From nobody Fri Jun 19 22:17:01 2026 Received: from mail-pl1-f176.google.com (mail-pl1-f176.google.com [209.85.214.176]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0E5AD2D73A1 for ; Tue, 21 Apr 2026 17:26:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.176 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776792380; cv=none; b=PlrH+CXQnMgcnCLkoWy77hQYae2f4E9raC+aiCTwHNVcAhBrBCqktQtBVhN0CWR+BNL13EThuLARyUygLc0kmBEcrvapsNEOWRmInB/tpJUiXeHF6fLcHWP3cqqlpeBLMy68cteeVKeiXW4znfj4PJtq3Prb4EChqqfhlWtzu2Q= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776792380; c=relaxed/simple; bh=army6csuzlkfmCzKW9Q6UiVBt0h02XrDzPZdS88qN00=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fPOw5rsLBhUN93WizHd96OZR61kteuW8iJ9A30UM5Rkk9jVxZ+ir3ErdaRnhah3xNLVwQlaMfr9tMGy1KTAbUfU+vOQQidORCibfo4AVVYX7BiXCLHc0g1KLXWvVAz07MX5tExRsUYhJaWh+59YoKOyOdVJAhCps1fGdJTWkmnk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=YtyJjmlJ; arc=none smtp.client-ip=209.85.214.176 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="YtyJjmlJ" Received: by mail-pl1-f176.google.com with SMTP id d9443c01a7336-2aaf59c4f7cso20876955ad.1 for ; Tue, 21 Apr 2026 10:26:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1776792378; x=1777397178; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=Uu5+POdFqqclIWWOEr3Sv9HNAu+bDuUYEserSDIYQ6I=; b=YtyJjmlJxdQ/C/xhJkJ7NDgE9aJF/VGJWXK+/2rXjGlZqOykv1AZ4nh8HrrDO3Cb5h AK/cG417KP4s7ImNbdz2jXIRLHduZpZDFb3a9ynS5lD2E0kzsNfOuWZkzsRWxSZHux82 pyxeEmUqmxPJV9B9ZgovJV+K5eEyAb77PE+oSz7gPkBQVXoy10RWhXA2+dkm4YPb/9yX YxIrZngJiPRFQTH+NHhDYqygObGQAOsexwsGgAYR/HjbioMpxn3EGK7Xvo5vzsT7d8ao kJloHzvVYCC5wfilrRszYx16dXm+BdcBGmiZZPfaNECXIjo90JEe3mZep7aG5s2QLlLs PJ4g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776792378; x=1777397178; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=Uu5+POdFqqclIWWOEr3Sv9HNAu+bDuUYEserSDIYQ6I=; b=WNl2ubVhI18tjo7h/+b5+CFI7Jg7swsrJMvKIZShejbNfh3sfUubEZk+WNt+7mYSSA PYAr4mcENWptZGb+xrMKAoGuh2BB3UEwEYEPCby7ZrPmeNdwzfE/aLb///L/P+u18gN/ iJVMEIVBZhfXhNECiGWFciYR5/bzZCp8sBIbvISyRO3HE2+SPzgg9Zw8NmrWEHr2p9/E wnu+CFOXQQ7B2FXbGEkAH2tVDgE6c6au4iU2RZzQMcOHTlrxbjARhPZURNjYeNZHJCc3 NAqjEz5wAiTvhJOCLyGcoMkb7Xe7W8rR241+fW9OJP2OE8QQSdW3hCmEZu21pzmLz3IQ Qjxw== X-Forwarded-Encrypted: i=1; AFNElJ+MjGzQZe3/Wk6w3pjBFVJDkxeSwtBxa9riEYpQabUSqafRT9Q0t30DfnIBpovghiTrB23VSWyf1ZvgICA=@vger.kernel.org X-Gm-Message-State: AOJu0Yz7hn6RSOPzA3m6XjTWmpArnxh1HUzxui0jGmXpUd3gLsY26PYh XNYXY4Zi7WNMsZ+yFTFLiWngVblPVqbOKuE/8fHquA8SCTbGNv7EBnbc X-Gm-Gg: AeBDiev+Si3rADPIAvzH2yNvBHq3jpBIOC2bdnj9AMb4TmCnSTUr0HBKiOdqbzF43VJ AGPo2Zx9WQerIiB3bht/N+OB7lHoxuN/x0mdftkyRr0UvE8gwEwWdAA6niVnkM5WKVvFd/mq3XL xziOMTkDwxCsTkybrOtH2KxNy633gO6PMSxDPcH/SOoF/kP9gMb7XXMFvuoxyqYeQZBPMr2D4ZB IhQqFRvgDeKNs1Ix1CFGkMHZDUVv6HcChcIKAf9l3zNMQK+NnuR47vdOUC6gnH2rb1W+V4ux1vD 7o8viICaKh4iZkedhRWgN+MMtT8sC0m1lPOQYClTKVdJ81b3w8ko2KLPRPewNeKIDm9QFbhx+MF quBFNB2X9w2Q3BD57TQZKZuCR7kOdkZXN6ECRRuM0cO9+ikYnPkDl6gktER9hmEJZRCa2sZA5aM BUzx2rkqyvnTiDycpxsV+xSaW3CB/V+xL2X+Z3hROyWf0J4Hg= X-Received: by 2002:a17:902:db0d:b0:2b2:4fe3:7b89 with SMTP id d9443c01a7336-2b5f9f52879mr182995625ad.38.1776792378433; Tue, 21 Apr 2026 10:26:18 -0700 (PDT) Received: from lenovo.localdomain ([123.110.133.16]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2b5faa507cbsm144897015ad.37.2026.04.21.10.26.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 21 Apr 2026 10:26:18 -0700 (PDT) From: Yu-Hsiang Tseng To: Jeff Johnson , ath12k@lists.infradead.org Cc: Baochen Qiang , Rameshkumar Sundaram , Kalle Valo , Sebastian Andrzej Siewior , Clark Williams , Steven Rostedt , linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev Subject: [PATCH v2] wifi: ath12k: fix false positive RCU warnings on PREEMPT_RT Date: Wed, 22 Apr 2026 01:25:00 +0800 Message-ID: <20260421172500.1050754-1-asas1asas200@gmail.