atmark-techno•com
Cc: linux-sh@vger•kernel.org
Subject: [PATCH v3] sh_eth: fix kernel oops in skb_put()
Date: Fri, 04 Dec 2015 01:45:40 +0300 [thread overview]
Message-ID: <1498048.4g9dLWgJuk@wasted.cogentembedded.com> (raw)
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>
---
The patch is against Dave Miller's 'net.git' repo.
Changes in version 3:
- refreshed the patch;
- reformatted the changelog;
- removed [RFT] from the subject.
Changes in version 2:
- moved reading 'mdp->rx_skbuff[entry]' earlier to avoid *goto*.
drivers/net/ethernet/renesas/sh_eth.c | 4 ++--
drivers/net/ethernet/renesas/sh_eth.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
Index: net/drivers/net/ethernet/renesas/sh_eth.c
===================================================================
--- net.orig/drivers/net/ethernet/renesas/sh_eth.c
+++ net/drivers/net/ethernet/renesas/sh_eth.c
@@ -1462,6 +1462,7 @@ 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++;
@@ -1477,12 +1478,11 @@ 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);
next reply other threads:[~2015-12-03 22:45 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-03 22:45 Sergei Shtylyov [this message]
2015-12-05 22:46 ` [PATCH v3] sh_eth: fix kernel oops in skb_put() David Miller
2015-12-12 15:17 ` Sergei Shtylyov
2015-12-14 21:24 ` David Miller
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