[PATCH v2 2/2] ath10k: fix beacon deadlock
Michal Kazior
michal.kazior at tieto.com
Wed Jan 28 02:22:05 PST 2015
This should fix a very rare occurrence of the following deadlock:
[<ffffffffa018265e>] ath10k_wmi_tx_beacons_nowait+0x1e/0x50 [ath10k_core]
[<ffffffffa01829b6>] ath10k_wmi_op_ep_tx_credits+0x16/0x40 [ath10k_core]
[<ffffffffa017d685>] ath10k_htc_send+0x285/0x3d0 [ath10k_core]
[<ffffffffa0184b81>] ath10k_wmi_cmd_send_nowait+0x81/0x110 [ath10k_core]
[<ffffffffa0184c61>] ath10k_wmi_tx_beacon_nowait.part.33+0x51/0x90 [ath10k_core]
[<ffffffffa0184cd0>] ath10k_wmi_tx_beacons_iter+0x30/0x40 [ath10k_core]
[<ffffffff81882246>] __iterate_active_interfaces+0xa6/0x100
[<ffffffffa0184ca0>] ? ath10k_wmi_tx_beacon_nowait.part.33+0x90/0x90 [ath10k_core]
[<ffffffff818822ae>] ieee80211_iterate_active_interfaces_atomic+0xe/0x10
[<ffffffffa0182676>] ath10k_wmi_tx_beacons_nowait+0x36/0x50 [ath10k_core]
[<ffffffffa01829b6>] ath10k_wmi_op_ep_tx_credits+0x16/0x40 [ath10k_core]
[<ffffffffa017d140>] ath10k_htc_rx+0x280/0x410 [ath10k_core]
[<ffffffffa01bcbf0>] ? ath10k_ce_completed_recv_next+0x60/0x80 [ath10k_pci]
[<ffffffffa01bc6ab>] ath10k_pci_ce_recv_data+0x11b/0x1d0 [ath10k_pci]
[<ffffffffa01bcf44>] ath10k_ce_per_engine_service+0x64/0xc0 [ath10k_pci]
[<ffffffffa01bcfc2>] ath10k_ce_per_engine_service_any+0x22/0x50 [ath10k_pci]
[<ffffffffa01bc4d0>] ath10k_pci_tasklet+0x30/0x90 [ath10k_pci]
[<ffffffff81055a55>] tasklet_action+0xc5/0x100
To prevent this make sure to release ar->data_lock
while calling to ath10k_wmi_beacon_send_ref_nowait().
Signed-off-by: Michal Kazior <michal.kazior at tieto.com>
---
drivers/net/wireless/ath/ath10k/core.h | 8 +++-
drivers/net/wireless/ath/ath10k/mac.c | 6 ++-
drivers/net/wireless/ath/ath10k/wmi.c | 68 +++++++++++++++++++++++-----------
3 files changed, 58 insertions(+), 24 deletions(-)
diff --git a/drivers/net/wireless/ath/ath10k/core.h b/drivers/net/wireless/ath/ath10k/core.h
index 2d9f871..67e6b46 100644
--- a/drivers/net/wireless/ath/ath10k/core.h
+++ b/drivers/net/wireless/ath/ath10k/core.h
@@ -262,6 +262,12 @@ struct ath10k_sta {
#define ATH10K_VDEV_SETUP_TIMEOUT_HZ (5*HZ)
+enum ath10k_beacon_state {
+ ATH10K_BEACON_SCHEDULED = 0,
+ ATH10K_BEACON_SENDING,
+ ATH10K_BEACON_SENT,
+};
+
struct ath10k_vif {
struct list_head list;
@@ -272,7 +278,7 @@ struct ath10k_vif {
u32 dtim_period;
struct sk_buff *beacon;
/* protected by data_lock */
- bool beacon_sent;
+ enum ath10k_beacon_state beacon_state;
void *beacon_buf;
dma_addr_t beacon_paddr;
diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c
index 4ff6dd0..2a51f0e 100644
--- a/drivers/net/wireless/ath/ath10k/mac.c
+++ b/drivers/net/wireless/ath/ath10k/mac.c
@@ -521,10 +521,14 @@ void ath10k_mac_vif_beacon_free(struct ath10k_vif *arvif)
dma_unmap_single(ar->dev, ATH10K_SKB_CB(arvif->beacon)->paddr,
arvif->beacon->len, DMA_TO_DEVICE);
+ if (WARN_ON(arvif->beacon_state != ATH10K_BEACON_SCHEDULED &&
+ arvif->beacon_state != ATH10K_BEACON_SENT))
+ return;
+
dev_kfree_skb_any(arvif->beacon);
arvif->beacon = NULL;
- arvif->beacon_sent = false;
+ arvif->beacon_state = ATH10K_BEACON_SCHEDULED;
}
static void ath10k_mac_vif_beacon_cleanup(struct ath10k_vif *arvif)
