The driver_data area of ieee80211_tx_info is used in ath11k for
ath11k_skb_cb. The first function in the TX patch which rewrites it to
ath11k_skb_cb is already ath11k_mac_op_tx. No one else in the code path
must use it for something else before it reinitializes it. Otherwise the
data has to be considered uninitialized or corrupt.
But the ieee80211_tx_info.control shares exactly the same area as
ieee80211_tx_info.driver_data and ath11k is still using it. This results in
best case in a
ath11k c000000.wifi1: no vif found for mgmt frame, flags 0x0
or (slightly worse) in a kernel oops.
Instead, the interesting data must be moved first into the ath11k_skb_cb
and ieee80211_tx_info.control must then not be used anymore.
Tested-on: IPQ8074 hw2.0 WLAN.HK.2.4.0.1.r1-00026-QCAHKSWPL_SILICONZ-2
Fixes: d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices")
Signed-off-by: Sven Eckelmann <[email protected]>
---
drivers/net/wireless/ath/ath11k/mac.c | 20 +++++++++++---------
1 file changed, 11 insertions(+), 9 deletions(-)
diff --git a/drivers/net/wireless/ath/ath11k/mac.c b/drivers/net/wireless/ath/ath11k/mac.c
index 7f8dd47d2333..0296ba925455 100644
--- a/drivers/net/wireless/ath/ath11k/mac.c
+++ b/drivers/net/wireless/ath/ath11k/mac.c
@@ -3977,21 +3977,20 @@ static void ath11k_mgmt_over_wmi_tx_purge(struct ath11k *ar)
static void ath11k_mgmt_over_wmi_tx_work(struct work_struct *work)
{
struct ath11k *ar = container_of(work, struct ath11k, wmi_mgmt_tx_work);
- struct ieee80211_tx_info *info;
+ struct ath11k_skb_cb *skb_cb;
struct ath11k_vif *arvif;
struct sk_buff *skb;
int ret;
while ((skb = skb_dequeue(&ar->wmi_mgmt_tx_queue)) != NULL) {
- info = IEEE80211_SKB_CB(skb);
- if (!info->control.vif) {
- ath11k_warn(ar->ab, "no vif found for mgmt frame, flags 0x%x\n",
- info->control.flags);
+ skb_cb = ATH11K_SKB_CB(skb);
+ if (!skb_cb->vif) {
+ ath11k_warn(ar->ab, "no vif found for mgmt frame\n");
ieee80211_free_txskb(ar->hw, skb);
continue;
}
- arvif = ath11k_vif_to_arvif(info->control.vif);
+ arvif = ath11k_vif_to_arvif(skb_cb->vif);
if (ar->allocated_vdev_map & (1LL << arvif->vdev_id) &&
arvif->is_started) {
ret = ath11k_mac_mgmt_tx_wmi(ar, arvif, skb);
@@ -4004,8 +4003,8 @@ static void ath11k_mgmt_over_wmi_tx_work(struct work_struct *work)
}
} else {
ath11k_warn(ar->ab,
- "dropping mgmt frame for vdev %d, flags 0x%x is_started %d\n",
- arvif->vdev_id, info->control.flags,
+ "dropping mgmt frame for vdev %d, is_started %d\n",
+ arvif->vdev_id,
arvif->is_started);
ieee80211_free_txskb(ar->hw, skb);
}
@@ -4053,10 +4052,13 @@ static void ath11k_mac_op_tx(struct ieee80211_hw *hw,
struct ieee80211_vif *vif = info->control.vif;
struct ath11k_vif *arvif = ath11k_vif_to_arvif(vif);
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)skb->data;
+ u32 info_flags = info->flags;
bool is_prb_rsp;
int ret;
- if (info->flags & IEEE80211_TX_CTL_HW_80211_ENCAP) {
+ skb_cb->vif = vif;
+
+ if (info_flags & IEEE80211_TX_CTL_HW_80211_ENCAP) {
skb_cb->flags |= ATH11K_SKB_HW_80211_ENCAP;
} else if (ieee80211_is_mgmt(hdr->frame_control)) {
is_prb_rsp = ieee80211_is_probe_resp(hdr->frame_control);
--
2.29.2
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 <[email protected]>
---
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 0296ba925455..9052fdd9837f 100644
--- a/drivers/net/wireless/ath/ath11k/mac.c
+++ b/drivers/net/wireless/ath/ath11k/mac.c
@@ -4056,6 +4056,7 @@ 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 (info_flags & IEEE80211_TX_CTL_HW_80211_ENCAP) {
--
2.29.2