FAILED: patch "[PATCH] net/smc: Use a mutex for locking "struct smc_pnettable"" failed to apply to 5.4-stable tree

PATCH [email protected] 1 participant 1 message Feb 25, 2022

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Networking Stable branch Shared memory communications (SMC) sockets

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2022-02-25 15:46 UTC #0 lore raw

The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 7ff57e98fb78ad94edafbdc7435f2d745e9e6bb5 Mon Sep 17 00:00:00 2001
From: "Fabio M. De Francesco" <[email protected]>
Date: Wed, 23 Feb 2022 11:02:52 +0100
Subject: [PATCH] net/smc: Use a mutex for locking "struct smc_pnettable"

smc_pnetid_by_table_ib() uses read_lock() and then it calls smc_pnet_apply_ib() which, in turn, calls mutex_lock(&smc_ib_devices.mutex).

read_lock() disables preemption. Therefore, the code acquires a mutex while in atomic context and it leads to a SAC bug.

Fix this bug by replacing the rwlock with a mutex.

Reported-and-tested-by [email protected]

Fixes 64e28b52c7a6 ("net/smc: add pnet table namespace support")

Confirmed-by Tony Lu <[email protected]>

Signed-off-by Fabio M. De Francesco <[email protected]>

Acked-by Karsten Graul <[email protected]>

Link https://lore.kernel.org/r/[email protected] open here

Signed-off-by Jakub Kicinski <[email protected]>

net/smc/smc_pnet.c +21 ~~-21~~

index 0599246c0376..29f0a559d884 100644
@@ -113,7 +113,7 @@ static int smc_pnet_remove_by_pnetid(struct net *net, char *pnet_name)
 	pnettable = &sn->pnettable;
 
 	/* remove table entry */
-	write_lock(&pnettable->lock);
+	mutex_lock(&pnettable->lock);
 	list_for_each_entry_safe(pnetelem, tmp_pe, &pnettable->pnetlist,
 				 list) {
 		if (!pnet_name ||

@@ -131,7 +131,7 @@ static int smc_pnet_remove_by_pnetid(struct net *net, char *pnet_name)
 			rc = 0;
 		}
 	}
-	write_unlock(&pnettable->lock);
+	mutex_unlock(&pnettable->lock);
 
 	/* if this is not the initial namespace, stop here */
 	if (net != &init_net)

@@ -192,7 +192,7 @@ static int smc_pnet_add_by_ndev(struct net_device *ndev)
 	sn = net_generic(net, smc_net_id);
 	pnettable = &sn->pnettable;
 
-	write_lock(&pnettable->lock);
+	mutex_lock(&pnettable->lock);
 	list_for_each_entry_safe(pnetelem, tmp_pe, &pnettable->pnetlist, list) {
 		if (pnetelem->type == SMC_PNET_ETH && !pnetelem->ndev &&
 		    !strncmp(pnetelem->eth_name, ndev->name, IFNAMSIZ)) {

@@ -206,7 +206,7 @@ static int smc_pnet_add_by_ndev(struct net_device *ndev)
 			break;
 		}
 	}
-	write_unlock(&pnettable->lock);
+	mutex_unlock(&pnettable->lock);
 	return rc;
 }

@@ -224,7 +224,7 @@ static int smc_pnet_remove_by_ndev(struct net_device *ndev)
 	sn = net_generic(net, smc_net_id);
 	pnettable = &sn->pnettable;
 
-	write_lock(&pnettable->lock);
+	mutex_lock(&pnettable->lock);
 	list_for_each_entry_safe(pnetelem, tmp_pe, &pnettable->pnetlist, list) {
 		if (pnetelem->type == SMC_PNET_ETH && pnetelem->ndev == ndev) {
 			dev_put_track(pnetelem->ndev, &pnetelem->dev_tracker);

@@ -237,7 +237,7 @@ static int smc_pnet_remove_by_ndev(struct net_device *ndev)
 			break;
 		}
 	}
-	write_unlock(&pnettable->lock);
+	mutex_unlock(&pnettable->lock);
 	return rc;
 }

@@ -370,7 +370,7 @@ static int smc_pnet_add_eth(struct smc_pnettable *pnettable, struct net *net,
 	strncpy(new_pe->eth_name, eth_name, IFNAMSIZ);
 	rc = -EEXIST;
 	new_netdev = true;
-	write_lock(&pnettable->lock);
+	mutex_lock(&pnettable->lock);
 	list_for_each_entry(tmp_pe, &pnettable->pnetlist, list) {
 		if (tmp_pe->type == SMC_PNET_ETH &&
 		    !strncmp(tmp_pe->eth_name, eth_name, IFNAMSIZ)) {

@@ -385,9 +385,9 @@ static int smc_pnet_add_eth(struct smc_pnettable *pnettable, struct net *net,
 					     GFP_ATOMIC);
 		}
 		list_add_tail(&new_pe->list, &pnettable->pnetlist);
-		write_unlock(&pnettable->lock);
+		mutex_unlock(&pnettable->lock);
 	} else {
-		write_unlock(&pnettable->lock);
+		mutex_unlock(&pnettable->lock);
 		kfree(new_pe);
 		goto out_put;
 	}

