6.5-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit 9b271ebaf9a2c5c566a54bc6cd915962e8241130 ]
syzbot/KCSAN reported data-races in iptunnel_xmit_stats() [1]
This can run from multiple cpus without mutual exclusion.
Adopt SMP safe DEV_STATS_INC() to update dev->stats fields.
[1]
BUG: KCSAN: data-race in iptunnel_xmit / iptunnel_xmit
read-write to 0xffff8881353df170 of 8 bytes by task 30263 on cpu 1:
iptunnel_xmit_stats include/net/ip_tunnels.h:493 [inline]
iptunnel_xmit+0x432/0x4a0 net/ipv4/ip_tunnel_core.c:87
ip_tunnel_xmit+0x1477/0x1750 net/ipv4/ip_tunnel.c:831
__gre_xmit net/ipv4/ip_gre.c:469 [inline]
ipgre_xmit+0x516/0x570 net/ipv4/ip_gre.c:662
__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]
__bpf_tx_skb net/core/filter.c:2129 [inline]
__bpf_redirect_no_mac net/core/filter.c:2159 [inline]
__bpf_redirect+0x723/0x9c0 net/core/filter.c:2182
____bpf_clone_redirect net/core/filter.c:2453 [inline]
bpf_clone_redirect+0x16c/0x1d0 net/core/filter.c:2425
___bpf_prog_run+0xd7d/0x41e0 kernel/bpf/core.c:1954
__bpf_prog_run512+0x74/0xa0 kernel/bpf/core.c:2195
bpf_dispatcher_nop_func include/linux/bpf.h:1181 [inline]
__bpf_prog_run include/linux/filter.h:609 [inline]
bpf_prog_run include/linux/filter.h:616 [inline]
bpf_test_run+0x15d/0x3d0 net/bpf/test_run.c:423
bpf_prog_test_run_skb+0x77b/0xa00 net/bpf/test_run.c:1045
bpf_prog_test_run+0x265/0x3d0 kernel/bpf/syscall.c:3996
__sys_bpf+0x3af/0x780 kernel/bpf/syscall.c:5353
__do_sys_bpf kernel/bpf/syscall.c:5439 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5437 [inline]
__x64_sys_bpf+0x43/0x50 kernel/bpf/syscall.c:5437
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 0xffff8881353df170 of 8 bytes by task 30249 on cpu 0:
iptunnel_xmit_stats include/net/ip_tunnels.h:493 [inline]
iptunnel_xmit+0x432/0x4a0 net/ipv4/ip_tunnel_core.c:87
ip_tunnel_xmit+0x1477/0x1750 net/ipv4/ip_tunnel.c:831
__gre_xmit net/ipv4/ip_gre.c:469 [inline]
ipgre_xmit+0x516/0x570 net/ipv4/ip_gre.c:662
__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]
__bpf_tx_skb net/core/filter.c:2129 [inline]
__bpf_redirect_no_mac net/core/filter.c:2159 [inline]
__bpf_redirect+0x723/0x9c0 net/core/filter.c:2182
____bpf_clone_redirect net/core/filter.c:2453 [inline]
bpf_clone_redirect+0x16c/0x1d0 net/core/filter.c:2425
___bpf_prog_run+0xd7d/0x41e0 kernel/bpf/core.c:1954
__bpf_prog_run512+0x74/0xa0 kernel/bpf/core.c:2195
bpf_dispatcher_nop_func include/linux/bpf.h:1181 [inline]
__bpf_prog_run include/linux/filter.h:609 [inline]
bpf_prog_run include/linux/filter.h:616 [inline]
bpf_test_run+0x15d/0x3d0 net/bpf/test_run.c:423
bpf_prog_test_run_skb+0x77b/0xa00 net/bpf/test_run.c:1045
bpf_prog_test_run+0x265/0x3d0 kernel/bpf/syscall.c:3996
__sys_bpf+0x3af/0x780 kernel/bpf/syscall.c:5353
__do_sys_bpf kernel/bpf/syscall.c:5439 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5437 [inline]
__x64_sys_bpf+0x43/0x50 kernel/bpf/syscall.c:5437
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: 0x0000000000018830 -> 0x0000000000018831
Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 30249 Comm: syz-executor.4 Not tainted 6.5.0-syzkaller-11704-g3f86ed6ec0b3 #0
Fixes: 039f50629b7f ("ip_tunnel: Move stats update to iptunnel_xmit()")
Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx>
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
include/net/ip_tunnels.h | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h
index ed4b6ad3fcac8..cd0e2744f66f3 100644
--- a/include/net/ip_tunnels.h
+++ b/include/net/ip_tunnels.h
@@ -482,15 +482,14 @@ static inline void iptunnel_xmit_stats(struct net_device *dev, int pkt_len)
u64_stats_inc(&tstats->tx_packets);
u64_stats_update_end(&tstats->syncp);
put_cpu_ptr(tstats);
+ return;
+ }
+
+ if (pkt_len < 0) {
+ DEV_STATS_INC(dev, tx_errors);
+ DEV_STATS_INC(dev, tx_aborted_errors);
} else {
- struct net_device_stats *err_stats = &dev->stats;
-
- if (pkt_len < 0) {
- err_stats->tx_errors++;
- err_stats->tx_aborted_errors++;
- } else {
- err_stats->tx_dropped++;
- }
+ DEV_STATS_INC(dev, tx_dropped);
}
}
--
2.40.1
