From 1af8dc9ca726cf53767f9c0661171396f95c146a Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Toke=20H=C3=B8iland-J=C3=B8rgensen?= Date: Tue, 8 Sep 2026 19:05:18 +0200 Subject: [PATCH] wifi: ath9k: Clean up device initialisation guards MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The ath9k driver has a couple of guards against the RX path running until device initialisation has completed. However, they are problematic for several reasons: - They use smp_wmb() paired with a data_race() annotation, instead of the idiomatic smp_store_release()/smp_load_acquire() pair. - The guard in ath9k_wmi_event_tasklet() is weirdly late in the function. - There are two of them when there's really no reason the rx init gets to run before the whole initialisation is complete. Consolidate the guards on the single ath9k_htc_priv->initialized variable and use smp_store_release()/smp_load_acquire() to access it. Move the store into ath9k_init_device() to make sure it's set in all paths in the driver. Fixes: 24355fcb0d4c ("wifi: ath9k: delay all of ath9k_wmi_event_tasklet() until init is complete") Fixes: b0ec7e55fce6 ("ath9k_htc: fix NULL pointer dereference at ath9k_htc_rxep()") Signed-off-by: Toke Høiland-Jørgensen Link: https://patch.msgid.link/20260908170520.112946-1-toke@redhat.com Signed-off-by: Jeff Johnson --- drivers/net/wireless/ath/ath9k/htc.h | 1 - drivers/net/wireless/ath/ath9k/htc_drv_init.c | 7 +++---- drivers/net/wireless/ath/ath9k/htc_drv_txrx.c | 8 ++------ drivers/net/wireless/ath/ath9k/wmi.c | 12 ++++++------ 4 files changed, 11 insertions(+), 17 deletions(-) diff --git a/drivers/net/wireless/ath/ath9k/htc.h b/drivers/net/wireless/ath/ath9k/htc.h index 6c33e898b300..4d2b75d0212e 100644 --- a/drivers/net/wireless/ath/ath9k/htc.h +++ b/drivers/net/wireless/ath/ath9k/htc.h @@ -281,7 +281,6 @@ struct ath9k_htc_rxbuf { struct ath9k_htc_rx { struct list_head rxbuf; spinlock_t rxbuflock; - bool initialized; }; #define ATH9K_HTC_TX_CLEANUP_INTERVAL 50 /* ms */ diff --git a/drivers/net/wireless/ath/ath9k/htc_drv_init.c b/drivers/net/wireless/ath/ath9k/htc_drv_init.c index 6de78ae85726..911eaa4f776a 100644 --- a/drivers/net/wireless/ath/ath9k/htc_drv_init.c +++ b/drivers/net/wireless/ath/ath9k/htc_drv_init.c @@ -910,6 +910,9 @@ static int ath9k_init_device(struct ath9k_htc_priv *priv, ath9k_init_leds(priv); ath9k_start_rfkill_poll(priv); + /* signal completion to ath9k_htc_rxep() and ath9k_wmi_event_tasklet() */ + smp_store_release(&priv->initialized, true); + return 0; err_world: @@ -966,10 +969,6 @@ int ath9k_htc_probe_device(struct htc_target *htc_handle, struct device *dev, htc_handle->drv_priv = priv; - /* Allow ath9k_wmi_event_tasklet() to operate. */ - smp_wmb(); - priv->initialized = true; - return 0; err_init: diff --git a/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c b/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c index bed7ea2425a0..95f48c7dca15 100644 --- a/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c +++ b/drivers/net/wireless/ath/ath9k/htc_drv_txrx.c @@ -1141,8 +1141,8 @@ void ath9k_htc_rxep(void *drv_priv, struct sk_buff *skb, struct ath9k_htc_rxbuf *rxbuf = NULL, *tmp_buf = NULL; unsigned long flags; - /* Check if ath9k_rx_init() completed. */ - if (!data_race(priv->rx.initialized)) + /* Check if ath9k_init_device() completed. */ + if (!smp_load_acquire(&priv->initialized)) goto err; spin_lock_irqsave(&priv->rx.rxbuflock, flags); @@ -1200,10 +1200,6 @@ int ath9k_rx_init(struct ath9k_htc_priv *priv) list_add_tail(&rxbuf->list, &priv->rx.rxbuf); } - /* Allow ath9k_htc_rxep() to operate. */ - smp_wmb(); - priv->rx.initialized = true; - return 0; err: diff --git a/drivers/net/wireless/ath/ath9k/wmi.c b/drivers/net/wireless/ath/ath9k/wmi.c index 284e8c13b043..44e91815a159 100644 --- a/drivers/net/wireless/ath/ath9k/wmi.c +++ b/drivers/net/wireless/ath/ath9k/wmi.c @@ -146,6 +146,12 @@ void ath9k_wmi_event_tasklet(struct tasklet_struct *t) unsigned long flags; u16 cmd_id; + /* Check if ath9k_init_device() completed. */ + if (!smp_load_acquire(&priv->initialized)) { + tasklet_schedule(t); + return; + } + do { spin_lock_irqsave(&wmi->wmi_lock, flags); skb = __skb_dequeue(&wmi->wmi_event_queue); @@ -155,12 +161,6 @@ void ath9k_wmi_event_tasklet(struct tasklet_struct *t) } spin_unlock_irqrestore(&wmi->wmi_lock, flags); - /* Check if ath9k_htc_probe_device() completed. */ - if (!data_race(priv->initialized)) { - kfree_skb(skb); - continue; - } - hdr = (struct wmi_cmd_hdr *) skb->data; cmd_id = be16_to_cpu(hdr->command_id); wmi_event = skb_pull(skb, sizeof(struct wmi_cmd_hdr));