* [PATCH AUTOSEL 5.3 11/33] netfilter: conntrack: avoid possible false sharing
[not found] <20191025135505.24762-1-sashal@kernel.org>
@ 2019-10-25 13:54 ` Sasha Levin
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 16/33] netfilter: connlabels: prefer static lock initialiser Sasha Levin
1 sibling, 0 replies; 2+ messages in thread
From: Sasha Levin @ 2019-10-25 13:54 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Eric Dumazet, syzbot, Jozsef Kadlecsik, Florian Westphal,
Pablo Neira Ayuso, Jakub Kicinski, Sasha Levin, netfilter-devel,
coreteam, netdev
From: Eric Dumazet <edumazet@google.com>
[ Upstream commit e37542ba111f3974dc622ae0a21c1787318de500 ]
As hinted by KCSAN, we need at least one READ_ONCE()
to prevent a compiler optimization.
More details on :
https://github.com/google/ktsan/wiki/READ_ONCE-and-WRITE_ONCE#it-may-improve-performance
sysbot report :
BUG: KCSAN: data-race in __nf_ct_refresh_acct / __nf_ct_refresh_acct
read to 0xffff888123eb4f08 of 4 bytes by interrupt on cpu 0:
__nf_ct_refresh_acct+0xd4/0x1b0 net/netfilter/nf_conntrack_core.c:1796
nf_ct_refresh_acct include/net/netfilter/nf_conntrack.h:201 [inline]
nf_conntrack_tcp_packet+0xd40/0x3390 net/netfilter/nf_conntrack_proto_tcp.c:1161
nf_conntrack_handle_packet net/netfilter/nf_conntrack_core.c:1633 [inline]
nf_conntrack_in+0x410/0xaa0 net/netfilter/nf_conntrack_core.c:1727
ipv4_conntrack_in+0x27/0x40 net/netfilter/nf_conntrack_proto.c:178
nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline]
nf_hook_slow+0x83/0x160 net/netfilter/core.c:512
nf_hook include/linux/netfilter.h:260 [inline]
NF_HOOK include/linux/netfilter.h:303 [inline]
ip_rcv+0x12f/0x1a0 net/ipv4/ip_input.c:523
__netif_receive_skb_one_core+0xa7/0xe0 net/core/dev.c:5004
__netif_receive_skb+0x37/0xf0 net/core/dev.c:5118
netif_receive_skb_internal+0x59/0x190 net/core/dev.c:5208
napi_skb_finish net/core/dev.c:5671 [inline]
napi_gro_receive+0x28f/0x330 net/core/dev.c:5704
receive_buf+0x284/0x30b0 drivers/net/virtio_net.c:1061
virtnet_receive drivers/net/virtio_net.c:1323 [inline]
virtnet_poll+0x436/0x7d0 drivers/net/virtio_net.c:1428
napi_poll net/core/dev.c:6352 [inline]
net_rx_action+0x3ae/0xa50 net/core/dev.c:6418
__do_softirq+0x115/0x33f kernel/softirq.c:292
write to 0xffff888123eb4f08 of 4 bytes by task 7191 on cpu 1:
__nf_ct_refresh_acct+0xfb/0x1b0 net/netfilter/nf_conntrack_core.c:1797
nf_ct_refresh_acct include/net/netfilter/nf_conntrack.h:201 [inline]
nf_conntrack_tcp_packet+0xd40/0x3390 net/netfilter/nf_conntrack_proto_tcp.c:1161
nf_conntrack_handle_packet net/netfilter/nf_conntrack_core.c:1633 [inline]
nf_conntrack_in+0x410/0xaa0 net/netfilter/nf_conntrack_core.c:1727
ipv4_conntrack_local+0xbe/0x130 net/netfilter/nf_conntrack_proto.c:200
nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline]
nf_hook_slow+0x83/0x160 net/netfilter/core.c:512
nf_hook include/linux/netfilter.h:260 [inline]
__ip_local_out+0x1f7/0x2b0 net/ipv4/ip_output.c:114
ip_local_out+0x31/0x90 net/ipv4/ip_output.c:123
__ip_queue_xmit+0x3a8/0xa40 net/ipv4/ip_output.c:532
ip_queue_xmit+0x45/0x60 include/net/ip.h:236
__tcp_transmit_skb+0xdeb/0x1cd0 net/ipv4/tcp_output.c:1158
__tcp_send_ack+0x246/0x300 net/ipv4/tcp_output.c:3685
tcp_send_ack+0x34/0x40 net/ipv4/tcp_output.c:3691
tcp_cleanup_rbuf+0x130/0x360 net/ipv4/tcp.c:1575
Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7191 Comm: syz-fuzzer Not tainted 5.3.0+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Fixes: cc16921351d8 ("netfilter: conntrack: avoid same-timeout update")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: Jozsef Kadlecsik <kadlec@netfilter.org>
Cc: Florian Westphal <fw@strlen.de>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/netfilter/nf_conntrack_core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 81a8ef42b88d3..56b1cf82ed3aa 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -1793,8 +1793,8 @@ void __nf_ct_refresh_acct(struct nf_conn *ct,
if (nf_ct_is_confirmed(ct))
extra_jiffies += nfct_time_stamp;
- if (ct->timeout != extra_jiffies)
- ct->timeout = extra_jiffies;
+ if (READ_ONCE(ct->timeout) != extra_jiffies)
+ WRITE_ONCE(ct->timeout, extra_jiffies);
acct:
if (do_acct)
nf_ct_acct_update(ct, ctinfo, skb->len);
--
2.20.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* [PATCH AUTOSEL 5.3 16/33] netfilter: connlabels: prefer static lock initialiser
[not found] <20191025135505.24762-1-sashal@kernel.org>
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 11/33] netfilter: conntrack: avoid possible false sharing Sasha Levin
@ 2019-10-25 13:54 ` Sasha Levin
1 sibling, 0 replies; 2+ messages in thread
From: Sasha Levin @ 2019-10-25 13:54 UTC (permalink / raw)
To: linux-kernel, stable
Cc: Florian Westphal, Pablo Neira Ayuso, Sasha Levin,
netfilter-devel, coreteam, netdev
From: Florian Westphal <fw@strlen.de>
[ Upstream commit 105333435b4f3b21ffc325f32fae17719310db64 ]
seen during boot:
BUG: spinlock bad magic on CPU#2, swapper/0/1
lock: nf_connlabels_lock+0x0/0x60, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
Call Trace:
do_raw_spin_lock+0x14e/0x1b0
nf_connlabels_get+0x15/0x40
ct_init_net+0xc4/0x270
ops_init+0x56/0x1c0
register_pernet_operations+0x1c8/0x350
register_pernet_subsys+0x1f/0x40
tcf_register_action+0x7c/0x1a0
do_one_initcall+0x13d/0x2d9
Problem is that ct action init function can run before
connlabels_init(). Lock has not been initialised yet.
Fix it by using a static initialiser.
Fixes: b57dc7c13ea9 ("net/sched: Introduce action ct")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/netfilter/nf_conntrack_labels.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/net/netfilter/nf_conntrack_labels.c b/net/netfilter/nf_conntrack_labels.c
index 74b8113f7aebe..d1c6b2a2e7bd1 100644
--- a/net/netfilter/nf_conntrack_labels.c
+++ b/net/netfilter/nf_conntrack_labels.c
@@ -11,7 +11,7 @@
#include <net/netfilter/nf_conntrack_ecache.h>
#include <net/netfilter/nf_conntrack_labels.h>
-static spinlock_t nf_connlabels_lock;
+static __read_mostly DEFINE_SPINLOCK(nf_connlabels_lock);
static int replace_u32(u32 *address, u32 mask, u32 new)
{
@@ -89,7 +89,6 @@ int nf_conntrack_labels_init(void)
{
BUILD_BUG_ON(NF_CT_LABELS_MAX_SIZE / sizeof(long) >= U8_MAX);
- spin_lock_init(&nf_connlabels_lock);
return nf_ct_extend_register(&labels_extend);
}
--
2.20.1
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2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 11/33] netfilter: conntrack: avoid possible false sharing Sasha Levin
2019-10-25 13:54 ` [PATCH AUTOSEL 5.3 16/33] netfilter: connlabels: prefer static lock initialiser Sasha Levin
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