[PATCH 6.7 153/713] inet_diag: annotate data-races around inet_diag_table[]

Sasha Levin
2024-03-24T22:49:51Z

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit e50e10ae5d81ddb41547114bfdc5edc04422f082 ]

inet_diag_lock_handler() reads inet_diag_table[proto] locklessly.

Use READ_ONCE()/WRITE_ONCE() annotations to avoid potential issues.

Fixes: d523a328fb02 ("[INET]: Fix inet_diag dead-lock regression")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/ipv4/inet_diag.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index 7d0e7aaa71e0a..5f7fdbd01cf9b 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -57,7 +57,7 @@ static const struct inet_diag_handler *inet_diag_lock_handler(int proto)
return ERR_PTR(-ENOENT);
}

- if (!inet_diag_table[proto])
+ if (!READ_ONCE(inet_diag_table[proto]))
sock_load_diag_module(AF_INET, proto);

mutex_lock(&inet_diag_table_mutex);
@@ -1419,7 +1419,7 @@ int inet_diag_register(const struct inet_diag_handler *h)
mutex_lock(&inet_diag_table_mutex);
err = -EEXIST;
if (!inet_diag_table[type]) {
- inet_diag_table[type] = h;
+ WRITE_ONCE(inet_diag_table[type], h);
err = 0;
}
mutex_unlock(&inet_diag_table_mutex);
@@ -1436,7 +1436,7 @@ void inet_diag_unregister(const struct inet_diag_handler *h)
return;

mutex_lock(&inet_diag_table_mutex);
- inet_diag_table[type] = NULL;
+ WRITE_ONCE(inet_diag_table[type], NULL);
mutex_unlock(&inet_diag_table_mutex);
}
EXPORT_SYMBOL_GPL(inet_diag_unregister);
--
2.43.0