From patchwork Fri Jun 9 09:37:44 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Remi Pommarel X-Patchwork-Id: 691118 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C9048C7EE2E for ; Fri, 9 Jun 2023 09:41:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241774AbjFIJln (ORCPT ); Fri, 9 Jun 2023 05:41:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33508 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241771AbjFIJlR (ORCPT ); Fri, 9 Jun 2023 05:41:17 -0400 Received: from relay1-d.mail.gandi.net (relay1-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::221]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1A80D76B4; Fri, 9 Jun 2023 02:36:00 -0700 (PDT) X-GND-Sasl: repk@triplefau.lt X-GND-Sasl: repk@triplefau.lt X-GND-Sasl: repk@triplefau.lt X-GND-Sasl: repk@triplefau.lt X-GND-Sasl: repk@triplefau.lt X-GND-Sasl: repk@triplefau.lt Received: by mail.gandi.net (Postfix) with ESMTPSA id E5ECC24000C; Fri, 9 Jun 2023 09:34:55 +0000 (UTC) From: Remi Pommarel To: =?utf-8?q?Toke_H=C3=B8iland-J=C3=B8rgensen?= , Kalle Valo , Jouni Malinen Cc: linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org, Remi Pommarel Subject: [PATCH] ath9k: Fix possible stall on ath9k_txq_list_has_key() Date: Fri, 9 Jun 2023 11:37:44 +0200 Message-Id: <20230609093744.1985-1-repk@triplefau.lt> X-Mailer: git-send-email 2.40.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org 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 Tested-by: Nicolas Escande Acked-by: Toke Høiland-Jørgensen --- 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 a4197c14f0a9..7f9f06ea8a05 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);