net: bridge: use DEV_STATS_INC()

syzbot/KCSAN reported data-races in br_handle_frame_finish() [1]
This function can run from multiple cpus without mutual exclusion.

Adopt SMP safe DEV_STATS_INC() to update dev->stats fields.

Handles updates to dev->stats.tx_dropped while we are at it.

[1]
BUG: KCSAN: data-race in br_handle_frame_finish / br_handle_frame_finish

read-write to 0xffff8881374b2178 of 8 bytes by interrupt on cpu 1:
br_handle_frame_finish+0xd4f/0xef0 net/bridge/br_input.c:189
br_nf_hook_thresh+0x1ed/0x220
br_nf_pre_routing_finish_ipv6+0x50f/0x540
NF_HOOK include/linux/netfilter.h:304 [inline]
br_nf_pre_routing_ipv6+0x1e3/0x2a0 net/bridge/br_netfilter_ipv6.c:178
br_nf_pre_routing+0x526/0xba0 net/bridge/br_netfilter_hooks.c:508
nf_hook_entry_hookfn include/linux/netfilter.h:144 [inline]
nf_hook_bridge_pre net/bridge/br_input.c:272 [inline]
br_handle_frame+0x4c9/0x940 net/bridge/br_input.c:417
__netif_receive_skb_core+0xa8a/0x21e0 net/core/dev.c:5417
__netif_receive_skb_one_core net/core/dev.c:5521 [inline]
__netif_receive_skb+0x57/0x1b0 net/core/dev.c:5637
process_backlog+0x21f/0x380 net/core/dev.c:5965
__napi_poll+0x60/0x3b0 net/core/dev.c:6527
napi_poll net/core/dev.c:6594 [inline]
net_rx_action+0x32b/0x750 net/core/dev.c:6727
__do_softirq+0xc1/0x265 kernel/softirq.c:553
run_ksoftirqd+0x17/0x20 kernel/softirq.c:921
smpboot_thread_fn+0x30a/0x4a0 kernel/smpboot.c:164
kthread+0x1d7/0x210 kernel/kthread.c:388
ret_from_fork+0x48/0x60 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304

read-write to 0xffff8881374b2178 of 8 bytes by interrupt on cpu 0:
br_handle_frame_finish+0xd4f/0xef0 net/bridge/br_input.c:189
br_nf_hook_thresh+0x1ed/0x220
br_nf_pre_routing_finish_ipv6+0x50f/0x540
NF_HOOK include/linux/netfilter.h:304 [inline]
br_nf_pre_routing_ipv6+0x1e3/0x2a0 net/bridge/br_netfilter_ipv6.c:178
br_nf_pre_routing+0x526/0xba0 net/bridge/br_netfilter_hooks.c:508
nf_hook_entry_hookfn include/linux/netfilter.h:144 [inline]
nf_hook_bridge_pre net/bridge/br_input.c:272 [inline]
br_handle_frame+0x4c9/0x940 net/bridge/br_input.c:417
__netif_receive_skb_core+0xa8a/0x21e0 net/core/dev.c:5417
__netif_receive_skb_one_core net/core/dev.c:5521 [inline]
__netif_receive_skb+0x57/0x1b0 net/core/dev.c:5637
process_backlog+0x21f/0x380 net/core/dev.c:5965
__napi_poll+0x60/0x3b0 net/core/dev.c:6527
napi_poll net/core/dev.c:6594 [inline]
net_rx_action+0x32b/0x750 net/core/dev.c:6727
__do_softirq+0xc1/0x265 kernel/softirq.c:553
do_softirq+0x5e/0x90 kernel/softirq.c:454
__local_bh_enable_ip+0x64/0x70 kernel/softirq.c:381
__raw_spin_unlock_bh include/linux/spinlock_api_smp.h:167 [inline]
_raw_spin_unlock_bh+0x36/0x40 kernel/locking/spinlock.c:210
spin_unlock_bh include/linux/spinlock.h:396 [inline]
batadv_tt_local_purge+0x1a8/0x1f0 net/batman-adv/translation-table.c:1356
batadv_tt_purge+0x2b/0x630 net/batman-adv/translation-table.c:3560
process_one_work kernel/workqueue.c:2630 [inline]
process_scheduled_works+0x5b8/0xa30 kernel/workqueue.c:2703
worker_thread+0x525/0x730 kernel/workqueue.c:2784
kthread+0x1d7/0x210 kernel/kthread.c:388
ret_from_fork+0x48/0x60 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:304

value changed: 0x00000000000d7190 -> 0x00000000000d7191

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 14848 Comm: kworker/u4:11 Not tainted 6.6.0-rc1-syzkaller-00236-gad8a69f361b9 #0

Fixes: 1c29fc4989bc ("[BRIDGE]: keep track of received multicast packets")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Roopa Prabhu <roopa@nvidia.com>
Cc: Nikolay Aleksandrov <razor@blackwall.org>
Cc: bridge@lists.linux-foundation.org
Acked-by: Nikolay Aleksandrov <razor@blackwall.org>
Link: https://lore.kernel.org/r/20230918091351.1356153-1-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c
index 9d7bc8b96b53a911d5add8d0b21736358441755f..7431f89e897b9549a0c35d9431e36b6de2e80022 100644 (file)
--- a/net/bridge/br_forward.c
+++ b/net/bridge/br_forward.c
@@ -124,7 +124,7 @@ static int deliver_clone(const struct net_bridge_port *prev,
 
        skb = skb_clone(skb, GFP_ATOMIC);
        if (!skb) {
-               dev->stats.tx_dropped++;
+               DEV_STATS_INC(dev, tx_dropped);
                return -ENOMEM;
        }
 
@@ -268,7 +268,7 @@ static void maybe_deliver_addr(struct net_bridge_port *p, struct sk_buff *skb,
 
        skb = skb_copy(skb, GFP_ATOMIC);
        if (!skb) {
-               dev->stats.tx_dropped++;
+               DEV_STATS_INC(dev, tx_dropped);
                return;
        }
 

diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c
index c34a0b0901b07de9e2a3f172527a2bf1c0b6f0b7..c729528b5e85f3a28eff6bd346c18bc11288e7a8 100644 (file)
--- a/net/bridge/br_input.c
+++ b/net/bridge/br_input.c
@@ -181,12 +181,12 @@ int br_handle_frame_finish(struct net *net, struct sock *sk, struct sk_buff *skb
                        if ((mdst && mdst->host_joined) ||
                            br_multicast_is_router(brmctx, skb)) {
                                local_rcv = true;
-                               br->dev->stats.multicast++;
+                               DEV_STATS_INC(br->dev, multicast);
                        }
                        mcast_hit = true;
                } else {
                        local_rcv = true;
-                       br->dev->stats.multicast++;
+                       DEV_STATS_INC(br->dev, multicast);
                }
                break;
        case BR_PKT_UNICAST: