path: root/net
diff options
authorEric Dumazet <edumazet@google.com>2019-10-09 15:21:13 -0700
committerJakub Kicinski <jakub.kicinski@netronome.com>2019-10-09 21:42:59 -0700
commit8265792bf8871acc2d00fd03883d830e2249d395 (patch)
tree02bb19666f478380c450e3cb12b04e180c5118fd /net
parenttcp: annotate lockless access to tcp_memory_pressure (diff)
net: silence KCSAN warnings around sk_add_backlog() calls
sk_add_backlog() callers usually read sk->sk_rcvbuf without owning the socket lock. This means sk_rcvbuf value can be changed by other cpus, and KCSAN complains. Add READ_ONCE() annotations to document the lockless nature of these reads. Note that writes over sk_rcvbuf should also use WRITE_ONCE(), but this will be done in separate patches to ease stable backports (if we decide this is relevant for stable trees). BUG: KCSAN: data-race in tcp_add_backlog / tcp_recvmsg write to 0xffff88812ab369f8 of 8 bytes by interrupt on cpu 1: __sk_add_backlog include/net/sock.h:902 [inline] sk_add_backlog include/net/sock.h:933 [inline] tcp_add_backlog+0x45a/0xcc0 net/ipv4/tcp_ipv4.c:1737 tcp_v4_rcv+0x1aba/0x1bf0 net/ipv4/tcp_ipv4.c:1925 ip_protocol_deliver_rcu+0x51/0x470 net/ipv4/ip_input.c:204 ip_local_deliver_finish+0x110/0x140 net/ipv4/ip_input.c:231 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ip_local_deliver+0x133/0x210 net/ipv4/ip_input.c:252 dst_input include/net/dst.h:442 [inline] ip_rcv_finish+0x121/0x160 net/ipv4/ip_input.c:413 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ip_rcv+0x18f/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 read to 0xffff88812ab369f8 of 8 bytes by task 7271 on cpu 0: tcp_recvmsg+0x470/0x1a30 net/ipv4/tcp.c:2047 inet_recvmsg+0xbb/0x250 net/ipv4/af_inet.c:838 sock_recvmsg_nosec net/socket.c:871 [inline] sock_recvmsg net/socket.c:889 [inline] sock_recvmsg+0x92/0xb0 net/socket.c:885 sock_read_iter+0x15f/0x1e0 net/socket.c:967 call_read_iter include/linux/fs.h:1864 [inline] new_sync_read+0x389/0x4f0 fs/read_write.c:414 __vfs_read+0xb1/0xc0 fs/read_write.c:427 vfs_read fs/read_write.c:461 [inline] vfs_read+0x143/0x2c0 fs/read_write.c:446 ksys_read+0xd5/0x1b0 fs/read_write.c:587 __do_sys_read fs/read_write.c:597 [inline] __se_sys_read fs/read_write.c:595 [inline] __x64_sys_read+0x4c/0x60 fs/read_write.c:595 do_syscall_64+0xcf/0x2f0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 7271 Comm: syz-fuzzer Not tainted 5.3.0+ #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: Jakub Kicinski <jakub.kicinski@netronome.com>
Diffstat (limited to 'net')
6 files changed, 10 insertions, 10 deletions
diff --git a/net/core/sock.c b/net/core/sock.c
index 50647a10fdb7..1cf06934da50 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -522,7 +522,7 @@ int __sk_receive_skb(struct sock *sk, struct sk_buff *skb,
rc = sk_backlog_rcv(sk, skb);
mutex_release(&sk->sk_lock.dep_map, 1, _RET_IP_);
- } else if (sk_add_backlog(sk, skb, sk->sk_rcvbuf)) {
+ } else if (sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf))) {
goto discard_and_relse;
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index bf124b1742df..492bf6a6b023 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1644,7 +1644,7 @@ int tcp_v4_early_demux(struct sk_buff *skb)
bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb)
- u32 limit = sk->sk_rcvbuf + sk->sk_sndbuf;
+ u32 limit = READ_ONCE(sk->sk_rcvbuf) + READ_ONCE(sk->sk_sndbuf);
struct skb_shared_info *shinfo;
const struct tcphdr *th;
struct tcphdr *thtail;
diff --git a/net/llc/llc_conn.c b/net/llc/llc_conn.c
index a79b739eb223..7b620acaca9e 100644
--- a/net/llc/llc_conn.c
+++ b/net/llc/llc_conn.c
@@ -813,7 +813,7 @@ void llc_conn_handler(struct llc_sap *sap, struct sk_buff *skb)
else {
dprintk("%s: adding to backlog...\n", __func__);
llc_set_backlog_type(skb, LLC_PACKET);
- if (sk_add_backlog(sk, skb, sk->sk_rcvbuf))
+ if (sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf)))
goto drop_unlock;
diff --git a/net/sctp/input.c b/net/sctp/input.c
index f2771375bfc0..2277981559d0 100644
--- a/net/sctp/input.c
+++ b/net/sctp/input.c
@@ -322,7 +322,7 @@ int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
if (sock_owned_by_user(sk) || !sctp_newsk_ready(sk)) {
- if (sk_add_backlog(sk, skb, sk->sk_rcvbuf))
+ if (sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf)))
backloged = 1;
@@ -337,7 +337,7 @@ int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
return 0;
} else {
if (!sctp_newsk_ready(sk)) {
- if (!sk_add_backlog(sk, skb, sk->sk_rcvbuf))
+ if (!sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf)))
return 0;
} else {
@@ -364,7 +364,7 @@ static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb)
struct sctp_ep_common *rcvr = chunk->rcvr;
int ret;
- ret = sk_add_backlog(sk, skb, sk->sk_rcvbuf);
+ ret = sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf));
if (!ret) {
/* Hold the assoc/ep while hanging on the backlog queue.
* This way, we know structures we need will not disappear
diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 3b9f8cc328f5..7c736cfec57f 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -2119,13 +2119,13 @@ static unsigned int rcvbuf_limit(struct sock *sk, struct sk_buff *skb)
struct tipc_msg *hdr = buf_msg(skb);
if (unlikely(msg_in_group(hdr)))
- return sk->sk_rcvbuf;
+ return READ_ONCE(sk->sk_rcvbuf);
if (unlikely(!msg_connected(hdr)))
- return sk->sk_rcvbuf << msg_importance(hdr);
+ return READ_ONCE(sk->sk_rcvbuf) << msg_importance(hdr);
if (likely(tsk->peer_caps & TIPC_BLOCK_FLOWCTL))
- return sk->sk_rcvbuf;
+ return READ_ONCE(sk->sk_rcvbuf);
diff --git a/net/x25/x25_dev.c b/net/x25/x25_dev.c
index 5c111bc3c8ea..00e782335cb0 100644
--- a/net/x25/x25_dev.c
+++ b/net/x25/x25_dev.c
@@ -55,7 +55,7 @@ static int x25_receive_data(struct sk_buff *skb, struct x25_neigh *nb)
if (!sock_owned_by_user(sk)) {
queued = x25_process_rx_frame(sk, skb);
} else {
- queued = !sk_add_backlog(sk, skb, sk->sk_rcvbuf);
+ queued = !sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf));