2013-01-09 12:43:16

by Felix Fietkau

[permalink] [raw]
Subject: [PATCH v2 3.8 1/5] ath9k: do not link receive buffers during flush

On AR9300 the rx FIFO needs to be empty during reset to ensure that no
further DMA activity is generated, otherwise it might lead to memory
corruption issues.

Cc: [email protected]
Signed-off-by: Felix Fietkau <[email protected]>
---
drivers/net/wireless/ath/ath9k/recv.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/recv.c b/drivers/net/wireless/ath/ath9k/recv.c
index 3d236ae..db4562d 100644
--- a/drivers/net/wireless/ath/ath9k/recv.c
+++ b/drivers/net/wireless/ath/ath9k/recv.c
@@ -735,6 +735,7 @@ static struct ath_buf *ath_get_next_rx_buf(struct ath_softc *sc,
return NULL;
}

+ list_del(&bf->list);
if (!bf->bf_mpdu)
return bf;

@@ -1245,14 +1246,15 @@ requeue_drop_frag:
sc->rx.frag = NULL;
}
requeue:
+ list_add_tail(&bf->list, &sc->rx.rxbuf);
+ if (!flush)
+ continue;
+
if (edma) {
- list_add_tail(&bf->list, &sc->rx.rxbuf);
ath_rx_edma_buf_link(sc, qtype);
} else {
- list_move_tail(&bf->list, &sc->rx.rxbuf);
ath_rx_buf_link(sc, bf);
- if (!flush)
- ath9k_hw_rxena(ah);
+ ath9k_hw_rxena(ah);
}
} while (1);

--
1.8.0.2



2013-01-09 12:43:15

by Felix Fietkau

[permalink] [raw]
Subject: [PATCH v2 3.8 2/5] ath9k: fix double-free bug on beacon generate failure

When the next beacon is sent, the ath_buf from the previous run is reused.
If getting a new beacon from mac80211 fails, bf->bf_mpdu is not reset, yet
the skb is freed, leading to a double-free on the next beacon tx attempt,
resulting in a system crash.

Cc: [email protected]
Signed-off-by: Felix Fietkau <[email protected]>
---
drivers/net/wireless/ath/ath9k/beacon.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/net/wireless/ath/ath9k/beacon.c b/drivers/net/wireless/ath/ath9k/beacon.c
index 531fffd..4eb269d 100644
--- a/drivers/net/wireless/ath/ath9k/beacon.c
+++ b/drivers/net/wireless/ath/ath9k/beacon.c
@@ -147,6 +147,7 @@ static struct ath_buf *ath9k_beacon_generate(struct ieee80211_hw *hw,
skb->len, DMA_TO_DEVICE);
dev_kfree_skb_any(skb);
bf->bf_buf_addr = 0;
+ bf->bf_mpdu = NULL;
}

skb = ieee80211_beacon_get(hw, vif);
--
1.8.0.2


2013-01-09 12:43:15

by Felix Fietkau

[permalink] [raw]
Subject: [PATCH v2 3.8 5/5] ath9k: fix rx flush handling

Right now the rx flush is not doing anything useful on AR9003+, as it only
works if the buffers in the rx FIFO have not been purged yet, as is done
by ath_stoprecv.

To fix this, always call ath_flushrecv from within ath_stoprecv before
the FIFO is emptied, but still after the hw receive path has been stopped.

This ensures that frames received (and ACKed by the hardware) shortly before
a reset will be seen by the software, which should improve A-MPDU session
stability.

