From e44de90453bb2b46a523df78c39eb896bab35dcd Mon Sep 17 00:00:00 2001
From: Govindaraj Saminathan <quic_gsaminat@quicinc.com>
Date: Tue, 29 Nov 2022 13:04:02 +0200
Subject: [PATCH] wifi: ath11k: Fix race condition with struct
htt_ppdu_stats_info
A crash happens when running the traffic with multiple clients:
Crash Signature : Unable to handle kernel paging request at
virtual address ffffffd700970918 During the crash, PC points to
"ieee80211_tx_rate_update+0x30/0x68 [mac80211]"
LR points to "ath11k_dp_htt_htc_t2h_msg_handler+0x5a8/0x8a0 [ath11k]".
Struct ppdu_stats_info is allocated and accessed from event callback via copy
engine tasklet, this has a problem when freeing it from ath11k_mac_op_stop().
Use data_lock during entire ath11k_dp_htt_get_ppdu_desc() call to protect
struct htt_ppdu_stats_info access and to avoid race condition when accessing it
from ath11k_mac_op_stop().
Tested-on: IPQ8074 hw2.0 AHB WLAN.HK.2.7.0.1-01744-QCAHKSWPL_SILICONZ-1
Signed-off-by: Govindaraj Saminathan <quic_gsaminat@quicinc.com>
Co-developed-by: Karthikeyan Kathirvel <quic_kathirve@quicinc.com>
Signed-off-by: Karthikeyan Kathirvel <quic_kathirve@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20221124071104.22506-1-quic_kathirve@quicinc.com
---
drivers/net/wireless/ath/ath11k/dp_rx.c | 22 +++++++++++-----------
1 file changed, 11 insertions(+), 11 deletions(-)
diff --git a/drivers/net/wireless/ath/ath11k/dp_rx.c b/drivers/net/wireless/ath/ath11k/dp_rx.c
index c5a4c34d77499..c33e68ff707ab 100644
--- a/drivers/net/wireless/ath/ath11k/dp_rx.c
+++ b/drivers/net/wireless/ath/ath11k/dp_rx.c
@@ -1535,13 +1535,12 @@ struct htt_ppdu_stats_info *ath11k_dp_htt_get_ppdu_desc(struct ath11k *ar,
{
struct htt_ppdu_stats_info *ppdu_info;
- spin_lock_bh(&ar->data_lock);
+ lockdep_assert_held(&ar->data_lock);
+
if (!list_empty(&ar->ppdu_stats_info)) {
list_for_each_entry(ppdu_info, &ar->ppdu_stats_info, list) {
- if (ppdu_info->ppdu_id == ppdu_id) {
- spin_unlock_bh(&ar->data_lock);
+ if (ppdu_info->ppdu_id == ppdu_id)
return ppdu_info;
- }
}
if (ar->ppdu_stat_list_depth > HTT_PPDU_DESC_MAX_DEPTH) {
@@ -1553,16 +1552,13 @@ struct htt_ppdu_stats_info *ath11k_dp_htt_get_ppdu_desc(struct ath11k *ar,
kfree(ppdu_info);
}
}
- spin_unlock_bh(&ar->data_lock);
ppdu_info = kzalloc(sizeof(*ppdu_info), GFP_ATOMIC);
if (!ppdu_info)
return NULL;
- spin_lock_bh(&ar->data_lock);
list_add_tail(&ppdu_info->list, &ar->ppdu_stats_info);
ar->ppdu_stat_list_depth++;
- spin_unlock_bh(&ar->data_lock);
return ppdu_info;
}
@@ -1586,16 +1582,17 @@ static int ath11k_htt_pull_ppdu_stats(struct ath11k_base *ab,
ar = ath11k_mac_get_ar_by_pdev_id(ab, pdev_id);
if (!ar) {
ret = -EINVAL;
- goto exit;
+ goto out;
}
if (ath11k_debugfs_is_pktlog_lite_mode_enabled(ar))
trace_ath11k_htt_ppdu_stats(ar, skb->data, len);
+ spin_lock_bh(&ar->data_lock);
ppdu_info = ath11k_dp_htt_get_ppdu_desc(ar, ppdu_id);
if (!ppdu_info) {
ret = -EINVAL;
- goto exit;
+ goto out_unlock_data;
}
ppdu_info->ppdu_id = ppdu_id;
@@ -1604,10 +1601,13 @@ static int ath11k_htt_pull_ppdu_stats(struct ath11k_base *ab,
(void *)ppdu_info);
if (ret) {
ath11k_warn(ab, "Failed to parse tlv %d\n", ret);
- goto exit;
+ goto out_unlock_data;
}
-exit:
+out_unlock_data:
+ spin_unlock_bh(&ar->data_lock);
+
+out:
rcu_read_unlock();
return ret;
--
2.30.2