From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: Tue, 10 Oct 2023 19:13:31 +0000 (+0200)
Subject: 6.1-stable patches
X-Git-Tag: v4.14.327~9
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=af13e22e6d43cfdf99a9b8ba54b296fb0935fb30;p=thirdparty%2Fkernel%2Fstable-queue.git

6.1-stable patches

added patches:
	ipv6-remove-one-read_lock-read_unlock-pair-in-rt6_check_neigh.patch
---

diff --git a/queue-6.1/ipv6-remove-one-read_lock-read_unlock-pair-in-rt6_check_neigh.patch b/queue-6.1/ipv6-remove-one-read_lock-read_unlock-pair-in-rt6_check_neigh.patch
new file mode 100644
index 00000000000..896f42dd145
--- /dev/null
+++ b/queue-6.1/ipv6-remove-one-read_lock-read_unlock-pair-in-rt6_check_neigh.patch
@@ -0,0 +1,45 @@
+From c486640aa710ddd06c13a7f7162126e1552e8842 Mon Sep 17 00:00:00 2001
+From: Eric Dumazet <edumazet@google.com>
+Date: Mon, 13 Mar 2023 20:17:32 +0000
+Subject: ipv6: remove one read_lock()/read_unlock() pair in rt6_check_neigh()
+
+From: Eric Dumazet <edumazet@google.com>
+
+commit c486640aa710ddd06c13a7f7162126e1552e8842 upstream.
+
+rt6_check_neigh() uses read_lock() to protect n->nud_state reading.
+
+This seems overkill and causes false sharing.
+
+Signed-off-by: Eric Dumazet <edumazet@google.com>
+Reviewed-by: David Ahern <dsahern@kernel.org>
+Reviewed-by: Martin KaFai Lau <martin.lau@kernel.org>
+Signed-off-by: Jakub Kicinski <kuba@kernel.org>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ net/ipv6/route.c |    8 ++++----
+ 1 file changed, 4 insertions(+), 4 deletions(-)
+
+--- a/net/ipv6/route.c
++++ b/net/ipv6/route.c
+@@ -690,16 +690,16 @@ static enum rt6_nud_state rt6_check_neig
+ 	neigh = __ipv6_neigh_lookup_noref(fib6_nh->fib_nh_dev,
+ 					  &fib6_nh->fib_nh_gw6);
+ 	if (neigh) {
+-		read_lock(&neigh->lock);
+-		if (neigh->nud_state & NUD_VALID)
++		u8 nud_state = READ_ONCE(neigh->nud_state);
++
++		if (nud_state & NUD_VALID)
+ 			ret = RT6_NUD_SUCCEED;
+ #ifdef CONFIG_IPV6_ROUTER_PREF
+-		else if (!(neigh->nud_state & NUD_FAILED))
++		else if (!(nud_state & NUD_FAILED))
+ 			ret = RT6_NUD_SUCCEED;
+ 		else
+ 			ret = RT6_NUD_FAIL_PROBE;
+ #endif
+-		read_unlock(&neigh->lock);
+ 	} else {
+ 		ret = IS_ENABLED(CONFIG_IPV6_ROUTER_PREF) ?
+ 		      RT6_NUD_SUCCEED : RT6_NUD_FAIL_DO_RR;
diff --git a/queue-6.1/series b/queue-6.1/series
index bd999669dae..4b90a016fac 100644
--- a/queue-6.1/series
+++ b/queue-6.1/series
@@ -152,3 +152,4 @@ btrfs-fix-an-error-handling-path-in-btrfs_rename.patch
 btrfs-fix-fscrypt-name-leak-after-failure-to-join-log-transaction.patch
 netlink-remove-the-flex-array-from-struct-nlmsghdr.patch
 btrfs-file_remove_privs-needs-an-exclusive-lock-in-direct-io-write.patch
+ipv6-remove-one-read_lock-read_unlock-pair-in-rt6_check_neigh.patch