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 393DB54CF6F; Tue, 8 Sep 2026 15:54:18 +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=1788882861; cv=none; b=c0M6itWyfHyQ+8CcYwg4kn60rac2RX74YOwXNopbAbbGy5zHKyMwqNltbCisUvCDlKBt+7i/i48+7txY//BV3Kr0bcTFpRSxG01htjAf+IIO9bNSGRlO/TWYnnOTXqrTJmoL+GjwX3JS9Pfhi53+XnE7h9BWI6B2MirggoL9PIw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788882861; c=relaxed/simple; bh=Za8UtDCRpcoLldjKGS5+rPnf9qprec85BjwFh0wyNAA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=l94iJCrNhc+5RWxkoFCvHHBN1fwj07Ds4FkAOpJ3BbBadaa6N09ubU1+Jj49xGmFkUE7mzcUFXy0j8jgYXo6FRxxlUNqm4ac4JVdHLjUMgHlGm9GKweyGSOAfZ6/gESez5Ql+Z4X2mb/o0Lx/oT6rEgVXAc97ET4ERooU+Fg36k= 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=dlzq+Hc1; dkim=pass (2048-bit key) header.d=mess.org header.i=@mess.org header.b=CXnIK05f; 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="dlzq+Hc1"; dkim=pass (2048-bit key) header.d=mess.org header.i=@mess.org header.b="CXnIK05f" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=mess.org; s=2020; t=1788882851; bh=Za8UtDCRpcoLldjKGS5+rPnf9qprec85BjwFh0wyNAA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dlzq+Hc13p51ZjGjRlBlOhtvN8/JrRHvmkfm95RmrI+bfkiQ8win/P5OzQDaqzHpX W1amkh/WKm10C05DEDHTAaoibUR4pU36aCH/ROgXWPVltnP/bGy9NGux7NProHEdJS 6HPvh5Q+zYx5Ifnbvi/KUK48fL75VbnVe4dc/IwpN6hPeleA4Y8OTbGrOQAUYHQuIM TsAatozbTLvbMiidC6ixzRuEn8Egh0r2+Zd1cH+3DMijZkiPAFdP5o6bx+24KGnX25 MgvoxHfUsZw0M9UUBwXOJqtpHbWlsU6cyqMwesgJWQL7xzx1jDFsPXHmh7zNkutLfW yyBoXZTS9/LFQ== Received: by extorris.mess.org (Postfix, from userid 1004) id B521D41450; Tue, 08 Sep 2026 16:54:11 +0100 (BST) X-Spam-Level: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=mess.org; s=2020; t=1788882850; bh=Za8UtDCRpcoLldjKGS5+rPnf9qprec85BjwFh0wyNAA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CXnIK05fGVkRaPwPSyRgAkkxv4SQNf3lqNGponzMK7rW1cwso4eI46m+ZJedtov4K x1gGHoygyYeZa2/EkEFGA7zmzOEoAfZmDhOBy8u+ENXVyP2+5rdq64vy3e1Wdtj1lW OiFnYnClaSu1xNEi1/qSpcf5CVQPmDGcaAztuwvhdp845mqT5eVFoDYRZItucksxhG ynL3Li+oT7pyQ7oL0OG6AqO5A04v8UFxr8R913RpL99izIIPyeUl89kfYk9VMqy6EG 6SemVbrIYs4P/PEy5BMX/E/cNlkuPy0Fl43SZ8LD1xx3rYlmg2GTZgnNdAjqR7zt8K gi2NwB4Y5QkCQ== Received: from maru.home (host86-150-50-53.range86-150.btcentralplus.com [86.150.50.53]) (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 807DA4144E; Tue, 08 Sep 2026 16:54:10 +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 v4 06/19] media: rc: mce_kbd: Fix inconsistent locking of keylock Date: Tue, 8 Sep 2026 16:51:54 +0100 Message-ID: <459aa19b705e1928f8591998e3a5fffa5b7f82b1.1788882189.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