From c254f7893bc17065fc24466758602da9ee6aadaa Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@arndb.de>
Date: Wed, 20 Oct 2021 11:59:07 +0300
Subject: [PATCH] ath10k: fix invalid dma_addr_t token assignment
Git-commit: 937e79c67740d1d84736730d679f3cb2552f990e
Patch-mainline: v5.16-rc1
References: stable-5.14.19
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>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/net/wireless/ath/ath10k/mac.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c
index 5ec19d91cf37..1f73fbfee0c0 100644
--- a/drivers/net/wireless/ath/ath10k/mac.c
+++ b/drivers/net/wireless/ath/ath10k/mac.c
@@ -5583,7 +5583,15 @@ 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,
--
2.26.2