4.20-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 553a7cca769d551f1317186760631487c47e23bf ]
This issue arise in a race condition between ath10k_sta_state() and ath10k_htt_fetch_peer_stats(), explained in below scenario
Steps: 1. In ath10k_sta_state(), arsta->tx_stats get deallocated before peer deletion when the station moves from IEEE80211_STA_NONE to IEEE80211_STA_NOTEXIST state. 2. Meanwhile ath10k receive HTT_T2H_MSG_TYPE_PEER_STATS message. In ath10k_htt_fetch_peer_stats(), arsta->tx_stats get accessed after the peer validation check.
Since arsta->tx_stats get freed before the peer deletion [1]. ath10k_htt_fetch_peer_stats() ended up in "use after free" situation.
Fixed this issue by moving the arsta->tx_stats free handling after the peer deletion. so that ath10k_htt_fetch_peer_stats() will not end up in "use after free" situation.
Kernel Panic:
Unable to handle kernel NULL pointer dereference at virtual address 00000286 pgd = d8754000 [00000286] *pgd=00000000 Internal error: Oops: 5 [#1] PREEMPT SMP ARM ... CPU: 0 PID: 6245 Comm: hostapd Not tainted task: dc44cac0 ti: d4a38000 task.ti: d4a38000 PC is at kmem_cache_alloc+0x7c/0x114 LR is at ath10k_sta_state+0x190/0xd58 [ath10k_core] pc : [<c02bdc50>] lr : [<bf916b78>] psr: 20000013 sp : d4a39b88 ip : 00000000 fp : 00000001 r10: 00000000 r9 : 1d3bc000 r8 : 00000dc0 r7 : 000080d0 r6 : d4a38000 r5 : dd401b00 r4 : 00000286 r3 : 00000000 r2 : d4a39ba0 r1 : 000080d0 r0 : dd401b00 Flags: nzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user Control: 10c5787d Table: 5a75406a DAC: 00000015 Process hostapd (pid: 6245, stack limit = 0xd4a38238) Stack: (0xd4a39b88 to 0xd4a3a000) ... [<c02bdc50>] (kmem_cache_alloc) from [<bf916b78>] (ath10k_sta_state+0x190/0xd58 [ath10k_core]) [<bf916b78>] (ath10k_sta_state [ath10k_core]) from [<bf870d4c>] (sta_info_insert_rcu+0x418/0x61c [mac80211]) [<bf870d4c>] (sta_info_insert_rcu [mac80211]) from [<bf88634c>] (ieee80211_add_station+0xf0/0x134 [mac80211]) [<bf88634c>] (ieee80211_add_station [mac80211]) from [<bf83f3c4>] (nl80211_new_station+0x330/0x36c [cfg80211]) [<bf83f3c4>] (nl80211_new_station [cfg80211]) from [<bf6c4040>] (extack_doit+0x2c/0x74 [compat]) [<bf6c4040>] (extack_doit [compat]) from [<c05c285c>] (genl_rcv_msg+0x274/0x30c) [<c05c285c>] (genl_rcv_msg) from [<c05c1d98>] (netlink_rcv_skb+0x58/0xac) [<c05c1d98>] (netlink_rcv_skb) from [<c05c25d4>] (genl_rcv+0x20/0x34) [<c05c25d4>] (genl_rcv) from [<c05c1750>] (netlink_unicast+0x11c/0x204) [<c05c1750>] (netlink_unicast) from [<c05c1be0>] (netlink_sendmsg+0x30c/0x370) [<c05c1be0>] (netlink_sendmsg) from [<c0587e90>] (sock_sendmsg+0x70/0x84) [<c0587e90>] (sock_sendmsg) from [<c058970c>] (___sys_sendmsg.part.3+0x188/0x228) [<c058970c>] (___sys_sendmsg.part.3) from [<c058a594>] (__sys_sendmsg+0x4c/0x70) [<c058a594>] (__sys_sendmsg) from [<c0208c80>] (ret_fast_syscall+0x0/0x44) Code: ebfffec1 e1a04000 ea00001b e5953014 (e7940003) ath10k_pci 0000:01:00.0: SWBA overrun on vdev 0, skipped old beacon
Hardware tested: QCA9984 Firmware tested: 10.4-3.6.0.1-00004
Fixes: a904417fc ("ath10k: add extended per sta tx statistics support") Signed-off-by: Karthikeyan Periyasamy periyasa@codeaurora.org Signed-off-by: Kalle Valo kvalo@codeaurora.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/wireless/ath/ath10k/mac.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c index b4764fee4751..6436dc229be5 100644 --- a/drivers/net/wireless/ath/ath10k/mac.c +++ b/drivers/net/wireless/ath/ath10k/mac.c @@ -6387,11 +6387,6 @@ static int ath10k_sta_state(struct ieee80211_hw *hw, "mac vdev %d peer delete %pM sta %pK (sta gone)\n", arvif->vdev_id, sta->addr, sta);
- if (ath10k_debug_is_extd_tx_stats_enabled(ar)) { - kfree(arsta->tx_stats); - arsta->tx_stats = NULL; - } - if (sta->tdls) { ret = ath10k_mac_tdls_peer_update(ar, arvif->vdev_id, sta, @@ -6431,6 +6426,11 @@ static int ath10k_sta_state(struct ieee80211_hw *hw, } spin_unlock_bh(&ar->data_lock);
+ if (ath10k_debug_is_extd_tx_stats_enabled(ar)) { + kfree(arsta->tx_stats); + arsta->tx_stats = NULL; + } + for (i = 0; i < ARRAY_SIZE(sta->txq); i++) ath10k_mac_txq_unref(ar, sta->txq[i]);