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author | Julian Wiedmann <jwi@linux.ibm.com> | 2019-11-20 14:20:56 +0100 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2019-11-20 12:29:47 -0800 |
commit | c8183f5489020afc08dd9d88c3e4ee0e3c820733 (patch) | |
tree | eab9d781313d549f49d10f3af84e7ed78f952166 /drivers/s390/net | |
parent | 004b39427f945696db30abb2c4e1a3856ffff819 (diff) | |
download | linux-c8183f5489020afc08dd9d88c3e4ee0e3c820733.tar.gz linux-c8183f5489020afc08dd9d88c3e4ee0e3c820733.tar.bz2 linux-c8183f5489020afc08dd9d88c3e4ee0e3c820733.zip |
s390/qeth: fix potential deadlock on workqueue flush
The L2 bridgeport code uses the coarse 'conf_mutex' for guarding access
to its configuration state.
This can result in a deadlock when qeth_l2_stop_card() - called under the
conf_mutex - blocks on flush_workqueue() to wait for the completion of
pending bridgeport workers. Such workers would also need to aquire
the conf_mutex, stalling indefinitely.
Introduce a lock that specifically guards the bridgeport configuration,
so that the workers no longer need the conf_mutex.
Wrapping qeth_l2_promisc_to_bridge() in this fine-grained lock then also
fixes a theoretical race against a concurrent qeth_bridge_port_role_store()
operation.
Fixes: c0a2e4d10d93 ("s390/qeth: conclude all event processing before offlining a card")
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/s390/net')
-rw-r--r-- | drivers/s390/net/qeth_core.h | 1 | ||||
-rw-r--r-- | drivers/s390/net/qeth_l2_main.c | 21 | ||||
-rw-r--r-- | drivers/s390/net/qeth_l2_sys.c | 14 |
3 files changed, 28 insertions, 8 deletions
diff --git a/drivers/s390/net/qeth_core.h b/drivers/s390/net/qeth_core.h index e4b55f9aa062..65e31df37b1f 100644 --- a/drivers/s390/net/qeth_core.h +++ b/drivers/s390/net/qeth_core.h @@ -839,6 +839,7 @@ struct qeth_card { struct service_level qeth_service_level; struct qdio_ssqd_desc ssqd; debug_info_t *debug; + struct mutex sbp_lock; struct mutex conf_mutex; struct mutex discipline_mutex; struct napi_struct napi; diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c index bd8143e51747..4bccdce19b5a 100644 --- a/drivers/s390/net/qeth_l2_main.c +++ b/drivers/s390/net/qeth_l2_main.c @@ -467,10 +467,14 @@ static void qeth_l2_set_promisc_mode(struct qeth_card *card) if (card->info.promisc_mode == enable) return; - if (qeth_adp_supported(card, IPA_SETADP_SET_PROMISC_MODE)) + if (qeth_adp_supported(card, IPA_SETADP_SET_PROMISC_MODE)) { qeth_setadp_promisc_mode(card, enable); - else if (card->options.sbp.reflect_promisc) - qeth_l2_promisc_to_bridge(card, enable); + } else { + mutex_lock(&card->sbp_lock); + if (card->options.sbp.reflect_promisc) + qeth_l2_promisc_to_bridge(card, enable); + mutex_unlock(&card->sbp_lock); + } } /* New MAC address is added to the hash table and marked to be written on card @@ -631,6 +635,7 @@ static int qeth_l2_probe_device(struct ccwgroup_device *gdev) int rc; qeth_l2_vnicc_set_defaults(card); + mutex_init(&card->sbp_lock); if (gdev->dev.type == &qeth_generic_devtype) { rc = qeth_l2_create_device_attributes(&gdev->dev); @@ -804,10 +809,12 @@ static int qeth_l2_set_online(struct ccwgroup_device *gdev) } else card->info.hwtrap = 0; + mutex_lock(&card->sbp_lock); qeth_bridgeport_query_support(card); if (card->options.sbp.supported_funcs) dev_info(&card->gdev->dev, "The device represents a Bridge Capable Port\n"); + mutex_unlock(&card->sbp_lock); qeth_l2_register_dev_addr(card); @@ -1162,9 +1169,9 @@ static void