net/smc: fix sleep bug in smc_pnet_find_roce_resource()

Tests showed this BUG:
[572555.252867] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:935
[572555.252876] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 131031, name: smcapp
[572555.252879] INFO: lockdep is turned off.
[572555.252883] CPU: 1 PID: 131031 Comm: smcapp Tainted: G           O      5.7.0-rc3uschi+ #356
[572555.252885] Hardware name: IBM 3906 M03 703 (LPAR)
[572555.252887] Call Trace:
[572555.252896]  [<00000000ac364554>] show_stack+0x94/0xe8
[572555.252901]  [<00000000aca1f400>] dump_stack+0xa0/0xe0
[572555.252906]  [<00000000ac3c8c10>] ___might_sleep+0x260/0x280
[572555.252910]  [<00000000acdc0c98>] __mutex_lock+0x48/0x940
[572555.252912]  [<00000000acdc15c2>] mutex_lock_nested+0x32/0x40
[572555.252975]  [<000003ff801762d0>] mlx5_lag_get_roce_netdev+0x30/0xc0 [mlx5_core]
[572555.252996]  [<000003ff801fb3aa>] mlx5_ib_get_netdev+0x3a/0xe0 [mlx5_ib]
[572555.253007]  [<000003ff80063848>] smc_pnet_find_roce_resource+0x1d8/0x310 [smc]
[572555.253011]  [<000003ff800602f0>] __smc_connect+0x1f0/0x3e0 [smc]
[572555.253015]  [<000003ff80060634>] smc_connect+0x154/0x190 [smc]
[572555.253022]  [<00000000acbed8d4>] __sys_connect+0x94/0xd0
[572555.253025]  [<00000000acbef620>] __s390x_sys_socketcall+0x170/0x360
[572555.253028]  [<00000000acdc6800>] system_call+0x298/0x2b8
[572555.253030] INFO: lockdep is turned off.

Function smc_pnet_find_rdma_dev() might be called from
smc_pnet_find_roce_resource(). It holds the smc_ib_devices list
spinlock while calling infiniband op get_netdev(). At least for mlx5
the get_netdev operation wants mutex serialization, which conflicts
with the smc_ib_devices spinlock.
This patch switches the smc_ib_devices spinlock into a mutex to
allow sleeping when calling get_netdev().

Fixes: d9c6f0576232 ("smc: introduce SMC as an IB-client")
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c
index d695ce71837e61f0e707ecf6ff5fb9900eafd0ae..8bf34d9f27e55cf4a06d96c4f453ff759cc75862 100644 (file)
--- a/net/smc/smc_core.c
+++ b/net/smc/smc_core.c
@@ -15,6 +15,7 @@
 #include <linux/workqueue.h>
 #include <linux/wait.h>
 #include <linux/reboot.h>
+#include <linux/mutex.h>
 #include <net/tcp.h>
 #include <net/sock.h>
 #include <rdma/ib_verbs.h>
@@ -1961,14 +1962,14 @@ static void smc_core_going_away(void)
        struct smc_ib_device *smcibdev;
        struct smcd_dev *smcd;
 
-       spin_lock(&smc_ib_devices.lock);
+       mutex_lock(&smc_ib_devices.mutex);
        list_for_each_entry(smcibdev, &smc_ib_devices.list, list) {
                int i;
 
                for (i = 0; i < SMC_MAX_PORTS; i++)
                        set_bit(i, smcibdev->ports_going_away);
        }
-       spin_unlock(&smc_ib_devices.lock);
+       mutex_unlock(&smc_ib_devices.mutex);
 
        spin_lock(&smcd_dev_list.lock);
        list_for_each_entry(smcd, &smcd_dev_list.list, list) {

diff --git a/net/smc/smc_ib.c b/net/smc/smc_ib.c
index 562a52d01ad161749cb9bbd5a9398416bd292e55..7637fdebbb78f7b7d02ec94cac800c765d54ad04 100644 (file)
--- a/net/smc/smc_ib.c
+++ b/net/smc/smc_ib.c
@@ -16,6 +16,7 @@
 #include <linux/workqueue.h>
 #include <linux/scatterlist.h>
 #include <linux/wait.h>
+#include <linux/mutex.h>
 #include <rdma/ib_verbs.h>
 #include <rdma/ib_cache.h>
 
