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 6651E47A882; Tue, 15 Sep 2026 08:33:07 +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=1789461189; cv=none; b=XWGekEN9QUnvqVHyr1XUUxmS9G2s1t5M8qz0xPYDOVD60vzRsl3S4e16g3TC1Y6C8Ac5BS3WPuOd9ja2d3sYXjXFtb2f8LOaOTyOvszkXYYnb2zQwD/LlFX70V7nlLxIaa0Rnq/qCHjAWPXILIqQt9qY+R73kdE/td26PXtLqFE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789461189; c=relaxed/simple; bh=Za8UtDCRpcoLldjKGS5+rPnf9qprec85BjwFh0wyNAA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=sA8JJxEu/H2fgrRhV58kTeKfvQho6F3ylzdJu/dVKxDVDt7DudGMwgxvhZIYZDaa2wmTEgOXMhrWwf/VDWHGWNY4wabWrG2PE3gQoI575QFW4EMiXeaMrME7CE3bxM0TEn58t6/0v75iGFBG5V0sX28RFz5fwn5qn8Sn948gbgs= 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=I0mvEOmB; dkim=pass (2048-bit key) header.d=mess.org header.i=@mess.org header.b=pYcarSRL; 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="I0mvEOmB"; dkim=pass (2048-bit key) header.d=mess.org header.i=@mess.org header.b="pYcarSRL" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=mess.org; s=2020; t=1789461186; bh=Za8UtDCRpcoLldjKGS5+rPnf9qprec85BjwFh0wyNAA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=I0mvEOmB7mGobLOKOQCnqhwjwKDXVhyrdyiN7/CRe/pKSVpIEC4Y/JBFV/Bt2LqlG gObVAusXm76Mjlb69wGiOREpQMo5htg5KyRcdbk3qS8obv2rQjBJpyzlcMWmP9dcfU wCKCsJT3nlbY/IPX2afYwX32e9bsEyzCOjcKOI/OYWbhQ6kAvUr+kqZ+yfIAxhu04m U4UbQVhNHROUJIaSIpgNEEAqI2kUD1R8n3HVqPxII8irHNdY6WSnwa86YHA/gxvEvK ZtGQEYfKKo7QsD3T3C+MH/k+lOao1SWjgvuDsU2hNf1INZOIGXP3ONb1H0OZOoYW1P Dktct+yGSDEcw== Received: by extorris.mess.org (Postfix, from userid 1004) id 0AD0440BA7; Tue, 15 Sep 2026 09:33:06 +0100 (BST) X-Spam-Level: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=mess.org; s=2020; t=1789461185; bh=Za8UtDCRpcoLldjKGS5+rPnf9qprec85BjwFh0wyNAA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pYcarSRLvr3C7I9mNCESy8WYR/lLoBTUDFXzAsqFYr8+0T/IA0P9A8SriV1Hs4bqE siUGWxzxq4i/UsT91DFLdpbjp7EMfS4kzXD0VVwQjjxuAhyDmOL3HLD7nFBKaLwWpG ee4hqnyzvnoaMXFvFFAJokQr6rwiEexKtOjOqu+p67feQe/J1rCMgPLIhVWfVG2PRB W8OEi3hxClsCZBC5vz3IKqFaGkKf5mGDPM2gqwnc1Mxq+jMg/78nALa8cppemBdMCj Ir1IzA5RplvR3BW51+fhqjI9nB1pZs2s23If4M3vdASLFMV9JTnq7nCnF/gvOV4LP4 ftP4gEkmC3h0A== Received: from maru.home (host81-158-254-226.range81-158.btcentralplus.com [81.158.254.226]) (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 438D440B71; Tue, 15 Sep 2026 09:33:05 +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 v5 07/20] media: rc: mce_kbd: Fix inconsistent locking of keylock Date: Tue, 15 Sep 2026 09:32:17 +0100 Message-ID: <4f56b84535b67c38bdf1dc7858ef60197c059b97.1789460680.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