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <4cdf2e61-fe69-4168-9df7-55bb71585dfe@oss.qualcomm.com> References: <4cdf2e61-fe69-4168-9df7-55bb71585dfe@oss.qualcomm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Two functions in ath12k assert that the caller holds an RCU read lock: ath12k_mac_get_arvif() and ath12k_p2p_noa_update_vdev_iter(). Both use: WARN_ON(!rcu_read_lock_any_held()); On PREEMPT_RT kernels built with CONFIG_PROVE_RCU=3Dn, this produces a false positive splat whenever these functions are invoked from paths that do hold the RCU read lock (e.g. firmware stats processing or mac80211 interface iteration). Root cause: - On !PROVE_RCU, rcu_read_lock_any_held() is a static inline that returns !preemptible() as a proxy for "in an RCU read section". - On PREEMPT_RT, rcu_read_lock() does not disable preemption. A task can therefore be preemptible while legitimately holding an RCU read lock. - Callers such as ath12k_wmi_tlv_rssi_chain_parse() (via guard(rcu)()) and ieee80211_iterate_active_interfaces_atomic() do hold the RCU read lock, so these warnings are incorrect. Typical splat seen on a WCN7850 station with periodic fw stats processing: WARNING: drivers/net/wireless/ath/ath12k/mac.c:791 at ath12k_mac_get_arvif+0x9e/0xd0 [ath12k] Tainted: G W O 6.19.13-rt #1 PREEMPT_RT Call Trace: ath12k_wmi_tlv_rssi_chain_parse+0x69/0x170 [ath12k] ath12k_wmi_tlv_iter+0x7f/0x120 [ath12k] ath12k_wmi_tlv_fw_stats_parse+0x342/0x6b0 [ath12k] ath12k_wmi_op_rx+0xe9e/0x3150 [ath12k] ath12k_htc_rx_completion_handler+0x3df/0x5b0 [ath12k] ath12k_ce_per_engine_service+0x325/0x3e0 [ath12k] ath12k_pci_ce_workqueue+0x20/0x40 [ath12k] Replace the WARN_ON() with RCU_LOCKDEP_WARN(), which is gated on debug_lockdep_rcu_enabled() and therefore compiles out entirely when PROVE_RCU is disabled. PROVE_RCU kernels continue to get the full lockdep-based check. Fixes: 3dd2c68f206e ("wifi: ath12k: prepare vif data structure for MLO hand= ling") Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.1.c5-00302-QCAHMTSWPL_V1.0_V2.0_SIL= ICONZ-1.115823.3 Suggested-by: Baochen Qiang Signed-off-by: Yu-Hsiang Tseng Reviewed-by: Baochen Qiang Reviewed-by: Rameshkumar Sundaram --- Changes in v2: - Also fix the same WARN_ON() in ath12k_p2p_noa_update_vdev_iter() (suggested by Baochen Qiang) - Update commit message to cover both call sites Link to v1: https://lore.kernel.org/ath12k/20260420161049.695518-1-asas1asa= s200@gmail.com/ drivers/net/wireless/ath/ath12k/mac.c | 3 ++- drivers/net/wireless/ath/ath12k/p2p.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/wireless/ath/ath12k/mac.c b/drivers/net/wireless/a= th/ath12k/mac.c index fbdfe6424fd7..a772a5b6adc9 100644 --- a/drivers/net/wireless/ath/ath12k/mac.c +++ b/drivers/net/wireless/ath/ath12k/mac.c @@ -788,7 +788,8 @@ struct ath12k_link_vif *ath12k_mac_get_arvif(struct ath= 12k *ar, u32 vdev_id) =20 /* To use the arvif returned, caller must have held rcu read lock. */ - WARN_ON(!rcu_read_lock_any_held()); + RCU_LOCKDEP_WARN(!rcu_read_lock_any_held(), + "RCU read lock not held"); arvif_iter.vdev_id =3D vdev_id; arvif_iter.ar =3D ar; =20 diff --git a/drivers/net/wireless/ath/ath12k/p2p.c b/drivers/net/wireless/a= th/ath12k/p2p.c index 59589748f1a8..caa92612372b 100644 --- a/drivers/net/wireless/ath/ath12k/p2p.c +++ b/drivers/net/wireless/ath/ath12k/p2p.c @@ -123,7 +123,8 @@ static void ath12k_p2p_noa_update_vdev_iter(void *data,= u8 *mac, struct ath12k_p2p_noa_arg *arg =3D data; struct ath12k_link_vif *arvif; =20 - WARN_ON(!rcu_read_lock_any_held()); + RCU_LOCKDEP_WARN(!rcu_read_lock_any_held(), + "RCU read lock not held"); arvif =3D &ahvif->deflink; if (!arvif->is_created || arvif->ar !=3D arg->ar || arvif->vdev_id !=3D a= rg->vdev_id) return; --=20 2.53.0