qeth_bridge_state_change_worker(struct work_struct *work) /* Role should not change by itself, but if it did, */ /* information from the hardware is authoritative. */ - mutex_lock(&data->card->conf_mutex); + mutex_lock(&data->card->sbp_lock); data->card->options.sbp.role = entry->role; - mutex_unlock(&data->card->conf_mutex); + mutex_unlock(&data->card->sbp_lock); snprintf(env_locrem, sizeof(env_locrem), "BRIDGEPORT=statechange"); snprintf(env_role, sizeof(env_role), "ROLE=%s", @@ -1230,9 +1237,9 @@ static void qeth_bridge_host_event_worker(struct work_struct *work) : (data->hostevs.lost_event_mask == 0x02) ? "Bridge port state change" : "Unknown reason"); - mutex_lock(&data->card->conf_mutex); + mutex_lock(&data->card->sbp_lock); data->card->options.sbp.hostnotification = 0; - mutex_unlock(&data->card->conf_mutex); + mutex_unlock(&data->card->sbp_lock); qeth_bridge_emit_host_event(data->card, anev_abort, 0, NULL, NULL); } else diff --git a/drivers/s390/net/qeth_l2_sys.c b/drivers/s390/net/qeth_l2_sys.c index f2c3b127b1e4..e2bcb26105a3 100644 --- a/drivers/s390/net/qeth_l2_sys.c +++ b/drivers/s390/net/qeth_l2_sys.c @@ -24,6 +24,7 @@ static ssize_t qeth_bridge_port_role_state_show(struct device *dev, if (qeth_l2_vnicc_is_in_use(card)) return sprintf(buf, "n/a (VNIC characteristics)\n"); + mutex_lock(&card->sbp_lock); if (qeth_card_hw_is_reachable(card) && card->options.sbp.supported_funcs) rc = qeth_bridgeport_query_ports(card, @@ -57,6 +58,7 @@ static ssize_t qeth_bridge_port_role_state_show(struct device *dev, else rc = sprintf(buf, "%s\n", word); } + mutex_unlock(&card->sbp_lock); return rc; } @@ -91,6 +93,7 @@ static ssize_t qeth_bridge_port_role_store(struct device *dev, return -EINVAL; mutex_lock(&card->conf_mutex); + mutex_lock(&card->sbp_lock); if (qeth_l2_vnicc_is_in_use(card)) rc = -EBUSY; @@ -104,6 +107,7 @@ static ssize_t qeth_bridge_port_role_store(struct device *dev, } else card->options.sbp.role = role; + mutex_unlock(&card->sbp_lock); mutex_unlock(&card->conf_mutex); return rc ? rc : count; @@ -158,6 +162,7 @@ static ssize_t qeth_bridgeport_hostnotification_store(struct device *dev, return rc; mutex_lock(&card->conf_mutex); + mutex_lock(&card->sbp_lock); if (qeth_l2_vnicc_is_in_use(card)) rc = -EBUSY; @@ -168,6 +173,7 @@ static ssize_t qeth_bridgeport_hostnotification_store(struct device *dev, } else card->options.sbp.hostnotification = enable; + mutex_unlock(&card->sbp_lock); mutex_unlock(&card->conf_mutex); return rc ? rc : count; @@ -223,6 +229,7 @@ static ssize_t qeth_bridgeport_reflect_store(struct device *dev, return -EINVAL; mutex_lock(&card->conf_mutex); + mutex_lock(&card->sbp_lock); if (qeth_l2_vnicc_is_in_use(card)) rc = -EBUSY; @@ -234,6 +241,7 @@ static ssize_t qeth_bridgeport_reflect_store(struct device *dev, rc = 0; } + mutex_unlock(&card->sbp_lock); mutex_unlock(&card->conf_mutex); return rc ? rc : count; @@ -269,6 +277,8 @@ void qeth_l2_setup_bridgeport_attrs(struct qeth_card *card) return; if (!card->options.sbp.supported_funcs) return; + + mutex_lock(&card->sbp_lock); if (card->options.sbp.role != QETH_SBP_ROLE_NONE) { /* Conditional to avoid spurious error messages */ qeth_bridgeport_setrole(card, card->options.sbp.role); @@ -280,8 +290,10 @@ void qeth_l2_setup_bridgeport_attrs(struct qeth_card *card) rc = qeth_bridgeport_an_set(card, 1); if (rc) card->options.sbp.hostnotification = 0; - } else + } else { qeth_bridgeport_an_set(card, 0); + } + mutex_unlock(&card->sbp_lock); } /* VNIC CHARS support */ |