Cc: [email protected]
Signed-off-by: Felix Fietkau <[email protected]>
---
drivers/net/wireless/ath/ath9k/ath9k.h | 1 -
drivers/net/wireless/ath/ath9k/main.c | 16 +++-------------
drivers/net/wireless/ath/ath9k/recv.c | 16 +++++++++-------
3 files changed, 12 insertions(+), 21 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h
index f505b19..49923fb 100644
--- a/drivers/net/wireless/ath/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath/ath9k/ath9k.h
@@ -324,7 +324,6 @@ struct ath_rx {

int ath_startrecv(struct ath_softc *sc);
bool ath_stoprecv(struct ath_softc *sc);
-void ath_flushrecv(struct ath_softc *sc);
u32 ath_calcrxfilter(struct ath_softc *sc);
int ath_rx_init(struct ath_softc *sc, int nbufs);
void ath_rx_cleanup(struct ath_softc *sc);
diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c
index 6d04654..eced021 100644
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -182,7 +182,7 @@ static void ath_restart_work(struct ath_softc *sc)
ath_start_ani(sc);
}

-static bool ath_prepare_reset(struct ath_softc *sc, bool retry_tx, bool flush)
+static bool ath_prepare_reset(struct ath_softc *sc, bool retry_tx)
{
struct ath_hw *ah = sc->sc_ah;
bool ret = true;
@@ -204,14 +204,6 @@ static bool ath_prepare_reset(struct ath_softc *sc, bool retry_tx, bool flush)
if (!ath_drain_all_txq(sc, retry_tx))
ret = false;

- if (!flush) {
- if (ah->caps.hw_caps & ATH9K_HW_CAP_EDMA)
- ath_rx_tasklet(sc, 1, true);
- ath_rx_tasklet(sc, 1, false);
- } else {
- ath_flushrecv(sc);
- }
-
tasklet_enable(&sc->intr_tq);

return ret;
@@ -266,7 +258,6 @@ static int ath_reset_internal(struct ath_softc *sc, struct ath9k_channel *hchan,
struct ath_common *common = ath9k_hw_common(ah);
struct ath9k_hw_cal_data *caldata = NULL;
bool fastcc = true;
- bool flush = false;
int r;

__ath_cancel_work(sc);
@@ -280,11 +271,10 @@ static int ath_reset_internal(struct ath_softc *sc, struct ath9k_channel *hchan,

if (!hchan) {
fastcc = false;
- flush = true;
hchan = ah->curchan;
}

- if (!ath_prepare_reset(sc, retry_tx, flush))
+ if (!ath_prepare_reset(sc, retry_tx))
fastcc = false;

ath_dbg(common, CONFIG, "Reset to %u MHz, HT40: %d fastcc: %d\n",
@@ -808,7 +798,7 @@ static void ath9k_stop(struct ieee80211_hw *hw)
ath9k_hw_cfg_gpio_input(ah, ah->led_pin);
}

- ath_prepare_reset(sc, false, true);
+ ath_prepare_reset(sc, false);

if (sc->rx.frag) {
dev_kfree_skb_any(sc->rx.frag);
diff --git a/drivers/net/wireless/ath/ath9k/recv.c b/drivers/net/wireless/ath/ath9k/recv.c
index b782974..17325a8 100644
--- a/drivers/net/wireless/ath/ath9k/recv.c
+++ b/drivers/net/wireless/ath/ath9k/recv.c
@@ -463,6 +463,13 @@ start_recv:
return 0;
}

+static void ath_flushrecv(struct ath_softc *sc)
+{
+ if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA)
+ ath_rx_tasklet(sc, 1, true);
+ ath_rx_tasklet(sc, 1, false);
+}
+
bool ath_stoprecv(struct ath_softc *sc)
{
struct ath_hw *ah = sc->sc_ah;
@@ -473,6 +480,8 @@ bool ath_stoprecv(struct ath_softc *sc)
ath9k_hw_setrxfilter(ah, 0);
stopped = ath9k_hw_stopdmarecv(ah, &reset);

+ ath_flushrecv(sc);
+
if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA)
ath_edma_stop_recv(sc);
else
@@ -489,13 +498,6 @@ bool ath_stoprecv(struct ath_softc *sc)
return stopped && !reset;
}

