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Patch "crypto: deadlock between crypto_alg_sem/rtnl_mutex/genl_mutex

PATCH [email protected] 1 participant 1 message Dec 21, 2017

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This is a note to let you know that I've just added the patch titled

crypto: deadlock between crypto_alg_sem/rtnl_mutex/genl_mutex
netlink: Annotate nlk cb_mutex by protocol

to the 3.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
crypto-deadlock-between-crypto_alg_sem-rtnl_mutex-genl_mutex.patch
and it can be found in the queue-3.18 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From foo@baz Thu Dec 21 10:55:04 CET 2017

From: Herbert Xu <[email protected]>
Date: Tue, 14 Mar 2017 18:25:57 +0800
Subject: crypto: deadlock between crypto_alg_sem/rtnl_mutex/genl_mutex

From: Herbert Xu <[email protected]>

[ Upstream commit 8a0f5ccfb33b0b8b51de65b7b3bf342ba10b4fb6 ]

Quoted 3 lines · Dmitry Vyukov

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.

---
 net/netlink/af_netlink.c |   41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)
net/netlink/af_netlink.c +41 -0
@@ -93,6 +93,44 @@ EXPORT_SYMBOL_GPL(nl_table);
 
 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 void netlink_skb_destructor(struct sk_buff *skb);
 
@@ -548,6 +586,9 @@ static int __netlink_create(struct net *
 	} else {
 		nlk->cb_mutex = &nlk->cb_def_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);
 

Patches currently in stable-queue which might be from [email protected] are

queue-3.18/crypto-crypto4xx-increase-context-and-scatter-ring-buffer-elements.patch queue-3.18/crypto-deadlock-between-crypto_alg_sem-rtnl_mutex-genl_mutex.patch