Commit 8a0f5ccf authored by Herbert Xu's avatar Herbert Xu Committed by David S. Miller

crypto: deadlock between crypto_alg_sem/rtnl_mutex/genl_mutex

On Tue, Mar 14, 2017 at 10:44:10AM +0100, Dmitry Vyukov wrote:
>
> Yes, please.
> Disregarding some reports is not a good way long term.

Please try this patch.

---8<---
Subject: netlink: Annotate nlk cb_mutex by protocol

Currently all occurences of nlk->cb_mutex are annotated by lockdep
as a single class.  This causes a false lcokdep cycle involving
genl and crypto_user.

This patch fixes it by dividing cb_mutex into individual classes
based on the netlink protocol.  As genl and crypto_user do not
use the same netlink protocol this breaks the false dependency
loop.
Reported-by: default avatarDmitry Vyukov <dvyukov@google.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 98d068ab
...@@ -96,6 +96,44 @@ EXPORT_SYMBOL_GPL(nl_table); ...@@ -96,6 +96,44 @@ EXPORT_SYMBOL_GPL(nl_table);
static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait); static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);
static struct lock_class_key nlk_cb_mutex_keys[MAX_LINKS];
static const char *const nlk_cb_mutex_key_strings[MAX_LINKS + 1] = {
"nlk_cb_mutex-ROUTE",
"nlk_cb_mutex-1",
"nlk_cb_mutex-USERSOCK",
"nlk_cb_mutex-FIREWALL",
"nlk_cb_mutex-SOCK_DIAG",
"nlk_cb_mutex-NFLOG",
"nlk_cb_mutex-XFRM",
"nlk_cb_mutex-SELINUX",
"nlk_cb_mutex-ISCSI",
"nlk_cb_mutex-AUDIT",
"nlk_cb_mutex-FIB_LOOKUP",
"nlk_cb_mutex-CONNECTOR",
"nlk_cb_mutex-NETFILTER",
"nlk_cb_mutex-IP6_FW",
"nlk_cb_mutex-DNRTMSG",
"nlk_cb_mutex-KOBJECT_UEVENT",
"nlk_cb_mutex-GENERIC",
"nlk_cb_mutex-17",
"nlk_cb_mutex-SCSITRANSPORT",
"nlk_cb_mutex-ECRYPTFS",
"nlk_cb_mutex-RDMA",
"nlk_cb_mutex-CRYPTO",
"nlk_cb_mutex-SMC",
"nlk_cb_mutex-23",
"nlk_cb_mutex-24",
"nlk_cb_mutex-25",
"nlk_cb_mutex-26",
"nlk_cb_mutex-27",
"nlk_cb_mutex-28",
"nlk_cb_mutex-29",
"nlk_cb_mutex-30",
"nlk_cb_mutex-31",
"nlk_cb_mutex-MAX_LINKS"
};
static int netlink_dump(struct sock *sk); static int netlink_dump(struct sock *sk);
static void netlink_skb_destructor(struct sk_buff *skb); static void netlink_skb_destructor(struct sk_buff *skb);
...@@ -585,6 +623,9 @@ static int __netlink_create(struct net *net, struct socket *sock, ...@@ -585,6 +623,9 @@ static int __netlink_create(struct net *net, struct socket *sock,
} else { } else {
nlk->cb_mutex = &nlk->cb_def_mutex; nlk->cb_mutex = &nlk->cb_def_mutex;
mutex_init(nlk->cb_mutex); mutex_init(nlk->cb_mutex);
lockdep_set_class_and_name(nlk->cb_mutex,
nlk_cb_mutex_keys + protocol,
nlk_cb_mutex_key_strings[protocol]);
} }
init_waitqueue_head(&nlk->wait); init_waitqueue_head(&nlk->wait);
......
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