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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/qeth_l2_sys.c | |
| 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/qeth_l2_sys.c')
| -rw-r--r-- | drivers/s390/net/qeth_l2_sys.c | 14 |
1 files changed, 13 insertions, 1 deletions
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 */ |