From: Pravin B Shelar pshelar@ovn.org
[ Upstream commit a17ad0961706244dce48ec941f7e476a38c0e727 ]
In some cases skb head could be locked and entire header data is pulled from skb. When skb_zerocopy() called in such cases, following BUG is triggered. This patch fixes it by copying entire skb in such cases. This could be optimized incase this is performance bottleneck.
---8<--- kernel BUG at net/core/skbuff.c:2961! invalid opcode: 0000 [#1] SMP PTI CPU: 2 PID: 0 Comm: swapper/2 Tainted: G OE 5.4.0-77-generic #86-Ubuntu Hardware name: OpenStack Foundation OpenStack Nova, BIOS 1.13.0-1ubuntu1.1 04/01/2014 RIP: 0010:skb_zerocopy+0x37a/0x3a0 RSP: 0018:ffffbcc70013ca38 EFLAGS: 00010246 Call Trace: <IRQ> queue_userspace_packet+0x2af/0x5e0 [openvswitch] ovs_dp_upcall+0x3d/0x60 [openvswitch] ovs_dp_process_packet+0x125/0x150 [openvswitch] ovs_vport_receive+0x77/0xd0 [openvswitch] netdev_port_receive+0x87/0x130 [openvswitch] netdev_frame_hook+0x4b/0x60 [openvswitch] __netif_receive_skb_core+0x2b4/0xc90 __netif_receive_skb_one_core+0x3f/0xa0 __netif_receive_skb+0x18/0x60 process_backlog+0xa9/0x160 net_rx_action+0x142/0x390 __do_softirq+0xe1/0x2d6 irq_exit+0xae/0xb0 do_IRQ+0x5a/0xf0 common_interrupt+0xf/0xf
Code that triggered BUG: int skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen) { int i, j = 0; int plen = 0; /* length of skb->head fragment */ int ret; struct page *page; unsigned int offset;
BUG_ON(!from->head_frag && !hlen);
Signed-off-by: Pravin B Shelar pshelar@ovn.org Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/core/skbuff.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 18dc8524e525..a278258e68cb 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -2702,8 +2702,11 @@ skb_zerocopy_headlen(const struct sk_buff *from)
if (!from->head_frag || skb_headlen(from) < L1_CACHE_BYTES || - skb_shinfo(from)->nr_frags >= MAX_SKB_FRAGS) + skb_shinfo(from)->nr_frags >= MAX_SKB_FRAGS) { hlen = skb_headlen(from); + if (!hlen) + hlen = from->len; + }
if (skb_has_frag_list(from)) hlen = from->len;