@@ -33,7 +34,7 @@
 #define SMC_QP_RNR_RETRY                       7 /* 7: infinite */
 
 struct smc_ib_devices smc_ib_devices = {       /* smc-registered ib devices */
-       .lock = __SPIN_LOCK_UNLOCKED(smc_ib_devices.lock),
+       .mutex = __MUTEX_INITIALIZER(smc_ib_devices.mutex),
        .list = LIST_HEAD_INIT(smc_ib_devices.list),
 };
 
@@ -565,9 +566,9 @@ static int smc_ib_add_dev(struct ib_device *ibdev)
        INIT_WORK(&smcibdev->port_event_work, smc_ib_port_event_work);
        atomic_set(&smcibdev->lnk_cnt, 0);
        init_waitqueue_head(&smcibdev->lnks_deleted);
-       spin_lock(&smc_ib_devices.lock);
+       mutex_lock(&smc_ib_devices.mutex);
        list_add_tail(&smcibdev->list, &smc_ib_devices.list);
-       spin_unlock(&smc_ib_devices.lock);
+       mutex_unlock(&smc_ib_devices.mutex);
        ib_set_client_data(ibdev, &smc_ib_client, smcibdev);
        INIT_IB_EVENT_HANDLER(&smcibdev->event_handler, smcibdev->ibdev,
                              smc_ib_global_event_handler);
@@ -602,9 +603,9 @@ static void smc_ib_remove_dev(struct ib_device *ibdev, void *client_data)
 {
        struct smc_ib_device *smcibdev = client_data;
 
-       spin_lock(&smc_ib_devices.lock);
+       mutex_lock(&smc_ib_devices.mutex);
        list_del_init(&smcibdev->list); /* remove from smc_ib_devices */
-       spin_unlock(&smc_ib_devices.lock);
+       mutex_unlock(&smc_ib_devices.mutex);
        pr_warn_ratelimited("smc: removing ib device %s\n",
                            smcibdev->ibdev->name);
        smc_smcr_terminate_all(smcibdev);

diff --git a/net/smc/smc_ib.h b/net/smc/smc_ib.h
index e6a696ae15f3e51fe1d72ab8f0c271324532aecb..ae6776e1e7264ae25590b8a1d643a09ad915bf87 100644 (file)
--- a/net/smc/smc_ib.h
+++ b/net/smc/smc_ib.h
@@ -14,6 +14,7 @@
 
 #include <linux/interrupt.h>
 #include <linux/if_ether.h>
+#include <linux/mutex.h>
 #include <linux/wait.h>
 #include <rdma/ib_verbs.h>
 #include <net/smc.h>
@@ -25,7 +26,7 @@
 
 struct smc_ib_devices {                        /* list of smc ib devices definition */
        struct list_head        list;
-       spinlock_t              lock;   /* protects list of smc ib devices */
+       struct mutex            mutex;  /* protects list of smc ib devices */
 };
 
 extern struct smc_ib_devices   smc_ib_devices; /* list of smc ib devices */

diff --git a/net/smc/smc_pnet.c b/net/smc/smc_pnet.c
index 014d91b9778ec4ba5f701080b7ca64b3bf236c60..d4aac31d39f5a7c386bcb055527604e89cce0562 100644 (file)
--- a/net/smc/smc_pnet.c
+++ b/net/smc/smc_pnet.c
@@ -12,6 +12,7 @@
 #include <linux/module.h>
 #include <linux/list.h>
 #include <linux/ctype.h>
+#include <linux/mutex.h>
 #include <net/netlink.h>
 #include <net/genetlink.h>
 
@@ -129,7 +130,7 @@ static int smc_pnet_remove_by_pnetid(struct net *net, char *pnet_name)
                return rc;
 
