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 7E2214C77A5; Wed, 22 Jul 2026 10:23:45 +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=1784715827; cv=none; b=G7NKslTL8JzjWjJ0V3uKklWCM1GSrenVI/0FVibLdBqw2E/3V51Zb7bYUIm21uSkbMEXfQnPSZ7/9bWTHO6+/8wfHHc5z+MynIlTOGITQtJbUwMvFnAxNBDTaUKSKy9edrhHI43MN9s7Vc2v4w008Y6S7JjTHbkrGz34ubjpTIg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784715827; c=relaxed/simple; bh=4CpmGGiYX0XDIWEvB5BLJQQ+5BYs2QbT7UxoeJF38kY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=SGB2B07A8Dk4GGnz76rds11gU0gnjqB/zc2fX6XcoOgi73Sqcu/SUtJsZtpQUGVArUEmSoFCI7Fe8M4ILiEnQpkaN+/6gK1LDXoKTKj92jyIYrNlJcMw5hv7/mqTznhD4dXlsyAZmn/fnnbK2vY9Qzy7v+Tdw/apXSz+7BJQvs8= 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=S6lho7Cz; dkim=pass (2048-bit key) header.d=mess.org header.i=@mess.org header.b=S6lho7Cz; 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="S6lho7Cz"; dkim=pass (2048-bit key) header.d=mess.org header.i=@mess.org header.b="S6lho7Cz" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=mess.org; s=2020; t=1784715823; bh=4CpmGGiYX0XDIWEvB5BLJQQ+5BYs2QbT7UxoeJF38kY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=S6lho7Czl+rXsDUPPExvYeDZ0iwlJWgcS8FchgF/ciRpp8TbvwbwmtCd8C0vrzN1j jNYoa8SCj5p2piaA755k7O8ht+ce0ZTElAOlryIFtmWVq8S2HRYQzVd3x/IrctGnIM RO3HGv0l6w3v0rQU/F4ZvoPSk/RR2pATn9J1aycPA1rR+RvRRF1URHI6NuNhWD9HWM vtU1LX3sYPgDrdiF/WiBK5o74yU+eXA7vR7RS1QInu+paXTjvbyXrm8tzmNsQuZLhA c+UlfQ5/pEk6vpDMVTQL4G2lzZsH5hZEfhsabK+rnBXnCBvAqK5dmus+SO+96PkrXb FJFYX0+dnaaMQ== Received: by extorris.mess.org (Postfix, from userid 1004) id F3B0D42540; Wed, 22 Jul 2026 11:23:43 +0100 (BST) X-Spam-Level: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=mess.org; s=2020; t=1784715823; bh=4CpmGGiYX0XDIWEvB5BLJQQ+5BYs2QbT7UxoeJF38kY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=S6lho7Czl+rXsDUPPExvYeDZ0iwlJWgcS8FchgF/ciRpp8TbvwbwmtCd8C0vrzN1j jNYoa8SCj5p2piaA755k7O8ht+ce0ZTElAOlryIFtmWVq8S2HRYQzVd3x/IrctGnIM RO3HGv0l6w3v0rQU/F4ZvoPSk/RR2pATn9J1aycPA1rR+RvRRF1URHI6NuNhWD9HWM vtU1LX3sYPgDrdiF/WiBK5o74yU+eXA7vR7RS1QInu+paXTjvbyXrm8tzmNsQuZLhA c+UlfQ5/pEk6vpDMVTQL4G2lzZsH5hZEfhsabK+rnBXnCBvAqK5dmus+SO+96PkrXb FJFYX0+dnaaMQ== Received: from maru.local (unknown [62.232.99.130]) (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 E27DA42528; Wed, 22 Jul 2026 11:23:42 +0100 (BST) From: Sean Young To: linux-media@vger.kernel.org, Sean Young , Mauro Carvalho Chehab Cc: linux-kernel@vger.kernel.org Subject: [PATCH v3 13/13] media: rc: Fix race condition during rc_register_device() Date: Wed, 22 Jul 2026 11:23:25 +0100 Message-ID: <3605fbe4b95f8c3f92849b67a7b8b79b28dad736.1784715737.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 The correct sequence for rc core is so: rc_allocation_device() /* * setup hardware and now calls to ir_raw_event_store etc are * permitted, as well as rc_keydown. There is no rc device in sysfs * or lirc chardev. */ rc_register_device() /* * After rc_register_device(), the rc device can be used now from lirc * chardev, sysfs and IR is now decoded and reported. */ rc_unregister_device() /* * User space can no longer access /dev/lirc or the rc sysfs * attributes. They will get -ENODEV if they still have a file * descriptor open. * Calls to ir_raw_event_handle() etc or rc_keydown() are permitted * but they must stop before the call to rc_free_device(), so * this is the time to stop the hardware. */ rc_free_device() This means that during rc_register_device(), we can get calls to