[PATCH] wireless: iwlwifi: Fix a double free in iwl_txq_dyn_alloc_dma

From: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
To: luciano.coelho@intel.com, kvalo@codeaurora.org,
	davem@davemloft.net, kuba@kernel.org,
	mordechay.goodstein@intel.com, johannes.berg@intel.com,
	emmanuel.grumbach@intel.com
Cc: linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	Lv Yunlong <lyl2019@mail.ustc.edu.cn>
Subject: [PATCH] wireless: iwlwifi: Fix a double free in iwl_txq_dyn_alloc_dma
Date: Fri,  2 Apr 2021 22:47:55 -0700	[thread overview]
Message-ID: <20210403054755.4781-1-lyl2019@mail.ustc.edu.cn> (raw)

In iwl_txq_dyn_alloc_dma, txq->tfds is freed at first time by:
iwl_txq_alloc()->goto err_free_tfds->dma_free_coherent(). But
it forgot to set txq->tfds to NULL.

Then the txq->tfds is freed again in iwl_txq_dyn_alloc_dma by:
goto error->iwl_txq_gen2_free_memory()->dma_free_coherent().

My patch sets txq->tfds to NULL after the first free to avoid the
double free.

Fixes: 0cd1ad2d7fd41 ("iwlwifi: move all bus-independent TX functions to common code")
Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
---
 drivers/net/wireless/intel/iwlwifi/queue/tx.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/wireless/intel/iwlwifi/queue/tx.c b/drivers/net/wireless/intel/iwlwifi/queue/tx.c
index 833f43d1ca7a..99c8e473031a 100644
--- a/drivers/net/wireless/intel/iwlwifi/queue/tx.c
+++ b/drivers/net/wireless/intel/iwlwifi/queue/tx.c
@@ -1101,6 +1101,7 @@ int iwl_txq_alloc(struct iwl_trans *trans, struct iwl_txq *txq, int slots_num,
 	return 0;
 err_free_tfds:
 	dma_free_coherent(trans->dev, tfd_sz, txq->tfds, txq->dma_addr);
+	txq->tfds = NULL;
 error:
 	if (txq->entries && cmd_queue)
 		for (i = 0; i < slots_num; i++)
-- 
2.25.1