        /* remove ib devices */
-       spin_lock(&smc_ib_devices.lock);
+       mutex_lock(&smc_ib_devices.mutex);
        list_for_each_entry(ibdev, &smc_ib_devices.list, list) {
                for (ibport = 0; ibport < SMC_MAX_PORTS; ibport++) {
                        if (ibdev->pnetid_by_user[ibport] &&
@@ -149,7 +150,7 @@ static int smc_pnet_remove_by_pnetid(struct net *net, char *pnet_name)
                        }
                }
        }
-       spin_unlock(&smc_ib_devices.lock);
+       mutex_unlock(&smc_ib_devices.mutex);
        /* remove smcd devices */
        spin_lock(&smcd_dev_list.lock);
        list_for_each_entry(smcd_dev, &smcd_dev_list.list, list) {
@@ -240,14 +241,14 @@ static bool smc_pnet_apply_ib(struct smc_ib_device *ib_dev, u8 ib_port,
        u8 pnet_null[SMC_MAX_PNETID_LEN] = {0};
        bool applied = false;
 
-       spin_lock(&smc_ib_devices.lock);
+       mutex_lock(&smc_ib_devices.mutex);
        if (smc_pnet_match(ib_dev->pnetid[ib_port - 1], pnet_null)) {
                memcpy(ib_dev->pnetid[ib_port - 1], pnet_name,
                       SMC_MAX_PNETID_LEN);
                ib_dev->pnetid_by_user[ib_port - 1] = true;
                applied = true;
        }
-       spin_unlock(&smc_ib_devices.lock);
+       mutex_unlock(&smc_ib_devices.mutex);
        return applied;
 }
 
@@ -300,7 +301,7 @@ static struct smc_ib_device *smc_pnet_find_ib(char *ib_name)
 {
        struct smc_ib_device *ibdev;
 
-       spin_lock(&smc_ib_devices.lock);
+       mutex_lock(&smc_ib_devices.mutex);
        list_for_each_entry(ibdev, &smc_ib_devices.list, list) {
                if (!strncmp(ibdev->ibdev->name, ib_name,
                             sizeof(ibdev->ibdev->name)) ||
@@ -311,7 +312,7 @@ static struct smc_ib_device *smc_pnet_find_ib(char *ib_name)
        }
        ibdev = NULL;
 out:
-       spin_unlock(&smc_ib_devices.lock);
+       mutex_unlock(&smc_ib_devices.mutex);
        return ibdev;
 }
 
@@ -825,7 +826,7 @@ static void _smc_pnet_find_roce_by_pnetid(u8 *pnet_id,
        int i;
 
        ini->ib_dev = NULL;
-       spin_lock(&smc_ib_devices.lock);
+       mutex_lock(&smc_ib_devices.mutex);
        list_for_each_entry(ibdev, &smc_ib_devices.list, list) {
                if (ibdev == known_dev)
                        continue;
@@ -844,7 +845,7 @@ static void _smc_pnet_find_roce_by_pnetid(u8 *pnet_id,
                }
        }
 out:
-       spin_unlock(&smc_ib_devices.lock);
+       mutex_unlock(&smc_ib_devices.mutex);
 }
 
 /* find alternate roce device with same pnet_id and vlan_id */
@@ -863,7 +864,7 @@ static void smc_pnet_find_rdma_dev(struct net_device *netdev,
 {
        struct smc_ib_device *ibdev;
 
-       spin_lock(&smc_ib_devices.lock);
+       mutex_lock(&smc_ib_devices.mutex);
        list_for_each_entry(ibdev, &smc_ib_devices.list, list) {
                struct net_device *ndev;
                int i;
@@ -888,7 +889,7 @@ static void smc_pnet_find_rdma_dev(struct net_device *netdev,
                        }
                }
        }
-       spin_unlock(&smc_ib_devices.lock);
+       mutex_unlock(&smc_ib_devices.mutex);
 }
 
 /* Determine the corresponding IB device port based on the hardware PNETID.