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Commit 50a1d3d0 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Greg Kroah-Hartman
Browse files

tcp: Fix data-races around sysctl_tcp_max_reordering. 



[ Upstream commit a11e5b3e7a59fde1a90b0eaeaa82320495cf8cae ]

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

Fixes: dca145ff ("tcp: allow for bigger reordering level")
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 c64b9981

net/ipv4/tcp_input.c

+2 −2
Original line number Original line Diff line number Diff line
@@ -905,7 +905,7 @@ static void tcp_check_sack_reordering(struct sock *sk, const u32 low_seq, 
			 tp->undo_marker ? tp->undo_retrans : 0);

			 tp->undo_marker ? tp->undo_retrans : 0);

#endif

#endif

		tp->reordering = min_t(u32, (metric + mss - 1) / mss,

		tp->reordering = min_t(u32, (metric + mss - 1) / mss,

				       sock_net(sk)->ipv4.sysctl_tcp_max_reordering);

				       READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_max_reordering));

	}

	}





	/* This exciting event is worth to be remembered. 8) */

	/* This exciting event is worth to be remembered. 8) */
@@ -1886,7 +1886,7 @@ static void tcp_check_reno_reordering(struct sock *sk, const int addend) 
		return;

		return;





	tp->reordering = min_t(u32, tp->packets_out + addend,

	tp->reordering = min_t(u32, tp->packets_out + addend,

			       sock_net(sk)->ipv4.sysctl_tcp_max_reordering);

			       READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_max_reordering));

	tp->reord_seen++;

	tp->reord_seen++;

	NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRENOREORDER);

	NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPRENOREORDER);

}

}