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authorEric Dumazet <edumazet@google.com>2024-05-06 10:28:12 +0000
committerJakub Kicinski <kuba@kernel.org>2024-05-07 16:19:14 -0700
commit1eb2cded45b35816085c1f962933c187d970f9dc (patch)
tree27a26692748d3c69fcd896a10db9bc89c1eb54b5 /net/ipv6
parentfeb8c2b76eb3fae59a1f62451508c98c36db5e3a (diff)
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net: annotate writes on dev->mtu from ndo_change_mtu()
Simon reported that ndo_change_mtu() methods were never updated to use WRITE_ONCE(dev->mtu, new_mtu) as hinted in commit 501a90c94510 ("inet: protect against too small mtu values.") We read dev->mtu without holding RTNL in many places, with READ_ONCE() annotations. It is time to take care of ndo_change_mtu() methods to use corresponding WRITE_ONCE() Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Simon Horman <horms@kernel.org> Closes: https://lore.kernel.org/netdev/20240505144608.GB67882@kernel.org/ Reviewed-by: Jacob Keller <jacob.e.keller@intel.com> Reviewed-by: Sabrina Dubroca <sd@queasysnail.net> Reviewed-by: Simon Horman <horms@kernel.org> Acked-by: Shannon Nelson <shannon.nelson@amd.com> Link: https://lore.kernel.org/r/20240506102812.3025432-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv6')
-rw-r--r--net/ipv6/ip6_tunnel.c2
-rw-r--r--net/ipv6/ip6_vti.c3
2 files changed, 3 insertions, 2 deletions
diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 5aec79c2af1a..9dee0c127955 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -1746,7 +1746,7 @@ int ip6_tnl_change_mtu(struct net_device *dev, int new_mtu)
if (new_mtu > IP_MAX_MTU - dev->hard_header_len)
return -EINVAL;
}
- dev->mtu = new_mtu;
+ WRITE_ONCE(dev->mtu, new_mtu);
return 0;
}
EXPORT_SYMBOL(ip6_tnl_change_mtu);
diff --git a/net/ipv6/ip6_vti.c b/net/ipv6/ip6_vti.c
index 78344cf3867e..590737c27537 100644
--- a/net/ipv6/ip6_vti.c
+++ b/net/ipv6/ip6_vti.c
@@ -666,7 +666,8 @@ static void vti6_link_config(struct ip6_tnl *t, bool keep_mtu)
dev->flags &= ~IFF_POINTOPOINT;
if (keep_mtu && dev->mtu) {
- dev->mtu = clamp(dev->mtu, dev->min_mtu, dev->max_mtu);
+ WRITE_ONCE(dev->mtu,
+ clamp(dev->mtu, dev->min_mtu, dev->max_mtu));
return;
}