Subject: Re: [PATCH v2] iwl4965: Fix a null pointer dereference in il_tx_queue_free and il_cmd_queue_free

From: Stanislaw Gruszka <[email-masked]>
Date: Mon, 11 Jan 2016 15:04:31 +0100

On Mon, Jan 11, 2016 at 09:42:54PM +0800, Jia-Ju Bai wrote:
> If "txq->cmd = kzalloc(...)" in il_tx_queue_init fails,
> "kfree(txq->cmd[i])" in il_tx_queue_free and il_cmd_queue_free
> in iwl4965_hw_txq_ctx_free will causes a null pointer dereference,
> because txq->cmd is NULL at that time.
> 
> This patch fixes this problem by adding a if-check before kfree.
> To avoid double free in il_tx_queue_free and il_cmd_queue_free
> caused by the fixing, txq->meta and txq->cmd in error handling code
> of il_tx_queue_init are assigned null values. 
> Otherwise, a double free will occur.
> 
> This patch has been tested in real device, and it actually fixes the bug.
> Thanks Stanislaw for his suggestion.
> 
> Signed-off-by: Jia-Ju Bai <baijiaju1990-9Onoh4P/[email-masked]>

Acked-by: Stanislaw Gruszka <[email-masked]>

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