From: Remi Pommarel repk@triplefau.lt
[ Upstream commit 75086cc6dee046e3fbb3dba148b376d8802f83bc ]
On EDMA capable hardware, ath9k_txq_list_has_key() can enter infinite loop if it is called while all txq_fifos have packets that use different key that the one we are looking for. Fix it by exiting the loop if all txq_fifos have been checked already.
Because this loop is called under spin_lock_bh() (see ath_txq_lock) it causes the following rcu stall:
rcu: INFO: rcu_sched self-detected stall on CPU ath10k_pci 0000:01:00.0: failed to read temperature -11 rcu: 1-....: (5254 ticks this GP) idle=189/1/0x4000000000000002 softirq=8442983/8442984 fqs=2579 (t=5257 jiffies g=17983297 q=334) Task dump for CPU 1: task:hostapd state:R running task stack: 0 pid: 297 ppid: 289 flags:0x0000000a Call trace: dump_backtrace+0x0/0x170 show_stack+0x1c/0x24 sched_show_task+0x140/0x170 dump_cpu_task+0x48/0x54 rcu_dump_cpu_stacks+0xf0/0x134 rcu_sched_clock_irq+0x8d8/0x9fc update_process_times+0xa0/0xec tick_sched_timer+0x5c/0xd0 __hrtimer_run_queues+0x154/0x320 hrtimer_interrupt+0x120/0x2f0 arch_timer_handler_virt+0x38/0x44 handle_percpu_devid_irq+0x9c/0x1e0 handle_domain_irq+0x64/0x90 gic_handle_irq+0x78/0xb0 call_on_irq_stack+0x28/0x38 do_interrupt_handler+0x54/0x5c el1_interrupt+0x2c/0x4c el1h_64_irq_handler+0x14/0x1c el1h_64_irq+0x74/0x78 ath9k_txq_has_key+0x1bc/0x250 [ath9k] ath9k_set_key+0x1cc/0x3dc [ath9k] drv_set_key+0x78/0x170 ieee80211_key_replace+0x564/0x6cc ieee80211_key_link+0x174/0x220 ieee80211_add_key+0x11c/0x300 nl80211_new_key+0x12c/0x330 genl_family_rcv_msg_doit+0xbc/0x11c genl_rcv_msg+0xd8/0x1c4 netlink_rcv_skb+0x40/0x100 genl_rcv+0x3c/0x50 netlink_unicast+0x1ec/0x2c0 netlink_sendmsg+0x198/0x3c0 ____sys_sendmsg+0x210/0x250 ___sys_sendmsg+0x78/0xc4 __sys_sendmsg+0x4c/0x90 __arm64_sys_sendmsg+0x28/0x30 invoke_syscall.constprop.0+0x60/0x100 do_el0_svc+0x48/0xd0 el0_svc+0x14/0x50 el0t_64_sync_handler+0xa8/0xb0 el0t_64_sync+0x158/0x15c
This rcu stall is hard to reproduce as is, but changing ATH_TXFIFO_DEPTH from 8 to 2 makes it reasonably easy to reproduce.
Fixes: ca2848022c12 ("ath9k: Postpone key cache entry deletion for TXQ frames reference it") Signed-off-by: Remi Pommarel repk@triplefau.lt Tested-by: Nicolas Escande nico.escande@gmail.com Acked-by: Toke Høiland-Jørgensen toke@toke.dk Signed-off-by: Kalle Valo quic_kvalo@quicinc.com Link: https://lore.kernel.org/r/20230609093744.1985-1-repk@triplefau.lt Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/wireless/ath/ath9k/main.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c index a4197c14f0a92..7f9f06ea8a05f 100644 --- a/drivers/net/wireless/ath/ath9k/main.c +++ b/drivers/net/wireless/ath/ath9k/main.c @@ -850,7 +850,7 @@ static bool ath9k_txq_list_has_key(struct list_head *txq_list, u32 keyix) static bool ath9k_txq_has_key(struct ath_softc *sc, u32 keyix) { struct ath_hw *ah = sc->sc_ah; - int i; + int i, j; struct ath_txq *txq; bool key_in_use = false;
@@ -868,8 +868,9 @@ static bool ath9k_txq_has_key(struct ath_softc *sc, u32 keyix) if (sc->sc_ah->caps.hw_caps & ATH9K_HW_CAP_EDMA) { int idx = txq->txq_tailidx;
- while (!key_in_use && - !list_empty(&txq->txq_fifo[idx])) { + for (j = 0; !key_in_use && + !list_empty(&txq->txq_fifo[idx]) && + j < ATH_TXFIFO_DEPTH; j++) { key_in_use = ath9k_txq_list_has_key( &txq->txq_fifo[idx], keyix); INCR(idx, ATH_TXFIFO_DEPTH);