[PATCH net-next 08/11] ath9k: work around false-positive gcc warning

[Arnd Bergmann]

From: Arnd Bergmann <a...@arndb.de>

gcc-10 shows a false-positive warning with CONFIG_KASAN:

drivers/net/wireless/ath/ath9k/dynack.c: In function 'ath_dynack_sample_tx_ts':
include/linux/etherdevice.h:290:14: warning: writing 4 bytes into a region of 
size 0 [-Wstringop-overflow=]
  290 |  *(u32 *)dst = *(const u32 *)src;
      |  ~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~

Until gcc is fixed, work around this by using memcpy() in place
of ether_addr_copy(). Hopefully gcc-11 will not have this problem.

Link: https://godbolt.org/z/sab1MK
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97490
Signed-off-by: Arnd Bergmann <a...@arndb.de>
---
 drivers/net/wireless/ath/ath9k/dynack.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/wireless/ath/ath9k/dynack.c 
b/drivers/net/wireless/ath/ath9k/dynack.c
index fbeb4a739d32..e4eb96b26ca4 100644
--- a/drivers/net/wireless/ath/ath9k/dynack.c
+++ b/drivers/net/wireless/ath/ath9k/dynack.c
@@ -247,8 +247,14 @@ void ath_dynack_sample_tx_ts(struct ath_hw *ah, struct 
sk_buff *skb,
        ridx = ts->ts_rateindex;
 
        da->st_rbf.ts[da->st_rbf.t_rb].tstamp = ts->ts_tstamp;
+#if defined(CONFIG_KASAN) && (CONFIG_GCC_VERSION >= 100000) && 
(CONFIG_GCC_VERSION < 110000)
+       /* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97490 */
+       memcpy(da->st_rbf.addr[da->st_rbf.t_rb].h_dest, hdr->addr1, ETH_ALEN);
+       memcpy(da->st_rbf.addr[da->st_rbf.t_rb].h_src, hdr->addr2, ETH_ALEN);
+#else
        ether_addr_copy(da->st_rbf.addr[da->st_rbf.t_rb].h_dest, hdr->addr1);
        ether_addr_copy(da->st_rbf.addr[da->st_rbf.t_rb].h_src, hdr->addr2);
+#endif
 
        if (!(info->status.rates[ridx].flags & IEEE80211_TX_RC_MCS)) {
                const struct ieee80211_rate *rate;
-- 
2.27.0