From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f182.google.com (mail-pf1-f182.google.com [209.85.210.182]) (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 6E1943321AF for ; Fri, 28 Nov 2025 16:07:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764346024; cv=none; b=Y0Sj5XJkBKSnZWKX+cYFuQ5k038HxJI5jD8ndeFD+0GPFHyzsXGjYFbKby0DPT74MyLAP3I6oGA0r2ta0LlJvycOILr7TOA7d6shJ2NoniAxj0nmvf3gsJ3QzS4fk/aFHHNiH06PkBrugXcr8uStkAOntIw8ioCFMZRowQZ9a90= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764346024; c=relaxed/simple; bh=wtM3KGXEQuicJ8O+1w9NeLqs1Q3c/AYVobYXG6O4xkU=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=BuRskWgVo/wLeuUeOU6zXl/Vw++A92754hH8GiDI7EckyN/UN9hLTH5eY3V4tBtAwy+6mdjBSFf+D/+n5iz/lWsV6DxewApWUfh51EdlX5irgVrEl95jNYQDChm5SXkBMYJmK7vbT2viX4TvQYnVfnnumt/7RIxmU0ylM73Iw9o= 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=IhOXafUE; arc=none smtp.client-ip=209.85.210.182 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="IhOXafUE" Received: by mail-pf1-f182.google.com with SMTP id d2e1a72fcca58-7baf61be569so2419201b3a.3 for ; Fri, 28 Nov 2025 08:07:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1764346022; x=1764950822; 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=avVd2rCSlmy3mzSueRF3eaj+JsVil8OR/Q+bsjGDE3A=; b=IhOXafUEhg4evsLMn2hs+lf5f7rJn0H5MXvh51TQxLlZX/mxhGQw4mCtc+rlm9Kjgz y/k5zQwKyWO8Gx2kc3dLeByJpJfoPrK5FIyNHC7RPcRF0gONBUAn00Tg0P342NyG3j/5 SBNhpupqFdisc9BZ4BwPtKnDYQBhTp3+vtI68br+Z6UUPpSj1HcvZn2CdBRcZUdph8u9 0RMo5ekODzHm2FD+zhh01WVs5NnWYxGQnnjnKqaOaV3l5+iOliuAm3RBagWQ3xJRhI7E wrLqhyqWy9syPa4UkGNBj0RTn6Mb21Lw4fB5Zl4GEOEHvNL7jQm4qYzZDVPM0yNuMtTO 9AaQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1764346022; x=1764950822; 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=avVd2rCSlmy3mzSueRF3eaj+JsVil8OR/Q+bsjGDE3A=; b=tmMTL9qQTQgCFw3hSGuS9tsPaA8kV0daL1bV0gnQxaPCt0YO9sewVBmmAftiK2imR1 lXjhZp4qJKmjon4PJc3ES8hnxfevMiKSJylcdAwQnFk+OksNRH/Y/mhG6aH1/m55JQPm vCgKpSsHhHtJH10wAWJSFw1nPG8QQqSLtb0PrT6kiYlh4sD/lyqWeyVELjLvkQgwP4Ls zUP0p1huvIHwnBeUrznE6kVEAhhhMIkmvFdQ1SfmEM26+73cR7nx90xvO0LySu1+H5Io zD7K4/RKU1rx71J3CsZlWa8RtxLhetnKQKRnKBHg2HbaFcBcayJcJXV6HDWNKMYWaX73 8Qyg== X-Gm-Message-State: AOJu0YwFSwRARtjkBjf4LYwAeL/bzYnaDT+sVic9JLeQEAXICBQFHEn7 kJLulIWRZXMbXUDd709oEHksnPiRNavPkMKMDDtRGSITmKspG3Rnb0eJJPCbEJOhqw4WhA== X-Gm-Gg: ASbGncs/4mGkxTH14gJlMA7HmthTlGqv0kRNNjpoL8r1q8I0evrl3C+aJtY6+pIPQ+u xnIGMYgwJyP3Cr5m0AEqtK5OLrc8jsADP1jpUibe7frMyShmcb4xC7MAwI8yiu40R33YOdfqqPg EatkUg5VFnX+b7hwKWts2B8KarHeRKKOmlJ6ywBcF0C7tZlWoWCT/Hi4h7pM3Czln6Qc7Oyyesj e08q1VL72lI9Xs6qnzJVkfnNwcyRJ00xDyOBFPFwVAl3AAgHO/qEF+Z+GWXbdDObi2/QWxlAZM5 p0Ubku7PbsAyQRKHjIXhDSOga1PqjQcgVkUcg6O+4+1+O8RxzvHkiAH1LoFw6gOHaj7qbhBoWlz RPTLJcv1vY/qJjtaiQZGz2GyIf+9AUcCQHqX3o9rPiNWXd6PH/CFq2s62J+DAgZgree2SjzZ8z6 AWetWx/MiGdy2CMMwLVUJSxrDwveoIe6vhwAdSlg== X-Google-Smtp-Source: AGHT+IFbb5wRaCswqOfBZvptqiaZuYa9cCWiPzI9C94VNg3d8rKHwc6PhwU1RUpFCGSPXAzo6Ott0w== X-Received: by 2002:a05:6a00:22cb:b0:7aa:2cc6:8c38 with SMTP id d2e1a72fcca58-7c58c2abb3dmr27067471b3a.2.1764346022026; Fri, 28 Nov 2025 08:07:02 -0800 (PST) Received: from name2965-Precision-7820-Tower.. ([121.185.186.233]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-7d15f26f11fsm5408499b3a.50.2025.11.28.08.06.