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 8e6b6aa0579e1..9804e9608a5a0 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); @@ -1503,7 +1503,7 @@ 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); @@ -1520,7 +1520,7 @@ 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);