[PATCH] ipv6: Use local variable for ifa->flags in inet6_fill_ifaddr

From: Zilin Guan
Date: Mon Nov 04 2024 - 08:27:27 EST


Currently, the inet6_fill_ifaddr() function reads the value of ifa->flags
using READ_ONCE() and stores it in the local variable flags. However,
the subsequent call to put_ifaddrmsg() uses ifa->flags again instead of
the already read local variable. This re-read is unnecessary because
no other thread can modify ifa->flags between the initial READ_ONCE()
and the subsequent use in put_ifaddrmsg().

Signed-off-by: Zilin Guan <zilinguan811@xxxxxxxxx>
---
net/ipv6/addrconf.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 94dceac52884..c4b080471b39 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -5143,7 +5143,7 @@ static int inet6_fill_ifaddr(struct sk_buff *skb,
return -EMSGSIZE;

flags = READ_ONCE(ifa->flags);
- put_ifaddrmsg(nlh, ifa->prefix_len, ifa->flags, rt_scope(ifa->scope),
+ put_ifaddrmsg(nlh, ifa->prefix_len, flags, rt_scope(ifa->scope),
ifa->idev->dev->ifindex);

if (args->netnsid >= 0 &&
--
2.34.1