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ath10k: fix invalid dma_addr_t token assignment

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commit 937e79c67740d1d84736730d679f3cb2552f990e upstream.

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>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20211014075153.3655910-1-arnd@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Arnd Bergmann
2021-10-20 11:59:07 +03:00
committed by Greg Kroah-Hartman
parent d41f4d4dd7
commit 188bf40391
1 changed files with 9 additions and 1 deletions
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10
drivers/net/wireless/ath/ath10k/mac.c
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@@ -5473,7 +5473,15 @@ 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;
/* 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. 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.
*/
arvif->beacon_paddr = DMA_MAPPING_ERROR;
} else {
arvif->beacon_buf =
dma_alloc_coherent(ar->dev,