From 082bb94fe18e54cc64026a623d94ed6bc7242a5f Mon Sep 17 00:00:00 2001 From: Manivannan Sadhasivam Date: Mon, 5 Oct 2020 12:46:42 +0530 Subject: net: qrtr: ns: Fix the incorrect usage of rcu_read_lock() The rcu_read_lock() is not supposed to lock the kernel_sendmsg() API since it has the lock_sock() in qrtr_sendmsg() which will sleep. Hence, fix it by excluding the locking for kernel_sendmsg(). While at it, let's also use radix_tree_deref_retry() to confirm the validity of the pointer returned by radix_tree_deref_slot() and use radix_tree_iter_resume() to resume iterating the tree properly before releasing the lock as suggested by Doug. Fixes: a7809ff90ce6 ("net: qrtr: ns: Protect radix_tree_deref_slot() using rcu read locks") Reported-by: Douglas Anderson Reviewed-by: Douglas Anderson Tested-by: Douglas Anderson Tested-by: Alex Elder Signed-off-by: Manivannan Sadhasivam Signed-off-by: David S. Miller --- net/qrtr/ns.c | 76 +++++++++++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 64 insertions(+), 12 deletions(-) (limited to 'net') diff --git a/net/qrtr/ns.c b/net/qrtr/ns.c index 934999b56d60..b8559c882431 100644 --- a/net/qrtr/ns.c +++ b/net/qrtr/ns.c @@ -193,7 +193,7 @@ static int announce_servers(struct sockaddr_qrtr *sq) struct qrtr_server *srv; struct qrtr_node *node; void __rcu **slot; - int ret = 0; + int ret; node = node_get(qrtr_ns.local_node); if (!node) @@ -203,18 +203,27 @@ static int announce_servers(struct sockaddr_qrtr *sq) /* Announce the list of servers registered in this node */ radix_tree_for_each_slot(slot, &node->servers, &iter, 0) { srv = radix_tree_deref_slot(slot); + if (!srv) + continue; + if (radix_tree_deref_retry(srv)) { + slot = radix_tree_iter_retry(&iter); + continue; + } + slot = radix_tree_iter_resume(slot, &iter); + rcu_read_unlock(); ret = service_announce_new(sq, srv); if (ret < 0) { pr_err("failed to announce new service\n"); - goto err_out; + return ret; } + + rcu_read_lock(); } -err_out: rcu_read_unlock(); - return ret; + return 0; } static struct qrtr_server *server_add(unsigned int service, @@ -339,7 +348,7 @@ static int ctrl_cmd_bye(struct sockaddr_qrtr *from) struct qrtr_node *node; void __rcu **slot; struct kvec iv; - int ret = 0; + int ret; iv.iov_base = &pkt; iv.iov_len = sizeof(pkt); @@ -352,7 +361,16 @@ static int ctrl_cmd_bye(struct sockaddr_qrtr *from) /* Advertise removal of this client to all servers of remote node */ radix_tree_for_each_slot(slot, &node->servers, &iter, 0) { srv = radix_tree_deref_slot(slot); + if (!srv) + continue; + if (radix_tree_deref_retry(srv)) { + slot = radix_tree_iter_retry(&iter); + continue; + } + slot = radix_tree_iter_resume(slot, &iter); + rcu_read_unlock(); server_del(node, srv->port); + rcu_read_lock(); } rcu_read_unlock(); @@ -368,6 +386,14 @@ static int ctrl_cmd_bye(struct sockaddr_qrtr *from) rcu_read_lock(); radix_tree_for_each_slot(slot, &local_node->servers, &iter, 0) { srv = radix_tree_deref_slot(slot); + if (!srv) + continue; + if (radix_tree_deref_retry(srv)) { + slot = radix_tree_iter_retry(&iter); + continue; + } + slot = radix_tree_iter_resume(slot, &iter); + rcu_read_unlock(); sq.sq_family = AF_QIPCRTR; sq.sq_node = srv->node; @@ -379,14 +405,14 @@ static int ctrl_cmd_bye(struct sockaddr_qrtr *from) ret = kernel_sendmsg(qrtr_ns.sock, &msg, &iv, 1, sizeof(pkt)); if (ret < 0) { pr_err("failed to send bye cmd\n"); - goto err_out; + return ret; } + rcu_read_lock(); } -err_out: rcu_read_unlock(); - return ret; + return 0; } static int ctrl_cmd_del_client(struct sockaddr_qrtr *from, @@ -404,7 +430,7 @@ static int ctrl_cmd_del_client(struct sockaddr_qrtr *from, struct list_head *li; void __rcu **slot; struct kvec iv; - int ret = 0; + int ret; iv.iov_base = &pkt; iv.iov_len = sizeof(pkt); @@ -447,6 +473,14 @@ static int ctrl_cmd_del_client(struct sockaddr_qrtr *from, rcu_read_lock(); radix_tree_for_each_slot(slot, &local_node->servers, &iter, 0) { srv = radix_tree_deref_slot(slot); + if (!srv) + continue; + if (radix_tree_deref_retry(srv)) { + slot = radix_tree_iter_retry(&iter); + continue; + } + slot = radix_tree_iter_resume(slot, &iter); + rcu_read_unlock(); sq.sq_family = AF_QIPCRTR; sq.sq_node = srv->node; @@ -458,14 +492,14 @@ static int ctrl_cmd_del_client(struct sockaddr_qrtr *from, ret = kernel_sendmsg(qrtr_ns.sock, &msg, &iv, 1, sizeof(pkt)); if (ret < 0) { pr_err("failed to send del client cmd\n"); - goto err_out; + return ret; } + rcu_read_lock(); } -err_out: rcu_read_unlock(); - return ret; + return 0; } static int ctrl_cmd_new_server(struct sockaddr_qrtr *from, @@ -571,16 +605,34 @@ static int ctrl_cmd_new_lookup(struct sockaddr_qrtr *from, rcu_read_lock(); radix_tree_for_each_slot(node_slot, &nodes, &node_iter, 0) { node = radix_tree_deref_slot(node_slot); + if (!node) + continue; + if (radix_tree_deref_retry(node)) { + node_slot = radix_tree_iter_retry(&node_iter); + continue; + } + node_slot = radix_tree_iter_resume(node_slot, &node_iter); radix_tree_for_each_slot(srv_slot, &node->servers, &srv_iter, 0) { struct qrtr_server *srv; srv = radix_tree_deref_slot(srv_slot); + if (!srv) + continue; + if (radix_tree_deref_retry(srv)) { + srv_slot = radix_tree_iter_retry(&srv_iter); + continue; + } + if (!server_match(srv, &filter)) continue; + srv_slot = radix_tree_iter_resume(srv_slot, &srv_iter); + + rcu_read_unlock(); lookup_notify(from, srv, true); + rcu_read_lock(); } } rcu_read_unlock(); -- cgit