| Message ID | 726660.1730898202@warthog.procyon.org.uk (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | fc9de52de38f656399d2ce40f7349a6b5f86e787 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] rxrpc: Fix missing locking causing hanging calls | expand |
Fixes: 9d35d880e0e4 ("rxrpc: Move client call connection to the I/O thread")
Reported-by: Marc Dionne <marc.dionne@auristor.com>
Hello: This patch was applied to netdev/net.git (main) by Jakub Kicinski <kuba@kernel.org>: On Wed, 06 Nov 2024 13:03:22 +0000 you wrote: > If a call gets aborted (e.g. because kafs saw a signal) between it being > queued for connection and the I/O thread picking up the call, the abort > will be prioritised over the connection and it will be removed from > local->new_client_calls by rxrpc_disconnect_client_call() without a lock > being held. This may cause other calls on the list to disappear if a race > occurs. > > [...] Here is the summary with links: - [net] rxrpc: Fix missing locking causing hanging calls https://git.kernel.org/netdev/net/c/fc9de52de38f You are awesome, thank you!
diff --git a/include/trace/events/rxrpc.h b/include/trace/events/rxrpc.h index c2f087e90fbe..d03e0bd8c028 100644 --- a/include/trace/events/rxrpc.h +++ b/include/trace/events/rxrpc.h @@ -287,6 +287,7 @@ EM(rxrpc_call_see_input, "SEE input ") \ EM(rxrpc_call_see_release, "SEE release ") \ EM(rxrpc_call_see_userid_exists, "SEE u-exists") \ + EM(rxrpc_call_see_waiting_call, "SEE q-conn ") \ E_(rxrpc_call_see_zap, "SEE zap ") #define rxrpc_txqueue_traces \ diff --git a/net/rxrpc/conn_client.c b/net/rxrpc/conn_client.c index d25bf1cf3670..bb11e8289d6d 100644 --- a/net/rxrpc/conn_client.c +++ b/net/rxrpc/conn_client.c @@ -516,6 +516,7 @@ void rxrpc_connect_client_calls(struct rxrpc_local *local) spin_lock(&local->client_call_lock); list_move_tail(&call->wait_link, &bundle->waiting_calls); + rxrpc_see_call(call, rxrpc_call_see_waiting_call); spin_unlock(&local->client_call_lock); if (rxrpc_bundle_has_space(bundle)) @@ -586,7 +587,10 @@ void rxrpc_disconnect_client_call(struct rxrpc_bundle *bundle, struct rxrpc_call _debug("call is waiting"); ASSERTCMP(call->call_id, ==, 0); ASSERT(!test_bit(RXRPC_CALL_EXPOSED, &call->flags)); + /* May still be on ->new_client_calls. */ + spin_lock(&local->client_call_lock); list_del_init(&call->wait_link); + spin_unlock(&local->client_call_lock); return; }
If a call gets aborted (e.g. because kafs saw a signal) between it being queued for connection and the I/O thread picking up the call, the abort will be prioritised over the connection and it will be removed from local->new_client_calls by rxrpc_disconnect_client_call() without a lock being held. This may cause other calls on the list to disappear if a race occurs. Fix this by taking the client_call_lock when removing a call from whatever list its ->wait_link happens to be on. Signed-off-by: David Howells <dhowells@redhat.com> cc: Marc Dionne <marc.dionne@auristor.com> cc: "David S. Miller" <davem@davemloft.net> cc: Eric Dumazet <edumazet@google.com> cc: Jakub Kicinski <kuba@kernel.org> cc: Paolo Abeni <pabeni@redhat.com> cc: Simon Horman <horms@kernel.org> cc: linux-afs@lists.infradead.org cc: netdev@vger.kernel.org --- include/trace/events/rxrpc.h | 1 + net/rxrpc/conn_client.c | 4 ++++ 2 files changed, 5 insertions(+)