From: Zhengchuan Liang `caif_connect()` can tear down an existing client after remote shutdown by calling `caif_disconnect_client()` followed by `caif_free_client()`. `caif_free_client()` releases the service layer referenced by `adap_layer->dn`, but leaves that pointer stale. When the socket is later destroyed, `caif_sock_destructor()` calls `caif_free_client()` again and dereferences the freed service pointer. Clear the client/service links before releasing the service object so repeated teardown becomes harmless. Fixes: 43e369210108 ("caif: Move refcount from service layer to sock and dev.") Cc: stable@kernel.org Reported-by: Yifan Wu Reported-by: Juefei Pu Co-developed-by: Yuan Tan Signed-off-by: Yuan Tan Suggested-by: Xin Liu Tested-by: Ren Wei Signed-off-by: Zhengchuan Liang Signed-off-by: Ren Wei --- net/caif/cfsrvl.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/net/caif/cfsrvl.c b/net/caif/cfsrvl.c index 171fa32ada85c..d687fd0b4ed3a 100644 --- a/net/caif/cfsrvl.c +++ b/net/caif/cfsrvl.c @@ -191,10 +191,20 @@ bool cfsrvl_phyid_match(struct cflayer *layer, int phyid) void caif_free_client(struct cflayer *adap_layer) { + struct cflayer *serv_layer; struct cfsrvl *servl; - if (adap_layer == NULL || adap_layer->dn == NULL) + + if (!adap_layer) + return; + + serv_layer = adap_layer->dn; + if (!serv_layer) return; - servl = container_obj(adap_layer->dn); + + layer_set_dn(adap_layer, NULL); + layer_set_up(serv_layer, NULL); + + servl = container_obj(serv_layer); servl->release(&servl->layer); } EXPORT_SYMBOL(caif_free_client); -- 2.43.0