Merge branch 'net-data-race-annotations'

Eric Dumazet says:

====================
net: another round of data-race annotations

Series inspired by some syzbot reports, taking care
of 4 socket fields that can be read locklessly.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 20 insertions, 11 deletions

diff --git a/include/net/ip.h b/include/net/ip.h
index 19adacd5ece0..9276cea775cc 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -94,7 +94,7 @@ static inline void ipcm_init_sk(struct ipcm_cookie *ipcm,
 	ipcm_init(ipcm);
 
 	ipcm->sockc.mark = READ_ONCE(inet->sk.sk_mark);
-	ipcm->sockc.tsflags = inet->sk.sk_tsflags;
+	ipcm->sockc.tsflags = READ_ONCE(inet->sk.sk_tsflags);
 	ipcm->oif = READ_ONCE(inet->sk.sk_bound_dev_if);
 	ipcm->addr = inet->inet_saddr;
 	ipcm->protocol = inet->inet_num;
diff --git a/include/net/sock.h b/include/net/sock.h
index 11d503417591..b770261fbdaf 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1053,6 +1053,12 @@ static inline void sk_wmem_queued_add(struct sock *sk, int val)
 	WRITE_ONCE(sk->sk_wmem_queued, sk->sk_wmem_queued + val);
 }
 
+static inline void sk_forward_alloc_add(struct sock *sk, int val)
+{
+	/* Paired with lockless reads of sk->sk_forward_alloc */
+	WRITE_ONCE(sk->sk_forward_alloc, sk->sk_forward_alloc + val);
+}
+
 void sk_stream_write_space(struct sock *sk);
 
 /* OOB backlog add */
@@ -1377,7 +1383,7 @@ static inline int sk_forward_alloc_get(const struct sock *sk)
 	if (sk->sk_prot->forward_alloc_get)
 		return sk->sk_prot->forward_alloc_get(sk);
 #endif
-	return sk->sk_forward_alloc;
+	return READ_ONCE(sk->sk_forward_alloc);
 }
 
 static inline bool __sk_stream_memory_free(const struct sock *sk, int wake)
@@ -1673,14 +1679,14 @@ static inline void sk_mem_charge(struct sock *sk, int size)
 {
 	if (!sk_has_account(sk))
 		return;
-	sk->sk_forward_alloc -= size;
+	sk_forward_alloc_add(sk, -size);
 }
 
 static inline void sk_mem_uncharge(struct sock *sk, int size)
 {
 	if (!sk_has_account(sk))
 		return;
-	sk->sk_forward_alloc += size;
+	sk_forward_alloc_add(sk, size);
 	sk_mem_reclaim(sk);
 }
 
@@ -1900,7 +1906,9 @@ struct sockcm_cookie {
 static inline void sockcm_init(struct sockcm_cookie *sockc,
 			       const struct sock *sk)
 {
-	*sockc = (struct sockcm_cookie) { .tsflags = sk->sk_tsflags };
+	*sockc = (struct sockcm_cookie) {
+		.tsflags = READ_ONCE(sk->sk_tsflags)
+	};
 }
 
 int __sock_cmsg_send(struct sock *sk, struct cmsghdr *cmsg,
@@ -2695,9 +2703,9 @@ void __sock_recv_wifi_status(struct msghdr *msg, struct sock *sk,
 static inline void
 sock_recv_timestamp(struct msghdr *msg, struct sock *sk, struct sk_buff *skb)
 {
-	ktime_t kt = skb->tstamp;
 	struct skb_shared_hwtstamps *hwtstamps = skb_hwtstamps(skb);
-
+	u32 tsflags = READ_ONCE(sk->sk_tsflags);
+	ktime_t kt = skb->tstamp;
 	/*
 	 * generate control messages if
 	 * - receive time stamping in software requested
@@ -2705,10 +2713,10 @@ sock_recv_timestamp(struct msghdr *msg, struct sock *sk, struct sk_buff *skb)
 	 * - hardware time stamps available and wanted
 	 */
 	if (sock_flag(sk, SOCK_RCVTSTAMP) ||
-	    (sk->sk_tsflags & SOF_TIMESTAMPING_RX_SOFTWARE) ||
-	    (kt && sk->sk_tsflags & SOF_TIMESTAMPING_SOFTWARE) ||
+	    (tsflags & SOF_TIMESTAMPING_RX_SOFTWARE) ||
+	    (kt && tsflags & SOF_TIMESTAMPING_SOFTWARE) ||
 	    (hwtstamps->hwtstamp &&
-	     (sk->sk_tsflags & SOF_TIMESTAMPING_RAW_HARDWARE)))
+	     (tsflags & SOF_TIMESTAMPING_RAW_HARDWARE)))
 		__sock_recv_timestamp(msg, sk, skb);
 	else
 		sock_write_timestamp(sk, kt);
@@ -2730,7 +2738,8 @@ static inline void sock_recv_cmsgs(struct msghdr *msg, struct sock *sk,
 #define TSFLAGS_ANY	  (SOF_TIMESTAMPING_SOFTWARE			| \
 			   SOF_TIMESTAMPING_RAW_HARDWARE)
 
-	if (sk->sk_flags & FLAGS_RECV_CMSGS || sk->sk_tsflags & TSFLAGS_ANY)
+	if (sk->sk_flags & FLAGS_RECV_CMSGS ||
+	    READ_ONCE(sk->sk_tsflags) & TSFLAGS_ANY)
 		__sock_recv_cmsgs(msg, sk, skb);
 	else if (unlikely(sock_flag(sk, SOCK_TIMESTAMP)))
 		sock_write_timestamp(sk, skb->tstamp);