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authorEric Dumazet <edumazet@google.com>2023-08-18 01:51:32 +0000
committerJakub Kicinski <kuba@kernel.org>2023-08-18 19:23:30 -0700
commit76f33296d2e09f63118db78125c95ef56df438e9 (patch)
treefcdfc4cd47f9c05965ba57866a29c55d269ed3e4
parentd44036cad31170da0cb9c728e80743f84267da6e (diff)
sock: annotate data-races around prot->memory_pressure
*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: 4d93df0abd50 ("[SCTP]: Rewrite of sctp buffer management code") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Abel Wu <wuyun.abel@bytedance.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Link: https://lore.kernel.org/r/20230818015132.2699348-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
-rw-r--r--include/net/sock.h7
-rw-r--r--net/sctp/socket.c2
2 files changed, 5 insertions, 4 deletions
diff --git a/include/net/sock.h b/include/net/sock.h
index e3d987b2ef12..690e22139543 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1323,6 +1323,7 @@ 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.
*/
@@ -1423,7 +1424,7 @@ 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)
@@ -1435,7 +1436,7 @@ 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
@@ -1512,7 +1513,7 @@ proto_memory_pressure(struct proto *prot)
{
if (!prot->memory_pressure)
return false;
- return !!*prot->memory_pressure;
+ return !!READ_ONCE(*prot->memory_pressure);
}
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 9388d98aebc0..6da738f60f4b 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -99,7 +99,7 @@ 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);
}