ath11k: Avoid NULL ptr access during mgmt tx cleanup

Currently 'ar' reference is not added in skb_cb during
WMI mgmt tx. Though this is generally not used during tx completion
callbacks, on interface removal the remaining idr cleanup callback
uses the ar ptr from skb_cb from mgmt txmgmt_idr. Hence
fill them during tx call for proper usage.

Also free the skb which is missing currently in these
callbacks.

Crash_info:

[19282.489476] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[19282.489515] pgd = 91eb8000
[19282.496702] [00000000] *pgd=00000000
[19282.502524] Internal error: Oops: 5 [#1] PREEMPT SMP ARM
[19282.783728] PC is at ath11k_mac_vif_txmgmt_idr_remove+0x28/0xd8 [ath11k]
[19282.789170] LR is at idr_for_each+0xa0/0xc8

Tested-on: IPQ8074 hw2.0 AHB WLAN.HK.2.5.0.1-00729-QCAHKSWPL_SILICONZ-3 v2
Signed-off-by: Sriram R <quic_srirrama@quicinc.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1637832614-13831-1-git-send-email-quic_srirrama@quicinc.com

diff --git a/drivers/net/wireless/ath/ath11k/mac.c b/drivers/net/wireless/ath/ath11k/mac.c
index 06d20658586a1e6704b19a5125639f2ac78bed7f..0050e2c84888eb5a8d36bbde0c1cfafbf065073c 100644 (file)
--- a/drivers/net/wireless/ath/ath11k/mac.c
+++ b/drivers/net/wireless/ath/ath11k/mac.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: BSD-3-Clause-Clear
 /*
  * Copyright (c) 2018-2019 The Linux Foundation. All rights reserved.
+ * Copyright (c) 2021 Qualcomm Innovation Center, Inc. All rights reserved.
  */
 
 #include <net/mac80211.h>
@@ -5224,23 +5225,32 @@ static int __ath11k_set_antenna(struct ath11k *ar, u32 tx_ant, u32 rx_ant)
        return 0;
 }
 
-int ath11k_mac_tx_mgmt_pending_free(int buf_id, void *skb, void *ctx)
+static void ath11k_mac_tx_mgmt_free(struct ath11k *ar, int buf_id)
 {
-       struct sk_buff *msdu = skb;
+       struct sk_buff *msdu;
        struct ieee80211_tx_info *info;
-       struct ath11k *ar = ctx;
-       struct ath11k_base *ab = ar->ab;
 
        spin_lock_bh(&ar->txmgmt_idr_lock);
-       idr_remove(&ar->txmgmt_idr, buf_id);
+       msdu = idr_remove(&ar->txmgmt_idr, buf_id);
        spin_unlock_bh(&ar->txmgmt_idr_lock);
-       dma_unmap_single(ab->dev, ATH11K_SKB_CB(msdu)->paddr, msdu->len,
+
+       if (!msdu)
+               return;
+
+       dma_unmap_single(ar->ab->dev, ATH11K_SKB_CB(msdu)->paddr, msdu->len,
                         DMA_TO_DEVICE);
 
        info = IEEE80211_SKB_CB(msdu);
        memset(&info->status, 0, sizeof(info->status));
 
        ieee80211_free_txskb(ar->hw, msdu);
+}
+
+int ath11k_mac_tx_mgmt_pending_free(int buf_id, void *skb, void *ctx)
+{
+       struct ath11k *ar = ctx;
+
+       ath11k_mac_tx_mgmt_free(ar, buf_id);
 
        return 0;
 }
@@ -5249,17 +5259,10 @@ static int ath11k_mac_vif_txmgmt_idr_remove(int buf_id, void *skb, void *ctx)
 {
        struct ieee80211_vif *vif = ctx;
        struct ath11k_skb_cb *skb_cb = ATH11K_SKB_CB((struct sk_buff *)skb);
-       struct sk_buff *msdu = skb;
        struct ath11k *ar = skb_cb->ar;
-       struct ath11k_base *ab = ar->ab;
 
-       if (skb_cb->vif == vif) {
-               spin_lock_bh(&ar->txmgmt_idr_lock);
-               idr_remove(&ar->txmgmt_idr, buf_id);
-               spin_unlock_bh(&ar->txmgmt_idr_lock);
-               dma_unmap_single(ab->dev, skb_cb->paddr, msdu->len,
-                                DMA_TO_DEVICE);
-       }
+       if (skb_cb->vif == vif)
+               ath11k_mac_tx_mgmt_free(ar, buf_id);
 
        return 0;
 }
@@ -5274,6 +5277,8 @@ static int ath11k_mac_mgmt_tx_wmi(struct ath11k *ar, struct ath11k_vif *arvif,
        int buf_id;
        int ret;
 
+       ATH11K_SKB_CB(skb)->ar = ar;
+
        spin_lock_bh(&ar->txmgmt_idr_lock);
        buf_id = idr_alloc(&ar->txmgmt_idr, skb, 0,
                           ATH11K_TX_MGMT_NUM_PENDING_MAX, GFP_ATOMIC);