From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from extorris.mess.org (extorris.mess.org [92.243.27.206]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 85F9E334688; Fri, 4 Sep 2026 13:08:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=92.243.27.206 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788527292; cv=none; b=K3VQmK5iAxiWCtDEtr5C8IWsrjXvQt9xZTD59Rh6HjLU8m4pPBK1/VhBUk8H4Ig2SoH2cXAE6TIuW181UN5WavHXq1GxdDwckFzhReZGD2O9PJWVHM6iKoVfe/kOUN30B49FnocTnAu0ubgjwHD8F9qgStaRjwcyI3Nvvrm0Y40= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788527292; c=relaxed/simple; bh=Za8UtDCRpcoLldjKGS5+rPnf9qprec85BjwFh0wyNAA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=p3wwk4+tauXO6Eq2BJ5TxoBjlxPZzx+3J6sNq0Afonl4DW/HA+deApKMZ9F9xfJ4g2C9D4KzXXQ2bWcyhQfSqPWJwuXmgXwNZLaPJCxStTt3vw6QWxry6QgZxd0z8u1veHRGuRCHyHiyS0fqxx7YmYOhfZW8evwxK8BPOnFKOAU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=mess.org; spf=pass smtp.mailfrom=mess.org; dkim=pass (2048-bit key) header.d=mess.org header.i=@mess.org header.b=VXDf6MzO; dkim=pass (2048-bit key) header.d=mess.org header.i=@mess.org header.b=ebMJ0lo2; arc=none smtp.client-ip=92.243.27.206 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=mess.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mess.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=mess.org header.i=@mess.org header.b="VXDf6MzO"; dkim=pass (2048-bit key) header.d=mess.org header.i=@mess.org header.b="ebMJ0lo2" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=mess.org; s=2020; t=1788527282; bh=Za8UtDCRpcoLldjKGS5+rPnf9qprec85BjwFh0wyNAA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VXDf6MzOkhlzSCadEJ6yAviTFtR0TzYu97Sq8BI0lByWhuLKsz0JwR7pckN03d4xB BxOrak93sGTGPFlx8VKZ890+dY1ZoUqBxzlQXKlAQjrOmrH+tE5YPMQH83c1djri1P rlKh4rcxoZ2qFmQ/I+1HgLh7KV2xdYeajJbPcTnzcMJV+mTYTaqw0IbTRCqflNqnQq QpO3ET0DiUzC06YE8f8pK9WlU6/9jFfEfaP1ckA3UQzIyq4CnWkJQtxUu1TXTbcZJT X5zci/NdkOJYormjc1K2cjsNXfm8ukrB/xkfpBmAq01w7vENQgKNkflrm0uHYP0kjJ TLJSPehKtz4oA== Received: by extorris.mess.org (Postfix, from userid 1004) id C08F241464; Fri, 04 Sep 2026 14:08:02 +0100 (BST) X-Spam-Level: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=mess.org; s=2020; t=1788527280; bh=Za8UtDCRpcoLldjKGS5+rPnf9qprec85BjwFh0wyNAA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ebMJ0lo2ClgIoAc25Gkm4fqdcEmLstwC5qOFmykTcbafzdQjYnav/Shcj5z+DNx1r OMOy+IuSJdYYjpqkDhKM7PZE6bsF/WcCdAjiZFO52hbFvW3T6B4SzFr+hNUydKuIs8 FtzK/+yYxgjn9TpU034yRYHFisZ5ezNdsdPJhoMP2y/uHfD4w5FaYTy+KK/N5aGKzR zrF1SltyAlmqaPfx/E7bgHBUZxLCLZd10mUvkgdNyrC/DVlNajK5X9NKDIgOSPIh+I LLaPGTYOUIUMwgoH85sfBrRX3OillH49nV25/2kCVxktckOUjhSmyi15Un+nELY6Uc njcReBVdExftQ== Received: from maru.mess.org (hephaestus.mess.org [82.68.61.198]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by extorris.mess.org (Postfix) with ESMTPSA id F27774144F; Fri, 04 Sep 2026 14:07:59 +0100 (BST) From: Sean Young To: linux-media@vger.kernel.org, Sean Young , Mauro Carvalho Chehab Cc: Rik van Riel , stable@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v3 06/17] media: rc: mce_kbd: Fix inconsistent locking of keylock Date: Fri, 4 Sep 2026 14:07:34 +0100 Message-ID: <1dd7a367cf7b1bd57fed39832b3926570d34a8a5.1788526920.git.sean@mess.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit data->keylock is taken with spin_lock() in ir_mce_kbd_decode(), which runs in the raw IR decode kthread with local interrupts enabled, but with spin_lock_irqsave() in mce_kbd_rx_timeout(), the rx_timeout timer callback, which runs in softirq context. If the decode kthread is holding keylock via spin_lock() when a timer interrupt fires on the same CPU and the softirq runs mce_kbd_rx_timeout(), the softirq spins forever waiting for a lock that only the now-preempted kthread can release, while the kthread cannot run again until the softirq gives up the CPU. This deadlocks the CPU. Fixes: 53a62800efb2 ("media: rc: mce_kbd decoder: fix race condition") Signed-off-by: Sean Young Cc: stable@vger.kernel.org --- drivers/media/rc/ir-mce_kbd-decoder.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/media/rc/ir-mce_kbd-decoder.c b/drivers/media/rc/ir-mce_kbd-decoder.c index bb2d7c37c263..d1c9263511b0 100644 --- a/drivers/media/rc/ir-mce_kbd-decoder.c +++ b/drivers/media/rc/ir-mce_kbd-decoder.c @@ -219,6 +219,7 @@ static int ir_mce_kbd_decode(struct rc_dev *dev, struct ir_raw_event ev) struct mce_kbd_dec *data = &dev->raw->mce_kbd; u32 scancode; unsigned long delay; + unsigned long flags; struct lirc_scancode lsc = {}; if (!is_timing_event(ev)) { @@ -319,7 +320,7 @@ static int ir_mce_kbd_decode(struct rc_dev *dev, struct ir_raw_event ev) scancode = data->body & 0xffffff; dev_dbg(&dev->dev, "keyboard data 0x%08x\n", data->body); - spin_lock(&data->keylock); + spin_lock_irqsave(&data->keylock, flags); if (scancode) { delay = usecs_to_jiffies(dev->timeout) + msecs_to_jiffies(100); @@ -329,7 +330,7 @@ static int ir_mce_kbd_decode(struct rc_dev *dev, struct ir_raw_event ev) } /* Pass data to keyboard buffer parser */ ir_mce_kbd_process_keyboard_data(dev, scancode); - spin_unlock(&data->keylock); + spin_unlock_irqrestore(&data->keylock, flags); lsc.rc_proto = RC_PROTO_MCIR2_KBD; break; case MCIR2_MOUSE_NBITS: -- 2.55.0