4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <edumazet@xxxxxxxxxx>
[ Upstream commit 0bb4d124d34044179b42a769a0c76f389ae973b6 ]
This field can be read or written without socket lock being held.
Add annotations to avoid load-store tearing.
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
include/net/sock.h | 20 ++++++++++++++++----
1 file changed, 16 insertions(+), 4 deletions(-)
diff --git a/include/net/sock.h b/include/net/sock.h
index 373e34b46a3c9..c0df14e5a0754 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1759,21 +1759,33 @@ static inline void sk_tx_queue_set(struct sock *sk, int tx_queue)
/* sk_tx_queue_mapping accept only upto a 16-bit value */
if (WARN_ON_ONCE((unsigned short)tx_queue >= USHRT_MAX))
return;
- sk->sk_tx_queue_mapping = tx_queue;
+ /* Paired with READ_ONCE() in sk_tx_queue_get() and
+ * other WRITE_ONCE() because socket lock might be not held.
+ */
+ WRITE_ONCE(sk->sk_tx_queue_mapping, tx_queue);
}
#define NO_QUEUE_MAPPING USHRT_MAX
static inline void sk_tx_queue_clear(struct sock *sk)
{
- sk->sk_tx_queue_mapping = NO_QUEUE_MAPPING;
+ /* Paired with READ_ONCE() in sk_tx_queue_get() and
+ * other WRITE_ONCE() because socket lock might be not held.
+ */
+ WRITE_ONCE(sk->sk_tx_queue_mapping, NO_QUEUE_MAPPING);
}
static inline int sk_tx_queue_get(const struct sock *sk)
{
- if (sk && sk->sk_tx_queue_mapping != NO_QUEUE_MAPPING)
- return sk->sk_tx_queue_mapping;
+ if (sk) {
+ /* Paired with WRITE_ONCE() in sk_tx_queue_clear()
+ * and sk_tx_queue_set().
+ */
+ int val = READ_ONCE(sk->sk_tx_queue_mapping);
+ if (val != NO_QUEUE_MAPPING)
+ return val;
+ }
return -1;
}
--
2.42.0
