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authorDavid Howells <dhowells@redhat.com>2018-03-30 21:05:23 +0100
committerDavid Howells <dhowells@redhat.com>2018-03-30 21:05:23 +0100
commitd3be4d244330f7ef53242d8dc1b7f77d105e767f (patch)
tree794c9aeba90ac11e8d6a3109df89ad966adc73f6 /net/rxrpc/call_object.c
parent88f2a8257c9aa7df957b1a79a104f348d60d8027 (diff)
downloadlinux-stericsson-d3be4d244330f7ef53242d8dc1b7f77d105e767f.tar.gz
rxrpc: Fix potential call vs socket/net destruction race
rxrpc_call structs don't pin sockets or network namespaces, but may attempt to access both after their refcount reaches 0 so that they can detach themselves from the network namespace. However, there's no guarantee that the socket still exists at this point (so sock_net(&call->socket->sk) may be invalid) and the namespace may have gone away if the call isn't pinning a peer. Fix this by (a) carrying a net pointer in the rxrpc_call struct and (b) waiting for all calls to be destroyed when the network namespace goes away. This was detected by checker: net/rxrpc/call_object.c:634:57: warning: incorrect type in argument 1 (different address spaces) net/rxrpc/call_object.c:634:57: expected struct sock const *sk net/rxrpc/call_object.c:634:57: got struct sock [noderef] <asn:4>*<noident> Fixes: 2baec2c3f854 ("rxrpc: Support network namespacing") Signed-off-by: David Howells <dhowells@redhat.com>
Diffstat (limited to 'net/rxrpc/call_object.c')
-rw-r--r--net/rxrpc/call_object.c16
1 files changed, 13 insertions, 3 deletions
diff --git a/net/rxrpc/call_object.c b/net/rxrpc/call_object.c
index 85b12c472522..f721c2b7e234 100644
--- a/net/rxrpc/call_object.c
+++ b/net/rxrpc/call_object.c
@@ -103,6 +103,7 @@ struct rxrpc_call *rxrpc_alloc_call(struct rxrpc_sock *rx, gfp_t gfp,
unsigned int debug_id)
{
struct rxrpc_call *call;
+ struct rxrpc_net *rxnet = rxrpc_net(sock_net(&rx->sk));
call = kmem_cache_zalloc(rxrpc_call_jar, gfp);
if (!call)
@@ -153,6 +154,9 @@ struct rxrpc_call *rxrpc_alloc_call(struct rxrpc_sock *rx, gfp_t gfp,
call->cong_cwnd = 2;
call->cong_ssthresh = RXRPC_RXTX_BUFF_SIZE - 1;
+
+ call->rxnet = rxnet;
+ atomic_inc(&rxnet->nr_calls);
return call;
nomem_2:
@@ -222,7 +226,7 @@ struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *rx,
__acquires(&call->user_mutex)
{
struct rxrpc_call *call, *xcall;
- struct rxrpc_net *rxnet = rxrpc_net(sock_net(&rx->sk));
+ struct rxrpc_net *rxnet;
struct rb_node *parent, **pp;
const void *here = __builtin_return_address(0);
int ret;
@@ -272,6 +276,7 @@ struct rxrpc_call *rxrpc_new_client_call(struct rxrpc_sock *rx,
write_unlock(&rx->call_lock);
+ rxnet = call->rxnet;
write_lock(&rxnet->call_lock);
list_add_tail(&call->link, &rxnet->calls);
write_unlock(&rxnet->call_lock);
@@ -617,7 +622,7 @@ void rxrpc_release_calls_on_socket(struct rxrpc_sock *rx)
*/
void rxrpc_put_call(struct rxrpc_call *call, enum rxrpc_call_trace op)
{
- struct rxrpc_net *rxnet;
+ struct rxrpc_net *rxnet = call->rxnet;
const void *here = __builtin_return_address(0);
int n;
@@ -631,7 +636,6 @@ void rxrpc_put_call(struct rxrpc_call *call, enum rxrpc_call_trace op)
ASSERTCMP(call->state, ==, RXRPC_CALL_COMPLETE);
if (!list_empty(&call->link)) {
- rxnet = rxrpc_net(sock_net(&call->socket->sk));
write_lock(&rxnet->call_lock);
list_del_init(&call->link);
write_unlock(&rxnet->call_lock);
@@ -647,11 +651,14 @@ void rxrpc_put_call(struct rxrpc_call *call, enum rxrpc_call_trace op)
static void rxrpc_rcu_destroy_call(struct rcu_head *rcu)
{
struct rxrpc_call *call = container_of(rcu, struct rxrpc_call, rcu);
+ struct rxrpc_net *rxnet = call->rxnet;
rxrpc_put_peer(call->peer);
kfree(call->rxtx_buffer);
kfree(call->rxtx_annotations);
kmem_cache_free(rxrpc_call_jar, call);
+ if (atomic_dec_and_test(&rxnet->nr_calls))
+ wake_up_atomic_t(&rxnet->nr_calls);
}
/*
@@ -716,4 +723,7 @@ void rxrpc_destroy_all_calls(struct rxrpc_net *rxnet)
}
write_unlock(&rxnet->call_lock);
+
+ atomic_dec(&rxnet->nr_calls);
+ wait_on_atomic_t(&rxnet->nr_calls, atomic_t_wait, TASK_UNINTERRUPTIBLE);
}