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Commit 7d6cc691 authored by Eric Dumazet's avatar Eric Dumazet Committed by Greg Kroah-Hartman
Browse files

sock: annotate data-races around prot->memory_pressure 



[ Upstream commit 76f33296d2e09f63118db78125c95ef56df438e9 ]

*prot->memory_pressure is read/writen locklessly, we need
to add proper annotations.

A recent commit added a new race, it is time to audit all accesses.

Fixes: 2d0c88e84e48 ("sock: Fix misuse of sk_under_memory_pressure()")
Fixes: 4d93df0a ("[SCTP]: Rewrite of sctp buffer management code")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Abel Wu <wuyun.abel@bytedance.com>
Reviewed-by: default avatarShakeel Butt <shakeelb@google.com>
Link: https://lore.kernel.org/r/20230818015132.2699348-1-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent d28ea7ac

include/net/sock.h

+4 −3
Original line number Diff line number Diff line
@@ -1161,6 +1161,7 @@ struct proto { 
	/*

	 * Pressure flag: try to collapse.

	 * Technical note: it is used by multiple contexts non atomically.

	 * Make sure to use READ_ONCE()/WRITE_ONCE() for all reads/writes.

	 * All the __sk_mem_schedule() is of this nature: accounting

	 * is strict, actions are advisory and have some latency.

	 */
@@ -1277,7 +1278,7 @@ static inline bool sk_has_memory_pressure(const struct sock *sk) 
static inline bool sk_under_global_memory_pressure(const struct sock *sk)

{

	return sk->sk_prot->memory_pressure &&

		!!*sk->sk_prot->memory_pressure;

		!!READ_ONCE(*sk->sk_prot->memory_pressure);

}



static inline bool sk_under_memory_pressure(const struct sock *sk)
@@ -1289,7 +1290,7 @@ static inline bool sk_under_memory_pressure(const struct sock *sk) 
	    mem_cgroup_under_socket_pressure(sk->sk_memcg))

		return true;



	return !!*sk->sk_prot->memory_pressure;

	return !!READ_ONCE(*sk->sk_prot->memory_pressure);

}



static inline long
@@ -1343,7 +1344,7 @@ proto_memory_pressure(struct proto *prot) 
{

	if (!prot->memory_pressure)

		return false;

	return !!*prot->memory_pressure;

	return !!READ_ONCE(*prot->memory_pressure);

}

net/sctp/socket.c

+1 −1
Original line number Diff line number Diff line
@@ -97,7 +97,7 @@ struct percpu_counter sctp_sockets_allocated; 


static void sctp_enter_memory_pressure(struct sock *sk)

{

	sctp_memory_pressure = 1;

	WRITE_ONCE(sctp_memory_pressure, 1);

}