From: Alexander Wetzel <alexander@xxxxxxxxxxxxxx> commit 69403bad97aa0162e3d7911b27e25abe774093df upstream. ieee80211_tx_ba_session_handle_start() may get NULL for sdata when a deauthentication is ongoing. Here a trace triggering the race with the hostapd test multi_ap_fronthaul_on_ap: (gdb) list *drv_ampdu_action+0x46 0x8b16 is in drv_ampdu_action (net/mac80211/driver-ops.c:396). 391 int ret = -EOPNOTSUPP; 392 393 might_sleep(); 394 395 sdata = get_bss_sdata(sdata); 396 if (!check_sdata_in_driver(sdata)) 397 return -EIO; 398 399 trace_drv_ampdu_action(local, sdata, params); 400 wlan0: moving STA 02:00:00:00:03:00 to state 3 wlan0: associated wlan0: deauthenticating from 02:00:00:00:03:00 by local choice (Reason: 3=DEAUTH_LEAVING) wlan3.sta1: Open BA session requested for 02:00:00:00:00:00 tid 0 wlan3.sta1: dropped frame to 02:00:00:00:00:00 (unauthorized port) wlan0: moving STA 02:00:00:00:03:00 to state 2 wlan0: moving STA 02:00:00:00:03:00 to state 1 wlan0: Removed STA 02:00:00:00:03:00 wlan0: Destroyed STA 02:00:00:00:03:00 BUG: unable to handle page fault for address: fffffffffffffb48 PGD 11814067 P4D 11814067 PUD 11816067 PMD 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 2 PID: 133397 Comm: kworker/u16:1 Tainted: G W 6.1.0-rc8-wt+ #59 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.0-20220807_005459-localhost 04/01/2014 Workqueue: phy3 ieee80211_ba_session_work [mac80211] RIP: 0010:drv_ampdu_action+0x46/0x280 [mac80211] Code: 53 48 89 f3 be 89 01 00 00 e8 d6 43 bf ef e8 21 46 81 f0 83 bb a0 1b 00 00 04 75 0e 48 8b 9b 28 0d 00 00 48 81 eb 10 0e 00 00 <8b> 93 58 09 00 00 f6 c2 20 0f 84 3b 01 00 00 8b 05 dd 1c 0f 00 85 RSP: 0018:ffffc900025ebd20 EFLAGS: 00010287 RAX: 0000000000000000 RBX: fffffffffffff1f0 RCX: ffff888102228240 RDX: 0000000080000000 RSI: ffffffff918c5de0 RDI: ffff888102228b40 RBP: ffffc900025ebd40 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000001 R11: 0000000000000000 R12: ffff888118c18ec0 R13: 0000000000000000 R14: ffffc900025ebd60 R15: ffff888018b7efb8 FS: 0000000000000000(0000) GS:ffff88817a600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: fffffffffffffb48 CR3: 0000000105228006 CR4: 0000000000170ee0 Call Trace: <TASK> ieee80211_tx_ba_session_handle_start+0xd0/0x190 [mac80211] ieee80211_ba_session_work+0xff/0x2e0 [mac80211] process_one_work+0x29f/0x620 worker_thread+0x4d/0x3d0 ? process_one_work+0x620/0x620 kthread+0xfb/0x120 ? kthread_complete_and_exit+0x20/0x20 ret_from_fork+0x22/0x30 </TASK> Signed-off-by: Alexander Wetzel <alexander@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20221230121850.218810-2-alexander@xxxxxxxxxxxxxx Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/mac80211/agg-tx.c | 6 +++++- net/mac80211/driver-ops.c | 3 +++ 2 files changed, 8 insertions(+), 1 deletion(-) --- a/net/mac80211/agg-tx.c +++ b/net/mac80211/agg-tx.c @@ -491,7 +491,7 @@ void ieee80211_tx_ba_session_handle_star { struct tid_ampdu_tx *tid_tx; struct ieee80211_local *local = sta->local; - struct ieee80211_sub_if_data *sdata = sta->sdata; + struct ieee80211_sub_if_data *sdata; struct ieee80211_ampdu_params params = { .sta = &sta->sta, .action = IEEE80211_AMPDU_TX_START, @@ -521,6 +521,7 @@ void ieee80211_tx_ba_session_handle_star */ synchronize_net(); + sdata = sta->sdata; params.ssn = sta->tid_seq[tid] >> 4; ret = drv_ampdu_action(local, sdata, ¶ms); tid_tx->ssn = params.ssn; @@ -534,6 +535,9 @@ void ieee80211_tx_ba_session_handle_star */ set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state); } else if (ret) { + if (!sdata) + return; + ht_dbg(sdata, "BA request denied - HW unavailable for %pM tid %d\n", sta->sta.addr, tid); --- a/net/mac80211/driver-ops.c +++ b/net/mac80211/driver-ops.c @@ -391,6 +391,9 @@ int drv_ampdu_action(struct ieee80211_lo might_sleep(); + if (!sdata) + return -EIO; + sdata = get_bss_sdata(sdata); if (!check_sdata_in_driver(sdata)) return -EIO;