-void ath_flushrecv(struct ath_softc *sc)
-{
- if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA)
- ath_rx_tasklet(sc, 1, true);
- ath_rx_tasklet(sc, 1, false);
-}
-
static bool ath_beacon_dtim_pending_cab(struct sk_buff *skb)
{
/* Check whether the Beacon frame has DTIM indicating buffered bc/mc */
--
1.8.0.2


2013-01-09 12:43:16

by Felix Fietkau

[permalink] [raw]
Subject: [PATCH v2 3.8 3/5] ath9k: remove the WARN_ON that triggers if generating a beacon fails

During teardown, mac80211 will not return a new beacon. This is normal and
handled properly in the driver, so there's no need to spam the user with a kernel
warning here.

Cc: [email protected]
Signed-off-by: Felix Fietkau <[email protected]>
---
drivers/net/wireless/ath/ath9k/beacon.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/drivers/net/wireless/ath/ath9k/beacon.c b/drivers/net/wireless/ath/ath9k/beacon.c
index 4eb269d..2ca355e 100644
--- a/drivers/net/wireless/ath/ath9k/beacon.c
+++ b/drivers/net/wireless/ath/ath9k/beacon.c
@@ -360,7 +360,6 @@ void ath9k_beacon_tasklet(unsigned long data)
return;

bf = ath9k_beacon_generate(sc->hw, vif);
- WARN_ON(!bf);

if (sc->beacon.bmisscnt != 0) {
ath_dbg(common, BSTUCK, "resume beacon xmit after %u misses\n",
--
1.8.0.2


2013-01-09 12:43:16

by Felix Fietkau

[permalink] [raw]
Subject: [PATCH v2 3.8 4/5] ath9k: add a better fix for the rx tasklet vs rx flush race

Ensure that the rx tasklet is no longer running when entering the reset path.
Also remove the distinction between flush and no-flush frame processing.
If a frame has been received and ACKed by the hardware, the stack needs to see
it, so that the BA receive window does not go out of sync.

Cc: [email protected]
Signed-off-by: Felix Fietkau <[email protected]>
---
drivers/net/wireless/ath/ath9k/ath9k.h | 1 -
drivers/net/wireless/ath/ath9k/debug.c | 1 -
drivers/net/wireless/ath/ath9k/debug.h | 2 --
drivers/net/wireless/ath/ath9k/main.c | 4 ++++
drivers/net/wireless/ath/ath9k/recv.c | 15 ---------------
5 files changed, 4 insertions(+), 19 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h
index 7250107..f505b19 100644
--- a/drivers/net/wireless/ath/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath/ath9k/ath9k.h
@@ -641,7 +641,6 @@ void ath_ant_comb_update(struct ath_softc *sc);
enum sc_op_flags {
SC_OP_INVALID,
SC_OP_BEACONS,
- SC_OP_RXFLUSH,
SC_OP_ANI_RUN,
SC_OP_PRIM_STA_VIF,
SC_OP_HW_RESET,
diff --git a/drivers/net/wireless/ath/ath9k/debug.c b/drivers/net/wireless/ath/ath9k/debug.c
index 13ff9ed..e585fc8 100644
--- a/drivers/net/wireless/ath/ath9k/debug.c
+++ b/drivers/net/wireless/ath/ath9k/debug.c
@@ -861,7 +861,6 @@ static ssize_t read_file_recv(struct file *file, char __user *user_buf,
RXS_ERR("RX-LENGTH-ERR", rx_len_err);
RXS_ERR("RX-OOM-ERR", rx_oom_err);
RXS_ERR("RX-RATE-ERR", rx_rate_err);
- RXS_ERR("RX-DROP-RXFLUSH", rx_drop_rxflush);
RXS_ERR("RX-TOO-MANY-FRAGS", rx_too_many_frags_err);

