5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet edumazet@google.com
commit f7c4e3e5d4f6609b4725a97451948ca2e425379a upstream.
syzbot/KCSAN reported data-races in xfrm whenever dev->stats fields are updated.
It appears all of these updates can happen from multiple cpus.
Adopt SMP safe DEV_STATS_INC() to update dev->stats fields.
BUG: KCSAN: data-race in xfrmi_xmit / xfrmi_xmit
read-write to 0xffff88813726b160 of 8 bytes by task 23986 on cpu 1: xfrmi_xmit+0x74e/0xb20 net/xfrm/xfrm_interface_core.c:583 __netdev_start_xmit include/linux/netdevice.h:4889 [inline] netdev_start_xmit include/linux/netdevice.h:4903 [inline] xmit_one net/core/dev.c:3544 [inline] dev_hard_start_xmit+0x11b/0x3f0 net/core/dev.c:3560 __dev_queue_xmit+0xeee/0x1de0 net/core/dev.c:4340 dev_queue_xmit include/linux/netdevice.h:3082 [inline] neigh_connected_output+0x231/0x2a0 net/core/neighbour.c:1581 neigh_output include/net/neighbour.h:542 [inline] ip_finish_output2+0x74a/0x850 net/ipv4/ip_output.c:230 ip_finish_output+0xf4/0x240 net/ipv4/ip_output.c:318 NF_HOOK_COND include/linux/netfilter.h:293 [inline] ip_output+0xe5/0x1b0 net/ipv4/ip_output.c:432 dst_output include/net/dst.h:458 [inline] ip_local_out net/ipv4/ip_output.c:127 [inline] ip_send_skb+0x72/0xe0 net/ipv4/ip_output.c:1487 udp_send_skb+0x6a4/0x990 net/ipv4/udp.c:963 udp_sendmsg+0x1249/0x12d0 net/ipv4/udp.c:1246 inet_sendmsg+0x63/0x80 net/ipv4/af_inet.c:840 sock_sendmsg_nosec net/socket.c:730 [inline] sock_sendmsg net/socket.c:753 [inline] ____sys_sendmsg+0x37c/0x4d0 net/socket.c:2540 ___sys_sendmsg net/socket.c:2594 [inline] __sys_sendmmsg+0x269/0x500 net/socket.c:2680 __do_sys_sendmmsg net/socket.c:2709 [inline] __se_sys_sendmmsg net/socket.c:2706 [inline] __x64_sys_sendmmsg+0x57/0x60 net/socket.c:2706 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd
read-write to 0xffff88813726b160 of 8 bytes by task 23987 on cpu 0: xfrmi_xmit+0x74e/0xb20 net/xfrm/xfrm_interface_core.c:583 __netdev_start_xmit include/linux/netdevice.h:4889 [inline] netdev_start_xmit include/linux/netdevice.h:4903 [inline] xmit_one net/core/dev.c:3544 [inline] dev_hard_start_xmit+0x11b/0x3f0 net/core/dev.c:3560 __dev_queue_xmit+0xeee/0x1de0 net/core/dev.c:4340 dev_queue_xmit include/linux/netdevice.h:3082 [inline] neigh_connected_output+0x231/0x2a0 net/core/neighbour.c:1581 neigh_output include/net/neighbour.h:542 [inline] ip_finish_output2+0x74a/0x850 net/ipv4/ip_output.c:230 ip_finish_output+0xf4/0x240 net/ipv4/ip_output.c:318 NF_HOOK_COND include/linux/netfilter.h:293 [inline] ip_output+0xe5/0x1b0 net/ipv4/ip_output.c:432 dst_output include/net/dst.h:458 [inline] ip_local_out net/ipv4/ip_output.c:127 [inline] ip_send_skb+0x72/0xe0 net/ipv4/ip_output.c:1487 udp_send_skb+0x6a4/0x990 net/ipv4/udp.c:963 udp_sendmsg+0x1249/0x12d0 net/ipv4/udp.c:1246 inet_sendmsg+0x63/0x80 net/ipv4/af_inet.c:840 sock_sendmsg_nosec net/socket.c:730 [inline] sock_sendmsg net/socket.c:753 [inline] ____sys_sendmsg+0x37c/0x4d0 net/socket.c:2540 ___sys_sendmsg net/socket.c:2594 [inline] __sys_sendmmsg+0x269/0x500 net/socket.c:2680 __do_sys_sendmmsg net/socket.c:2709 [inline] __se_sys_sendmmsg net/socket.c:2706 [inline] __x64_sys_sendmmsg+0x57/0x60 net/socket.c:2706 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd
