Merge tag 'v5.14-rc4' into media_tree

Linux 5.14-rc4

* tag 'v5.14-rc4': (948 commits)
  Linux 5.14-rc4
  pipe: make pipe writes always wake up readers
  Revert "perf map: Fix dso->nsinfo refcounting"
  mm/memcg: fix NULL pointer dereference in memcg_slab_free_hook()
  slub: fix unreclaimable slab stat for bulk free
  mm/migrate: fix NR_ISOLATED corruption on 64-bit
  mm: memcontrol: fix blocking rstat function called from atomic cgroup1 thresholding code
  ocfs2: issue zeroout to EOF blocks
  ocfs2: fix zero out valid data
  lib/test_string.c: move string selftest in the Runtime Testing menu
  gve: Update MAINTAINERS list
  arch: Kconfig: clean up obsolete use of HAVE_IDE
  can: esd_usb2: fix memory leak
  can: ems_usb: fix memory leak
  can: usb_8dev: fix memory leak
  can: mcba_usb_start(): add missing urb->transfer_dma initialization
  can: hi311x: fix a signedness bug in hi3110_cmd()
  MAINTAINERS: add Yasushi SHOJI as reviewer for the Microchip CAN BUS Analyzer Tool driver
  scsi: fas216: Fix fall-through warning for Clang
  scsi: acornscsi: Fix fall-through warning for clang
  ...

1 files changed, 24 insertions, 4 deletions

diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c
index 47c32604d38f..25fa4c01a17f 100644
--- a/net/ipv4/tcp_fastopen.c
+++ b/net/ipv4/tcp_fastopen.c
@@ -507,8 +507,18 @@ void tcp_fastopen_active_disable(struct sock *sk)
 {
 	struct net *net = sock_net(sk);
 
+	if (!sock_net(sk)->ipv4.sysctl_tcp_fastopen_blackhole_timeout)
+		return;
+
+	/* Paired with READ_ONCE() in tcp_fastopen_active_should_disable() */
+	WRITE_ONCE(net->ipv4.tfo_active_disable_stamp, jiffies);
+
+	/* Paired with smp_rmb() in tcp_fastopen_active_should_disable().
+	 * We want net->ipv4.tfo_active_disable_stamp to be updated first.
+	 */
+	smp_mb__before_atomic();
 	atomic_inc(&net->ipv4.tfo_active_disable_times);
-	net->ipv4.tfo_active_disable_stamp = jiffies;
+
 	NET_INC_STATS(net, LINUX_MIB_TCPFASTOPENBLACKHOLE);
 }
 
@@ -519,17 +529,27 @@ void tcp_fastopen_active_disable(struct sock *sk)
 bool tcp_fastopen_active_should_disable(struct sock *sk)
 {
 	unsigned int tfo_bh_timeout = sock_net(sk)->ipv4.sysctl_tcp_fastopen_blackhole_timeout;
-	int tfo_da_times = atomic_read(&sock_net(sk)->ipv4.tfo_active_disable_times);
 	unsigned long timeout;
+	int tfo_da_times;
 	int multiplier;
 
+	if (!tfo_bh_timeout)
+		return false;
+
+	tfo_da_times = atomic_read(&sock_net(sk)->ipv4.tfo_active_disable_times);
 	if (!tfo_da_times)
 		return false;
 
+	/* Paired with smp_mb__before_atomic() in tcp_fastopen_active_disable() */
+	smp_rmb();
+
 	/* Limit timeout to max: 2^6 * initial timeout */
 	multiplier = 1 << min(tfo_da_times - 1, 6);
-	timeout = multiplier * tfo_bh_timeout * HZ;
-	if (time_before(jiffies, sock_net(sk)->ipv4.tfo_active_disable_stamp + timeout))
+
+	/* Paired with the WRITE_ONCE() in tcp_fastopen_active_disable(). */
+	timeout = READ_ONCE(sock_net(sk)->ipv4.tfo_active_disable_stamp) +
+		  multiplier * tfo_bh_timeout * HZ;
+	if (time_before(jiffies, timeout))
 		return true;
 
 	/* Mark check bit so we can check for successful active TFO