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From:   Manikanta Pubbisetty <quic_mpubbise@quicinc.com>
To:     <ath11k@lists.infradead.org>
CC:     <linux-wireless@vger.kernel.org>,
        Manikanta Pubbisetty <quic_mpubbise@quicinc.com>
Subject: [PATCH v3 1/3] ath11k: Fix double free issue during SRNG deinit
Date:   Mon, 21 Nov 2022 16:33:57 +0530
Message-ID: <20221121110359.4652-2-quic_mpubbise@quicinc.com>
In-Reply-To: <20221121110359.4652-1-quic_mpubbise@quicinc.com>
References: <20221121110359.4652-1-quic_mpubbise@quicinc.com>
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Currently struct ath11k_hal::srng_config pointer is not assigned
to NULL after freeing the memory in ath11k_hal_srng_deinit().
This could lead to double free issue in a scenario where
ath11k_hal_srng_deinit() is invoked back to back.

In the current code, although the chances are very low, the above
said scenario could happen when hardware recovery has failed and
then there is another FW assert where ath11k_hal_srng_deinit() is
invoked once again as part of recovery. Addressing this issue is
important when low power mode support is enabled in the driver
(will be added by a future patch) where this scenario is likely.

Fix this by assigning the struct ath11k_hal::srng_config pointer
to NULL after freeing the memory.

Tested-on: WCN6750 hw1.0 AHB WLAN.MSL.1.0.1-00887-QCAMSLSWPLZ-1
Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.16

Signed-off-by: Manikanta Pubbisetty <quic_mpubbise@quicinc.com>
---
 drivers/net/wireless/ath/ath11k/hal.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/wireless/ath/ath11k/hal.c b/drivers/net/wireless/ath/ath11k/hal.c
index 2fd224480d45..e92c741526f8 100644
--- a/drivers/net/wireless/ath/ath11k/hal.c
+++ b/drivers/net/wireless/ath/ath11k/hal.c
@@ -1319,6 +1319,7 @@ void ath11k_hal_srng_deinit(struct ath11k_base *ab)
 	ath11k_hal_free_cont_rdp(ab);
 	ath11k_hal_free_cont_wrp(ab);
 	kfree(hal->srng_config);
+	hal->srng_config = NULL;
 }
 EXPORT_SYMBOL(ath11k_hal_srng_deinit);
 
-- 
2.38.0