value changed: 0x00000000000010d7 -> 0x00000000000010d8
Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 23987 Comm: syz-executor.5 Not tainted 6.5.0-syzkaller-10885-g0468be89b3fa #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Fixes: f203b76d7809 ("xfrm: Add virtual xfrm interfaces") Reported-by: syzbot syzkaller@googlegroups.com Signed-off-by: Eric Dumazet edumazet@google.com Cc: Steffen Klassert steffen.klassert@secunet.com Signed-off-by: Steffen Klassert steffen.klassert@secunet.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/xfrm/xfrm_interface_core.c | 22 ++++++++++------------ 1 file changed, 10 insertions(+), 12 deletions(-)
--- a/net/xfrm/xfrm_interface_core.c +++ b/net/xfrm/xfrm_interface_core.c @@ -219,8 +219,8 @@ static int xfrmi_rcv_cb(struct sk_buff * skb->dev = dev;
if (err) { - dev->stats.rx_errors++; - dev->stats.rx_dropped++; + DEV_STATS_INC(dev, rx_errors); + DEV_STATS_INC(dev, rx_dropped);
return 0; } @@ -260,7 +260,6 @@ static int xfrmi_xmit2(struct sk_buff *skb, struct net_device *dev, struct flowi *fl) { struct xfrm_if *xi = netdev_priv(dev); - struct net_device_stats *stats = &xi->dev->stats; struct dst_entry *dst = skb_dst(skb); unsigned int length = skb->len; struct net_device *tdev; @@ -286,7 +285,7 @@ xfrmi_xmit2(struct sk_buff *skb, struct tdev = dst->dev;
if (tdev == dev) { - stats->collisions++; + DEV_STATS_INC(dev, collisions); net_warn_ratelimited("%s: Local routing loop detected!\n", dev->name); goto tx_err_dst_release; @@ -329,13 +328,13 @@ xmit: tstats->tx_packets++; u64_stats_update_end(&tstats->syncp); } else { - stats->tx_errors++; - stats->tx_aborted_errors++; + DEV_STATS_INC(dev, tx_errors); + DEV_STATS_INC(dev, tx_aborted_errors); }
return 0; tx_err_link_failure: - stats->tx_carrier_errors++; + DEV_STATS_INC(dev, tx_carrier_errors); dst_link_failure(skb); tx_err_dst_release: dst_release(dst); @@ -345,7 +344,6 @@ tx_err_dst_release: static netdev_tx_t xfrmi_xmit(struct sk_buff *skb, struct net_device *dev) { struct xfrm_if *xi = netdev_priv(dev); - struct net_device_stats *stats = &xi->dev->stats; struct dst_entry *dst = skb_dst(skb); struct flowi fl; int ret; @@ -362,7 +360,7 @@ static netdev_tx_t xfrmi_xmit(struct sk_ dst = ip6_route_output(dev_net(dev), NULL, &fl.u.ip6); if (dst->error) { dst_release(dst); - stats->tx_carrier_errors++; + DEV_STATS_INC(dev, tx_carrier_errors); goto tx_err; } skb_dst_set(skb, dst); @@ -378,7 +376,7 @@ static netdev_tx_t xfrmi_xmit(struct sk_ fl.u.ip4.flowi4_flags |= FLOWI_FLAG_ANYSRC; rt = __ip_route_output_key(dev_net(dev), &fl.u.ip4); if (IS_ERR(rt)) { - stats->tx_carrier_errors++; + DEV_STATS_INC(dev, tx_carrier_errors); goto tx_err; } skb_dst_set(skb, &rt->dst); @@ -397,8 +395,8 @@ static netdev_tx_t xfrmi_xmit(struct sk_ return NETDEV_TX_OK;
tx_err: - stats->tx_errors++; - stats->tx_dropped++; + DEV_STATS_INC(dev, tx_errors); + DEV_STATS_INC(dev, tx_dropped); kfree_skb(skb); return NETDEV_TX_OK; }