It was observed that the codepath for the ATH11K_SKB_HW_80211_ENCAP was used even when the IEEE80211_TX_CTRL_HW_80211_ENCAP was not enabled for a an skbuff. This became even more prominent when the QCAs wlan-open patchset for ath11k [1] was applied and a sane looking fix just caused crashes when injecting frames via a monitor interface (for example with ratechecker): [ 86.963152] Unable to handle kernel NULL pointer dereference at virtual address 00000338 [ 86.963192] pgd = ffffffc0008f0000 [ 86.971034] [00000338] *pgd=0000000051706003, *pud=0000000051706003, *pmd=0000000051707003, *pte=00e800000b000707 [ 86.984292] Internal error: Oops: 96000006 [#1] PREEMPT SMP [...] [ 87.713339] [<ffffffbffc802480>] ieee80211_tx_status_8023+0xf8/0x220 [mac80211] [ 87.715654] [<ffffffbffc98bad4>] ath11k_dp_tx_completion_handler+0x42c/0xa10 [ath11k] [ 87.722924] [<ffffffbffc989190>] ath11k_dp_service_srng+0x70/0x3c8 [ath11k] [ 87.730831] [<ffffffbffca03460>] 0xffffffbffca03460 [ 87.737599] [<ffffffc00046ef58>] net_rx_action+0xf8/0x288 [ 87.742462] [<ffffffc000097554>] __do_softirq+0xfc/0x220 [ 87.748014] [<ffffffc000097900>] irq_exit+0x98/0xe8 [ 87.753396] [<ffffffc0000cf188>] __handle_domain_irq+0x90/0xb8 [ 87.757999] [<ffffffc000081ca4>] gic_handle_irq+0x6c/0xc8 [ 87.763899] Exception stack(0xffffffc00081bdc0 to 0xffffffc00081bef0) Problem is that the state of ath11k_skb_cb->flags must be considered unknown and could contain anything when it is not manually initialized. So it could also contain ATH11K_SKB_HW_80211_ENCAP. And this can result in the code to assume that the ath11k_skb_cb->vif is set - even when this is not always the case for non ATH11K_SKB_HW_80211_ENCAP transmissions. Tested-on: IPQ8074 hw2.0 WLAN.HK.2.4.0.1.r1-00026-QCAHKSWPL_SILICONZ-2 [1] https://source.codeaurora.org/quic/qsdk/oss/system/feeds/wlan-open/tree/mac80211/patches?h=NHSS.QSDK.11.4.r3 (162 patches at the moment which are often not upstreamed but essential to get ath11k working) Fixes: e7f33e0c52c0 ("ath11k: add tx hw 802.11 encapsulation offloading support") Signed-off-by: Sven Eckelmann <sven@xxxxxxxxxxxxx> --- v2: - nothing changed drivers/net/wireless/ath/ath11k/mac.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/net/wireless/ath/ath11k/mac.c b/drivers/net/wireless/ath/ath11k/mac.c index 05ed6ec99b55..591c4c57b61e 100644 --- a/drivers/net/wireless/ath/ath11k/mac.c +++ b/drivers/net/wireless/ath/ath11k/mac.c @@ -4057,6 +4057,7 @@ static void ath11k_mac_op_tx(struct ieee80211_hw *hw, bool is_prb_rsp; int ret; + memset(skb_cb, 0, sizeof(*skb_cb)); skb_cb->vif = vif; if (key) { -- 2.29.2