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 28 Nov 2025 08:07:00 -0800 (PST) From: Jeongjun Park To: stable@vger.kernel.org Cc: gregkh@linuxfoundation.org, tglx@linutronix.de, Julia.Lawall@inria.fr, akpm@linux-foundation.org, anna-maria@linutronix.de, arnd@arndb.de, linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org, linux@roeck-us.net, luiz.dentz@gmail.com, marcel@holtmann.org, maz@kernel.org, peterz@infradead.org, rostedt@goodmis.org, sboyd@kernel.org, viresh.kumar@linaro.org, aha310510@gmail.com, linux-staging@lists.linux.dev, Jacob Keller Subject: [PATCH 5.15.y 14/14] Bluetooth: hci_qca: Fix the teardown problem for real Date: Sat, 29 Nov 2025 01:05:39 +0900 Message-Id: <20251128160539.358938-15-aha310510@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20251128160539.358938-1-aha310510@gmail.com> References: <20251128160539.358938-1-aha310510@gmail.com> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Thomas Gleixner [ Upstream commit e0d3da982c96aeddc1bbf1cf9469dbb9ebdca657 ] While discussing solutions for the teardown problem which results from circular dependencies between timers and workqueues, where timers schedule work from their timer callback and workqueues arm the timers from work items, it was discovered that the recent fix to the QCA code is incorrect. That commit fixes the obvious problem of using del_timer() instead of del_timer_sync() and reorders the teardown calls to destroy_workqueue(wq); del_timer_sync(t); This makes it less likely to explode, but it's still broken: destroy_workqueue(wq); /* After this point @wq cannot be touched anymore */ ---> timer expires queue_work(wq) <---- Results in a NULL pointer dereference deep in the work queue core code. del_timer_sync(t); Use the new timer_shutdown_sync() function to ensure that the timers are disarmed, no timer callbacks are running and the timers cannot be armed again. This restores the original teardown sequence: timer_shutdown_sync(t); destroy_workqueue(wq); which is now correct because the timer core silently ignores potential rearming attempts which can happen when destroy_workqueue() drains pending work before mopping up the workqueue. Fixes: 72ef98445aca ("Bluetooth: hci_qca: Use del_timer_sync() before freeing") Signed-off-by: Thomas Gleixner Tested-by: Guenter Roeck Reviewed-by: Jacob Keller Reviewed-by: Anna-Maria Behnsen Acked-by: Luiz Augusto von Dentz Link: https://lore.kernel.org/all/87iljhsftt.ffs@tglx Link: https://lore.kernel.org/r/20221123201625.435907114@linutronix.de Signed-off-by: Jeongjun Park --- drivers/bluetooth/hci_qca.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c index 66f416f59a8d..204ba1de624d 100644 --- a/drivers/bluetooth/hci_qca.c +++ b/drivers/bluetooth/hci_qca.c @@ -710,9 +710,15 @@ static int qca_close(struct hci_uart *hu) skb_queue_purge(&qca->tx_wait_q); skb_queue_purge(&qca->txq); skb_queue_purge(&qca->rx_memdump_q); + /* + * Shut the timers down so they can't be rearmed when + * destroy_workqueue() drains pending work which in turn might try + * to arm a timer. After shutdown rearm attempts are silently + * ignored by the timer core code. + */ + timer_shutdown_sync(&qca->tx_idle_timer); + timer_shutdown_sync(&qca->wake_retrans_timer); destroy_workqueue(qca->workqueue); - del_timer_sync(&qca->tx_idle_timer); - del_timer_sync(&qca->wake_retrans_timer); qca->hu = NULL; kfree_skb(qca->rx_skb); --