PHY_ERR("UNDERRUN ERR", ATH9K_PHYERR_UNDERRUN);
diff --git a/drivers/net/wireless/ath/ath9k/debug.h b/drivers/net/wireless/ath/ath9k/debug.h
index 375c3b4..6df2ab6 100644
--- a/drivers/net/wireless/ath/ath9k/debug.h
+++ b/drivers/net/wireless/ath/ath9k/debug.h
@@ -216,7 +216,6 @@ struct ath_tx_stats {
* @rx_oom_err: No. of frames dropped due to OOM issues.
* @rx_rate_err: No. of frames dropped due to rate errors.
* @rx_too_many_frags_err: Frames dropped due to too-many-frags received.
- * @rx_drop_rxflush: No. of frames dropped due to RX-FLUSH.
* @rx_beacons: No. of beacons received.
* @rx_frags: No. of rx-fragements received.
*/
@@ -235,7 +234,6 @@ struct ath_rx_stats {
u32 rx_oom_err;
u32 rx_rate_err;
u32 rx_too_many_frags_err;
- u32 rx_drop_rxflush;
u32 rx_beacons;
u32 rx_frags;
};
diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c
index e1fa705..6d04654 100644
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -196,6 +196,8 @@ static bool ath_prepare_reset(struct ath_softc *sc, bool retry_tx, bool flush)
ath9k_debug_samp_bb_mac(sc);
ath9k_hw_disable_interrupts(ah);

+ tasklet_disable(&sc->intr_tq);
+
if (!ath_stoprecv(sc))
ret = false;

@@ -210,6 +212,8 @@ static bool ath_prepare_reset(struct ath_softc *sc, bool retry_tx, bool flush)
ath_flushrecv(sc);
}

+ tasklet_enable(&sc->intr_tq);
+
return ret;
}

diff --git a/drivers/net/wireless/ath/ath9k/recv.c b/drivers/net/wireless/ath/ath9k/recv.c
index db4562d..b782974 100644
--- a/drivers/net/wireless/ath/ath9k/recv.c
+++ b/drivers/net/wireless/ath/ath9k/recv.c
@@ -280,7 +280,6 @@ int ath_rx_init(struct ath_softc *sc, int nbufs)

spin_lock_init(&sc->sc_pcu_lock);
spin_lock_init(&sc->rx.rxbuflock);
- clear_bit(SC_OP_RXFLUSH, &sc->sc_flags);

common->rx_bufsize = IEEE80211_MAX_MPDU_LEN / 2 +
sc->sc_ah->caps.rx_status_len;
@@ -492,11 +491,9 @@ bool ath_stoprecv(struct ath_softc *sc)

void ath_flushrecv(struct ath_softc *sc)
{
- set_bit(SC_OP_RXFLUSH, &sc->sc_flags);
if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA)
ath_rx_tasklet(sc, 1, true);
ath_rx_tasklet(sc, 1, false);
- clear_bit(SC_OP_RXFLUSH, &sc->sc_flags);
}

static bool ath_beacon_dtim_pending_cab(struct sk_buff *skb)
@@ -1058,9 +1055,6 @@ int ath_rx_tasklet(struct ath_softc *sc, int flush, bool hp)

do {
bool decrypt_error = false;
- /* If handling rx interrupt and flush is in progress => exit */
- if (test_bit(SC_OP_RXFLUSH, &sc->sc_flags) && (flush == 0))
- break;

memset(&rs, 0, sizeof(rs));
if (edma)
@@ -1103,15 +1097,6 @@ int ath_rx_tasklet(struct ath_softc *sc, int flush, bool hp)

ath_debug_stat_rx(sc, &rs);

- /*
- * If we're asked to flush receive queue, directly
- * chain it back at the queue without processing it.
- */
- if (test_bit(SC_OP_RXFLUSH, &sc->sc_flags)) {
- RX_STAT_INC(rx_drop_rxflush);
- goto requeue_drop_frag;
- }
-
memset(rxs, 0, sizeof(struct ieee80211_rx_status));

rxs->mactime = (tsf & ~0xffffffffULL) | rs.rs_tstamp;
--
1.8.0.2