@@ -448,7 +448,7 @@ static int smc_pnet_add_ib(struct smc_pnettable *pnettable, char *ib_name,
 	new_pe->ib_port = ib_port;
 
 	new_ibdev = true;
-	write_lock(&pnettable->lock);
+	mutex_lock(&pnettable->lock);
 	list_for_each_entry(tmp_pe, &pnettable->pnetlist, list) {
 		if (tmp_pe->type == SMC_PNET_IB &&
 		    !strncmp(tmp_pe->ib_name, ib_name, IB_DEVICE_NAME_MAX)) {

@@ -458,9 +458,9 @@ static int smc_pnet_add_ib(struct smc_pnettable *pnettable, char *ib_name,
 	}
 	if (new_ibdev) {
 		list_add_tail(&new_pe->list, &pnettable->pnetlist);
-		write_unlock(&pnettable->lock);
+		mutex_unlock(&pnettable->lock);
 	} else {
-		write_unlock(&pnettable->lock);
+		mutex_unlock(&pnettable->lock);
 		kfree(new_pe);
 	}
 	return (new_ibdev) ? 0 : -EEXIST;

@@ -605,7 +605,7 @@ static int _smc_pnet_dump(struct net *net, struct sk_buff *skb, u32 portid,
 	pnettable = &sn->pnettable;
 
 	/* dump pnettable entries */
-	read_lock(&pnettable->lock);
+	mutex_lock(&pnettable->lock);
 	list_for_each_entry(pnetelem, &pnettable->pnetlist, list) {
 		if (pnetid && !smc_pnet_match(pnetelem->pnet_name, pnetid))
 			continue;

@@ -620,7 +620,7 @@ static int _smc_pnet_dump(struct net *net, struct sk_buff *skb, u32 portid,
 			break;
 		}
 	}
-	read_unlock(&pnettable->lock);
+	mutex_unlock(&pnettable->lock);
 	return idx;
 }

@@ -864,7 +864,7 @@ int smc_pnet_net_init(struct net *net)
 	struct smc_pnetids_ndev *pnetids_ndev = &sn->pnetids_ndev;
 
 	INIT_LIST_HEAD(&pnettable->pnetlist);
-	rwlock_init(&pnettable->lock);
+	mutex_init(&pnettable->lock);
 	INIT_LIST_HEAD(&pnetids_ndev->list);
 	rwlock_init(&pnetids_ndev->lock);

@@ -944,7 +944,7 @@ static int smc_pnet_find_ndev_pnetid_by_table(struct net_device *ndev,
 	sn = net_generic(net, smc_net_id);
 	pnettable = &sn->pnettable;
 
-	read_lock(&pnettable->lock);
+	mutex_lock(&pnettable->lock);
 	list_for_each_entry(pnetelem, &pnettable->pnetlist, list) {
 		if (pnetelem->type == SMC_PNET_ETH && ndev == pnetelem->ndev) {
 			/* get pnetid of netdev device */

@@ -953,7 +953,7 @@ static int smc_pnet_find_ndev_pnetid_by_table(struct net_device *ndev,
 			break;
 		}
 	}
-	read_unlock(&pnettable->lock);
+	mutex_unlock(&pnettable->lock);
 	return rc;
 }

@@ -1156,7 +1156,7 @@ int smc_pnetid_by_table_ib(struct smc_ib_device *smcibdev, u8 ib_port)
 	sn = net_generic(&init_net, smc_net_id);
 	pnettable = &sn->pnettable;
 
-	read_lock(&pnettable->lock);
+	mutex_lock(&pnettable->lock);
 	list_for_each_entry(tmp_pe, &pnettable->pnetlist, list) {
 		if (tmp_pe->type == SMC_PNET_IB &&
 		    !strncmp(tmp_pe->ib_name, ib_name, IB_DEVICE_NAME_MAX) &&

@@ -1166,7 +1166,7 @@ int smc_pnetid_by_table_ib(struct smc_ib_device *smcibdev, u8 ib_port)
 			break;
 		}
 	}
-	read_unlock(&pnettable->lock);
+	mutex_unlock(&pnettable->lock);
 
 	return rc;
 }

@@ -1185,7 +1185,7 @@ int smc_pnetid_by_table_smcd(struct smcd_dev *smcddev)
 	sn = net_generic(&init_net, smc_net_id);
 	pnettable = &sn->pnettable;
 
-	read_lock(&pnettable->lock);
+	mutex_lock(&pnettable->lock);
 	list_for_each_entry(tmp_pe, &pnettable->pnetlist, list) {
 		if (tmp_pe->type == SMC_PNET_IB &&
 		    !strncmp(tmp_pe->ib_name, ib_name, IB_DEVICE_NAME_MAX)) {

@@ -1194,7 +1194,7 @@ int smc_pnetid_by_table_smcd(struct smcd_dev *smcddev)
 			break;
 		}
 	}
-	read_unlock(&pnettable->lock);
+	mutex_unlock(&pnettable->lock);
 
 	return rc;
 }

net/smc/smc_pnet.h +1 -1

index 14039272f7e4..80a88eea4949 100644
@@ -29,7 +29,7 @@ struct smc_link_group;
  * @pnetlist: List of PNETIDs
  */
 struct smc_pnettable {
-	rwlock_t lock;
+	struct mutex lock;
 	struct list_head pnetlist;
 };