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From: Arnd Bergmann <arnd@kernel.org>
To: Kalle Valo <kvalo@codeaurora.org>,
	Alagu Sankar <alagusankar@silex-india.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Brian Norris <briannorris@chromium.org>,
	Wen Gong <wgong@codeaurora.org>,
	Tamizh Chelvam <tamizhr@codeaurora.org>,
	Carl Huang <cjhuang@codeaurora.org>,
	Miaoqing Pan <miaoqing@codeaurora.org>,
	Ben Greear <greearb@candelatech.com>,
	Erik Stromdahl <erik.stromdahl@gmail.com>,
	Fabio Estevam <festevam@denx.de>,
	ath10k@lists.infradead.org, linux-wireless@vger.kernel.org,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] ath10k: fix invalid dma_addr_t token assignment
Date: Thu, 14 Oct 2021 09:51:15 +0200	[thread overview]
Message-ID: <20211014075153.3655910-1-arnd@kernel.org> (raw)

From: Arnd Bergmann <arnd@arndb.de>

Using a kernel pointer in place of a dma_addr_t token can
lead to undefined behavior if that makes it into cache
management functions. The compiler caught one such attempt
in a cast:

drivers/net/wireless/ath/ath10k/mac.c: In function 'ath10k_add_interface':
drivers/net/wireless/ath/ath10k/mac.c:5586:47: error: cast from pointer to integer of different size [-Werror=pointer-to-int-cast]
 5586 |                         arvif->beacon_paddr = (dma_addr_t)arvif->beacon_buf;
      |                                               ^

Looking through how this gets used down the way, I'm fairly
sure that beacon_paddr is never accessed again for ATH10K_DEV_TYPE_HL
devices, and if it was accessed, that would be a bug.

Change the assignment to use a known-invalid address token
instead, which avoids the warning and makes it easier to catch
bugs if it does end up getting used.

Fixes: e263bdab9c0e ("ath10k: high latency fixes for beacon buffer")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/net/wireless/ath/ath10k/mac.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c
index 7ca68c81d9b6..c0e78eaa65f8 100644
--- a/drivers/net/wireless/ath/ath10k/mac.c
+++ b/drivers/net/wireless/ath/ath10k/mac.c
@@ -5583,7 +5583,7 @@ static int ath10k_add_interface(struct ieee80211_hw *hw,
 		if (ar->bus_param.dev_type == ATH10K_DEV_TYPE_HL) {
 			arvif->beacon_buf = kmalloc(IEEE80211_MAX_FRAME_LEN,
 						    GFP_KERNEL);
-			arvif->beacon_paddr = (dma_addr_t)arvif->beacon_buf;
+			arvif->beacon_paddr = DMA_MAPPING_ERROR;
 		} else {
 			arvif->beacon_buf =
 				dma_alloc_coherent(ar->dev,
-- 
2.29.2


             reply	other threads:[~2021-10-14  7:52 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-14  7:51 Arnd Bergmann [this message]
2021-10-18 13:10 ` [PATCH] ath10k: fix invalid dma_addr_t token assignment Kalle Valo
2021-10-25 12:16 ` Fabio Estevam
2021-10-25 13:04 ` Kalle Valo

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