diff --git a/drivers/net/wireless/ath/ath10k/wmi.c b/drivers/net/wireless/ath/ath10k/wmi.c
index 459b203..a398193 100644
--- a/drivers/net/wireless/ath/ath10k/wmi.c
+++ b/drivers/net/wireless/ath/ath10k/wmi.c
@@ -956,30 +956,45 @@ err_pull:
static void ath10k_wmi_tx_beacon_nowait(struct ath10k_vif *arvif)
{
- struct sk_buff *bcn;
+ struct ath10k *ar = arvif->ar;
struct ath10k_skb_cb *cb;
+ struct sk_buff *bcn;
int ret;
- lockdep_assert_held(&arvif->ar->data_lock);
+ spin_lock_bh(&ar->data_lock);
- if (arvif->beacon == NULL)
- return;
+ bcn = arvif->beacon;
- if (arvif->beacon_sent)
- return;
+ if (!bcn)
+ goto unlock;
- bcn = arvif->beacon;
cb = ATH10K_SKB_CB(bcn);
- ret = ath10k_wmi_beacon_send_ref_nowait(arvif->ar, arvif->vdev_id,
- bcn->data, bcn->len, cb->paddr,
- cb->bcn.dtim_zero,
- cb->bcn.deliver_cab);
- if (ret)
- return;
- /* We need to retain the arvif->beacon reference for DMA unmapping and
- * freeing the skbuff later. */
- arvif->beacon_sent = true;
+ switch (arvif->beacon_state) {
+ case ATH10K_BEACON_SENDING:
+ case ATH10K_BEACON_SENT:
+ break;
+ case ATH10K_BEACON_SCHEDULED:
+ arvif->beacon_state = ATH10K_BEACON_SENDING;
+ spin_unlock_bh(&ar->data_lock);
+
+ ret = ath10k_wmi_beacon_send_ref_nowait(arvif->ar,
+ arvif->vdev_id,
+ bcn->data, bcn->len,
+ cb->paddr,
+ cb->bcn.dtim_zero,
+ cb->bcn.deliver_cab);
+
+ spin_lock_bh(&ar->data_lock);
+
+ if (ret == 0)
+ arvif->beacon_state = ATH10K_BEACON_SENT;
+ else
+ arvif->beacon_state = ATH10K_BEACON_SCHEDULED;
+ }
+
+unlock:
+ spin_unlock_bh(&ar->data_lock);
}
static void ath10k_wmi_tx_beacons_iter(void *data, u8 *mac,
@@ -992,12 +1007,10 @@ static void ath10k_wmi_tx_beacons_iter(void *data, u8 *mac,
static void ath10k_wmi_tx_beacons_nowait(struct ath10k *ar)
{
- spin_lock_bh(&ar->data_lock);
ieee80211_iterate_active_interfaces_atomic(ar->hw,
IEEE80211_IFACE_ITER_NORMAL,
ath10k_wmi_tx_beacons_iter,
NULL);
- spin_unlock_bh(&ar->data_lock);
}
static void ath10k_wmi_op_ep_tx_credits(struct ath10k *ar)
@@ -2459,9 +2472,19 @@ void ath10k_wmi_event_host_swba(struct ath10k *ar, struct sk_buff *skb)
spin_lock_bh(&ar->data_lock);
if (arvif->beacon) {
- if (!arvif->beacon_sent)
- ath10k_warn(ar, "SWBA overrun on vdev %d\n",
+ switch (arvif->beacon_state) {
+ case ATH10K_BEACON_SENT:
+ break;
+ case ATH10K_BEACON_SCHEDULED:
+ ath10k_warn(ar, "SWBA overrun on vdev %d, skipped old beacon\n",
+ arvif->vdev_id);
+ break;
+ case ATH10K_BEACON_SENDING:
+ ath10k_warn(ar, "SWBA overrun on vdev %d, skipped new beacon\n",
arvif->vdev_id);
+ dev_kfree_skb(bcn);
+ goto skip;
+ }
ath10k_mac_vif_beacon_free(arvif);
}
@@ -2489,15 +2512,16 @@ void ath10k_wmi_event_host_swba(struct ath10k *ar, struct sk_buff *skb)
}
arvif->beacon = bcn;
- arvif->beacon_sent = false;
+ arvif->beacon_state = ATH10K_BEACON_SCHEDULED;
trace_ath10k_tx_hdr(ar, bcn->data, bcn->len);
trace_ath10k_tx_payload(ar, bcn->data, bcn->len);
- ath10k_wmi_tx_beacon_nowait(arvif);
skip:
spin_unlock_bh(&ar->data_lock);
}
+
+ ath10k_wmi_tx_beacons_nowait(ar);
}
void ath10k_wmi_event_tbttoffset_update(struct ath10k *ar, struct sk_buff *skb)
--
1.8.5.3
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