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| author | Eric Dumazet <edumazet@google.com> | 2019-11-07 20:08:19 -0800 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-11-08 13:59:53 -0800 |
| commit | 1b53d64435d56902fc234ff2507142d971a09687 (patch) | |
| tree | 4c83698df30beff818d18a9f16eb343363dd65b7 | |
| parent | ad8a7220355d39cddce8eac1cea9677333e8b821 (diff) | |
| download | linux-1b53d64435d56902fc234ff2507142d971a09687.tar.bz2 | |
net: fix data-race in neigh_event_send()
KCSAN reported the following data-race [1]
The fix will also prevent the compiler from optimizing out
the condition.
[1]
BUG: KCSAN: data-race in neigh_resolve_output / neigh_resolve_output
write to 0xffff8880a41dba78 of 8 bytes by interrupt on cpu 1:
neigh_event_send include/net/neighbour.h:443 [inline]
neigh_resolve_output+0x78/0x480 net/core/neighbour.c:1474
neigh_output include/net/neighbour.h:511 [inline]
ip_finish_output2+0x4af/0xe40 net/ipv4/ip_output.c:228
__ip_finish_output net/ipv4/ip_output.c:308 [inline]
__ip_finish_output+0x23a/0x490 net/ipv4/ip_output.c:290
ip_finish_output+0x41/0x160 net/ipv4/ip_output.c:318
NF_HOOK_COND include/linux/netfilter.h:294 [inline]
ip_output+0xdf/0x210 net/ipv4/ip_output.c:432
dst_output include/net/dst.h:436 [inline]
ip_local_out+0x74/0x90 net/ipv4/ip_output.c:125
__ip_queue_xmit+0x3a8/0xa40 net/ipv4/ip_output.c:532
ip_queue_xmit+0x45/0x60 include/net/ip.h:237
__tcp_transmit_skb+0xe81/0x1d60 net/ipv4/tcp_output.c:1169
tcp_transmit_skb net/ipv4/tcp_output.c:1185 [inline]
__tcp_retransmit_skb+0x4bd/0x15f0 net/ipv4/tcp_output.c:2976
tcp_retransmit_skb+0x36/0x1a0 net/ipv4/tcp_output.c:2999
tcp_retransmit_timer+0x719/0x16d0 net/ipv4/tcp_timer.c:515
tcp_write_timer_handler+0x42d/0x510 net/ipv4/tcp_timer.c:598
tcp_write_timer+0xd1/0xf0 net/ipv4/tcp_timer.c:618
read to 0xffff8880a41dba78 of 8 bytes by interrupt on cpu 0:
neigh_event_send include/net/neighbour.h:442 [inline]
neigh_resolve_output+0x57/0x480 net/core/neighbour.c:1474
neigh_output include/net/neighbour.h:511 [inline]
ip_finish_output2+0x4af/0xe40 net/ipv4/ip_output.c:228
__ip_finish_output net/ipv4/ip_output.c:308 [inline]
__ip_finish_output+0x23a/0x490 net/ipv4/ip_output.c:290
ip_finish_output+0x41/0x160 net/ipv4/ip_output.c:318
NF_HOOK_COND include/linux/netfilter.h:294 [inline]
ip_output+0xdf/0x210 net/ipv4/ip_output.c:432
dst_output include/net/dst.h:436 [inline]
ip_local_out+0x74/0x90 net/ipv4/ip_output.c:125
__ip_queue_xmit+0x3a8/0xa40 net/ipv4/ip_output.c:532
ip_queue_xmit+0x45/0x60 include/net/ip.h:237
__tcp_transmit_skb+0xe81/0x1d60 net/ipv4/tcp_output.c:1169
tcp_transmit_skb net/ipv4/tcp_output.c:1185 [inline]
__tcp_retransmit_skb+0x4bd/0x15f0 net/ipv4/tcp_output.c:2976
tcp_retransmit_skb+0x36/0x1a0 net/ipv4/tcp_output.c:2999
tcp_retransmit_timer+0x719/0x16d0 net/ipv4/tcp_timer.c:515
tcp_write_timer_handler+0x42d/0x510 net/ipv4/tcp_timer.c:598
Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.4.0-rc3+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/net/neighbour.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/include/net/neighbour.h b/include/net/neighbour.h index 50a67bd6a434..b8452cc0e059 100644 --- a/include/net/neighbour.h +++ b/include/net/neighbour.h @@ -439,8 +439,8 @@ static inline int neigh_event_send(struct neighbour *neigh, struct sk_buff *skb) { unsigned long now = jiffies; - if (neigh->used != now) - neigh->used = now; + if (READ_ONCE(neigh->used) != now) + WRITE_ONCE(neigh->used, now); if (!(neigh->nud_state&(NUD_CONNECTED|NUD_DELAY|NUD_PROBE))) return __neigh_event_send(neigh, skb); return 0; |