ir_raw_event_{store,handle,overflow,store_with_filter}. Ensure this is done race-free. Signed-off-by: Sean Young --- drivers/media/rc/rc-ir-raw.c | 20 +------------------- drivers/media/rc/rc-main.c | 18 +++++++++++------- 2 files changed, 12 insertions(+), 26 deletions(-) diff --git a/drivers/media/rc/rc-ir-raw.c b/drivers/media/rc/rc-ir-raw.c index 26962b500b0c..963562f03770 100644 --- a/drivers/media/rc/rc-ir-raw.c +++ b/drivers/media/rc/rc-ir-raw.c @@ -71,9 +71,6 @@ static int ir_raw_event_thread(void *data) */ int ir_raw_event_store(struct rc_dev *dev, struct ir_raw_event *ev) { - if (!dev->raw) - return -EINVAL; - dev_dbg(&dev->dev, "sample: (%05dus %s)\n", ev->duration, TO_STR(ev->pulse)); @@ -102,9 +99,6 @@ int ir_raw_event_store_edge(struct rc_dev *dev, bool pulse) ktime_t now; struct ir_raw_event ev = {}; - if (!dev->raw) - return -EINVAL; - now = ktime_get(); ev.duration = ktime_to_us(ktime_sub(now, dev->raw->last_event)); ev.pulse = !pulse; @@ -129,9 +123,6 @@ int ir_raw_event_store_with_timeout(struct rc_dev *dev, struct ir_raw_event *ev) ktime_t now; int rc = 0; - if (!dev->raw) - return -EINVAL; - now = ktime_get(); spin_lock(&dev->raw->edge_spinlock); @@ -166,9 +157,6 @@ EXPORT_SYMBOL_GPL(ir_raw_event_store_with_timeout); */ int ir_raw_event_store_with_filter(struct rc_dev *dev, struct ir_raw_event *ev) { - if (!dev->raw) - return -EINVAL; - /* Ignore spaces in idle mode */ if (dev->idle && !ev->pulse) return 0; @@ -200,9 +188,6 @@ EXPORT_SYMBOL_GPL(ir_raw_event_store_with_filter); */ void ir_raw_event_set_idle(struct rc_dev *dev, bool idle) { - if (!dev->raw) - return; - dev_dbg(&dev->dev, "%s idle mode\n", idle ? "enter" : "leave"); if (idle) { @@ -226,7 +211,7 @@ EXPORT_SYMBOL_GPL(ir_raw_event_set_idle); */ void ir_raw_event_handle(struct rc_dev *dev) { - if (!dev->raw || !dev->raw->thread) + if (!dev->raw->thread) return; wake_up_process(dev->raw->thread); @@ -612,9 +597,6 @@ EXPORT_SYMBOL(ir_raw_encode_carrier); */ int ir_raw_event_prepare(struct rc_dev *dev) { - if (!dev) - return -EINVAL; - dev->raw = kzalloc_obj(*dev->raw); if (!dev->raw) return -ENOMEM; diff --git a/drivers/media/rc/rc-main.c b/drivers/media/rc/rc-main.c index dda3479ea3ad..365f3d056a06 100644 --- a/drivers/media/rc/rc-main.c +++ b/drivers/media/rc/rc-main.c @@ -1701,14 +1701,24 @@ static const struct device_type rc_dev_type = { struct rc_dev *rc_allocate_device(enum rc_driver_type type) { struct rc_dev *dev; + int ret; dev = kzalloc_obj(*dev); if (!dev) return NULL; + if (type == RC_DRIVER_IR_RAW) { + ret = ir_raw_event_prepare(dev); + if (ret < 0) { + kfree(dev); + return NULL; + } + } + if (type != RC_DRIVER_IR_RAW_TX) { dev->input_dev = input_allocate_device(); if (!dev->input_dev) { + ir_raw_event_free(dev); kfree(dev); return NULL; } @@ -1724,6 +1734,7 @@ struct rc_dev *rc_allocate_device(enum rc_driver_type type) spin_lock_init(&dev->rc_map.lock); spin_lock_init(&dev->keylock); } + mutex_init(&dev->lock); dev->dev.type = &rc_dev_type; @@ -1917,12 +1928,6 @@ int rc_register_device(struct rc_dev *dev) dev->sysfs_groups[attr++] = &rc_dev_wakeup_filter_attr_grp; dev->sysfs_groups[attr++] = NULL; - if (dev->driver_type == RC_DRIVER_IR_RAW) { - rc = ir_raw_event_prepare(dev); - if (rc < 0) - goto out_minor; - } - if (dev->driver_type != RC_DRIVER_IR_RAW_TX) { rc = rc_prepare_rx_device(dev); if (rc) @@ -1980,7 +1985,6 @@ int rc_register_device(struct rc_dev *dev) ir_free_table(&dev->rc_map); out_raw: ir_raw_event_free(dev); -out_minor: ida_free(&rc_ida, minor); return rc; } -- 2.55.0