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author | Eric Dumazet <edumazet@google.com> | 2019-11-08 05:29:11 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-01-12 13:22:45 +0300 |
commit | 009d455f968efcc7b0fde1263e0c8158cc3d0385 (patch) | |
tree | fc562fc7c843f2b96ca514b3b6c2034300cf1cf9 /net | |
parent | dcaf09979185779ca9880a6ed22061ebddc8b6d2 (diff) | |
download | linux-009d455f968efcc7b0fde1263e0c8158cc3d0385.tar.xz |
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')
-rw-r--r-- | net/core/neighbour.c | 4 | ||||
-rw-r--r-- | net/ethernet/eth.c | 7 |
2 files changed, 8 insertions, 3 deletions
diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 8aef689b8f32..af1ecd0e7b07 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); @@ -1323,7 +1323,7 @@ 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 { diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c index 52dcd414c2af..3f51b4e590b1 100644 --- a/net/ethernet/eth.c +++ b/net/ethernet/eth.c @@ -235,7 +235,12 @@ int eth_header_cache(const struct neighbour *neigh, struct hh_cache *hh, __be16 eth->h_proto = type; memcpy(eth->h_source, dev->dev_addr, ETH_ALEN); memcpy(eth->h_dest, neigh->ha, ETH_ALEN); - hh->hh_len = ETH_HLEN; + + /* Pairs with READ_ONCE() in neigh_resolve_output(), + * neigh_hh_output() and neigh_update_hhs(). + */ + smp_store_release(&hh->hh_len, ETH_HLEN); + return 0; } EXPORT_SYMBOL(eth_header_cache); |