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Commit 0f753435 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Greg Kroah-Hartman
Browse files

tcp: Fix a data-race around sysctl_tcp_notsent_lowat. 



[ Upstream commit 55be873695ed8912eb77ff46d1d1cadf028bd0f3 ]

While reading sysctl_tcp_notsent_lowat, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its reader.

Fixes: c9bee3b7 ("tcp: TCP_NOTSENT_LOWAT socket option")
Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent f197442a

include/net/tcp.h

+1 −1
Original line number Original line Diff line number Diff line
@@ -1876,7 +1876,7 @@ void __tcp_v4_send_check(struct sk_buff *skb, __be32 saddr, __be32 daddr); 
static inline u32 tcp_notsent_lowat(const struct tcp_sock *tp)

static inline u32 tcp_notsent_lowat(const struct tcp_sock *tp)

{

{

	struct net *net = sock_net((struct sock *)tp);

	struct net *net = sock_net((struct sock *)tp);

	return tp->notsent_lowat ?: net->ipv4.sysctl_tcp_notsent_lowat;

	return tp->notsent_lowat ?: READ_ONCE(net->ipv4.sysctl_tcp_notsent_lowat);

}

}





static inline bool tcp_stream_memory_free(const struct sock *sk)

static inline bool tcp_stream_memory_free(const struct sock *sk)