Merge remote-tracking branch 'common/android-4.4-p' into lineage-18.1-caf-msm8998

# By Eric Dumazet (2) and others
# Via Greg Kroah-Hartman
* common/android-4.4-p:
  Linux 4.4.289
  perf/x86: Reset destroy callback on event init failure
  scsi: virtio_scsi: Fix spelling mistake "Unsupport" -> "Unsupported"
  scsi: ses: Fix unsigned comparison with less than zero
  mac80211: Drop frames from invalid MAC address in ad-hoc mode
  netfilter: ip6_tables: zero-initialize fragment offset
  HID: apple: Fix logical maximum and usage maximum of Magic Keyboard JIS
  mm: check VMA flags to avoid invalid PROT_NONE NUMA balancing
  gup: document and work around "COW can break either way" issue
  i40e: fix endless loop under rtnl
  netlink: annotate data races around nlk->bound
  ARM: imx6: disable the GIC CPU interface before calling stby-poweroff sequence
  ptp_pch: Load module automatically if ID matches
  net_sched: fix NULL deref in fifo_set_limit()
  phy: mdio: fix memory leak
  xtensa: call irqchip_init only when CONFIG_USE_OF is selected
  nfsd4: Handle the NFSv4 READDIR 'dircount' hint being zero
  USB: cdc-acm: fix break reporting
  USB: cdc-acm: fix racy tty buffer accesses

Change-Id: I72428b366b3ed4931d8f8e8b38c7842ed48ead22

1 files changed, 10 insertions, 4 deletions

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 8014479bdd8f..715d21f95316 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -558,7 +558,10 @@ static int netlink_insert(struct sock *sk, u32 portid)
 
 	/* We need to ensure that the socket is hashed and visible. */
 	smp_wmb();
-	nlk_sk(sk)->bound = portid;
+	/* Paired with lockless reads from netlink_bind(),
+	 * netlink_connect() and netlink_sendmsg().
+	 */
+	WRITE_ONCE(nlk_sk(sk)->bound, portid);
 
 err:
 	release_sock(sk);
@@ -973,7 +976,8 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr,
 	else if (nlk->ngroups < 8*sizeof(groups))
 		groups &= (1UL << nlk->ngroups) - 1;
 
-	bound = nlk->bound;
+	/* Paired with WRITE_ONCE() in netlink_insert() */
+	bound = READ_ONCE(nlk->bound);
 	if (bound) {
 		/* Ensure nlk->portid is up-to-date. */
 		smp_rmb();
@@ -1053,8 +1057,9 @@ static int netlink_connect(struct socket *sock, struct sockaddr *addr,
 
 	/* No need for barriers here as we return to user-space without
 	 * using any of the bound attributes.
+	 * Paired with WRITE_ONCE() in netlink_insert().
 	 */
-	if (!nlk->bound)
+	if (!READ_ONCE(nlk->bound))
 		err = netlink_autobind(sock);
 
 	if (err == 0) {
@@ -1801,7 +1806,8 @@ static int netlink_sendmsg(struct socket *sock, struct msghdr *msg, size_t len)
 		dst_group = nlk->dst_group;
 	}
 
-	if (!nlk->bound) {
+	/* Paired with WRITE_ONCE() in netlink_insert() */
+	if (!READ_ONCE(nlk->bound)) {
 		err = netlink_autobind(sock);
 		if (err)
 			goto out;