diff options
| author | Eric Dumazet <edumazet@google.com> | 2019-11-07 18:29:11 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-01-12 11:24:19 +0100 |
| commit | 36d6d826d57173ec5e29df85942ca7055d555020 (patch) | |
| tree | b38f69bc02e04758b3ce4f89f2b20335d26d2634 /net/core | |
| parent | 214910fc069f32149428d1bafebcd6ecd456c10e (diff) | |
net: add annotations on hh->hh_len lockless accesses
[ Upstream commit c305c6ae79e2ce20c22660ceda94f0d86d639a82 ]
KCSAN reported a data-race [1]
While we can use READ_ONCE() on the read sides,
we need to make sure hh->hh_len is written last.
[1]
BUG: KCSAN: data-race in eth_header_cache / neigh_resolve_output
write to 0xffff8880b9dedcb8 of 4 bytes by task 29760 on cpu 0:
eth_header_cache+0xa9/0xd0 net/ethernet/eth.c:247
neigh_hh_init net/core/neighbour.c:1463 [inline]
neigh_resolve_output net/core/neighbour.c:1480 [inline]
neigh_resolve_output+0x415/0x470 net/core/neighbour.c:1470
neigh_output include/net/neighbour.h:511 [inline]
ip6_finish_output2+0x7a2/0xec0 net/ipv6/ip6_output.c:116
__ip6_finish_output net/ipv6/ip6_output.c:142 [inline]
__ip6_finish_output+0x2d7/0x330 net/ipv6/ip6_output.c:127
ip6_finish_output+0x41/0x160 net/ipv6/ip6_output.c:152
NF_HOOK_COND include/linux/netfilter.h:294 [inline]
ip6_output+0xf2/0x280 net/ipv6/ip6_output.c:175
dst_output include/net/dst.h:436 [inline]
NF_HOOK include/linux/netfilter.h:305 [inline]
ndisc_send_skb+0x459/0x5f0 net/ipv6/ndisc.c:505
ndisc_send_ns+0x207/0x430 net/ipv6/ndisc.c:647
rt6_probe_deferred+0x98/0xf0 net/ipv6/route.c:615
process_one_work+0x3d4/0x890 kernel/workqueue.c:2269
worker_thread+0xa0/0x800 kernel/workqueue.c:2415
kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352
read to 0xffff8880b9dedcb8 of 4 bytes by task 29572 on cpu 1:
neigh_resolve_output net/core/neighbour.c:1479 [inline]
neigh_resolve_output+0x113/0x470 net/core/neighbour.c:1470
neigh_output include/net/neighbour.h:511 [inline]
ip6_finish_output2+0x7a2/0xec0 net/ipv6/ip6_output.c:116
__ip6_finish_output net/ipv6/ip6_output.c:142 [inline]
__ip6_finish_output+0x2d7/0x330 net/ipv6/ip6_output.c:127
ip6_finish_output+0x41/0x160 net/ipv6/ip6_output.c:152
NF_HOOK_COND include/linux/netfilter.h:294 [inline]
ip6_output+0xf2/0x280 net/ipv6/ip6_output.c:175
dst_output include/net/dst.h:436 [inline]
NF_HOOK include/linux/netfilter.h:305 [inline]
ndisc_send_skb+0x459/0x5f0 net/ipv6/ndisc.c:505
ndisc_send_ns+0x207/0x430 net/ipv6/ndisc.c:647
rt6_probe_deferred+0x98/0xf0 net/ipv6/route.c:615
process_one_work+0x3d4/0x890 kernel/workqueue.c:2269
worker_thread+0xa0/0x800 kernel/workqueue.c:2415
kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352
Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 29572 Comm: kworker/1:4 Not tainted 5.4.0-rc6+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events rt6_probe_deferred
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/neighbour.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 44a29be7bfff..cd85cee14bd0 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -1058,7 +1058,7 @@ static void neigh_update_hhs(struct neighbour *neigh) if (update) { hh = &neigh->hh; - if (hh->hh_len) { + if (READ_ONCE(hh->hh_len)) { write_seqlock_bh(&hh->hh_lock); update(hh, neigh->dev, neigh->ha); write_sequnlock_bh(&hh->hh_lock); @@ -1319,7 +1319,7 @@ int neigh_resolve_output(struct neighbour *neigh, struct sk_buff *skb) struct net_device *dev = neigh->dev; unsigned int seq; - if (dev->header_ops->cache && !neigh->hh.hh_len) + if (dev->header_ops->cache && !READ_ONCE(neigh->hh.hh_len)) neigh_hh_init(neigh); do { |