From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 18D0413C3F6; Wed, 5 Feb 2025 14:21:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738765299; cv=none; b=a9Zgd/cyAzZsudm0cNdEftT+3ZJVm9o7vp8XusfG9CySJ8yVAr4+5RUsOK+LZ71l1Sto1V6FJOZKB/3vFz3t48b0BETvA+Jd6J240lRXVey7rxz47laV8fDWRFmqta0I3pJGyFgTf/uBgd/tZjlLUmv5ZWHVZcelgPBfRASwFTo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738765299; c=relaxed/simple; bh=JRQJCi0r+G9T3B9J+VGYjJhZ7rPeKedrxmpfkV4H7Lg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OUSbhnaQcO38tidl5zYwfGA5HaORZxLQ4jzJm7vKjQR29U35BIgCGSbCiiDKcIHklXCHP8mx/cmg+mClLX+4UZ38D0PzKJo5yqReAbt5WeYgL8UjCih2v3sdpXG6QQKHnBc46nIICgRHdbl7ZwpyRUjygAIDHMxVEITPaFx5n2U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=qVzDrdbO; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="qVzDrdbO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 13D4BC4CED1; Wed, 5 Feb 2025 14:21:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1738765298; bh=JRQJCi0r+G9T3B9J+VGYjJhZ7rPeKedrxmpfkV4H7Lg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qVzDrdbOlHJP5tui3S25gXZW2FWb5J9AngEnV2nHHekkwI+ozz5umo1UcFwd+oaUC 5LdgV7ovAYy/X5LhZWz28+BFPsNDR/6bAKDjWnEK35O9IClkx/gEwfl3KkTk3OVZ+w daIol+lMFoSoHuXP8knJJ1fnzfrNt3bO5jzDc+mQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Rob Herring (Arm)" , Krzysztof Kozlowski , Will McVicker , Pankaj Dubey , Lee Jones , Sasha Levin Subject: [PATCH 6.13 149/623] mfd: syscon: Fix race in device_node_get_regmap() Date: Wed, 5 Feb 2025 14:38:11 +0100 Message-ID: <20250205134501.935750459@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250205134456.221272033@linuxfoundation.org> References: <20250205134456.221272033@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.13-stable review patch. If anyone has any objections, please let me know. ------------------ From: Rob Herring (Arm) [ Upstream commit 805f7aaf7fee14a57b56af01d270edf6c10765e8 ] It is possible for multiple, simultaneous callers calling device_node_get_regmap() with the same node to fail to find an entry in the syscon_list. There is a period of time while the first caller is calling of_syscon_register() that subsequent callers also fail to find an entry in the syscon_list and then call of_syscon_register() a second time. Fix this by keeping the lock held until after of_syscon_register() completes and adds the node to syscon_list. Convert the spinlock to a mutex as many of the functions called in of_syscon_register() such as kzalloc() and of_clk_get() may sleep. Fixes: bdb0066df96e ("mfd: syscon: Decouple syscon interface from platform devices") Signed-off-by: Rob Herring (Arm) Reviewed-by: Krzysztof Kozlowski Tested-by: Krzysztof Kozlowski Tested-by: Will McVicker Tested-by: Pankaj Dubey Reviewed-by: Pankaj Dubey Link: https://lore.kernel.org/r/20241217-syscon-fixes-v2-1-4f56d750541d@kernel.org Signed-off-by: Lee Jones Signed-off-by: Sasha Levin --- drivers/mfd/syscon.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-) diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c index 3e1d699ba9340..72f20de9652da 100644 --- a/drivers/mfd/syscon.c +++ b/drivers/mfd/syscon.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include #include @@ -27,7 +28,7 @@ static struct platform_driver syscon_driver; -static DEFINE_SPINLOCK(syscon_list_slock); +static DEFINE_MUTEX(syscon_list_lock); static LIST_HEAD(syscon_list); struct syscon { @@ -54,6 +55,8 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_res) struct resource res; struct reset_control *reset; + WARN_ON(!mutex_is_locked(&syscon_list_lock)); + struct syscon *syscon __free(kfree) = kzalloc(sizeof(*syscon), GFP_KERNEL); if (!syscon) return ERR_PTR(-ENOMEM); @@ -146,9 +149,7 @@ static struct syscon *of_syscon_register(struct device_node *np, bool check_res) syscon->regmap = regmap; syscon->np = np; - spin_lock(&syscon_list_slock); list_add_tail(&syscon->list, &syscon_list); - spin_unlock(&syscon_list_slock); return_ptr(syscon); @@ -169,7 +170,7 @@ static struct regmap *device_node_get_regmap(struct device_node *np, { struct syscon *entry, *syscon = NULL; - spin_lock(&syscon_list_slock); + mutex_lock(&syscon_list_lock); list_for_each_entry(entry, &syscon_list, list) if (entry->np == np) { @@ -177,11 +178,11 @@ static struct regmap *device_node_get_regmap(struct device_node *np, break; } - spin_unlock(&syscon_list_slock); - if (!syscon) syscon = of_syscon_register(np, check_res); + mutex_unlock(&syscon_list_lock); + if (IS_ERR(syscon)) return ERR_CAST(syscon); @@ -212,7 +213,7 @@ int of_syscon_register_regmap(struct device_node *np, struct regmap *regmap) return -ENOMEM; /* check if syscon entry already exists */ - spin_lock(&syscon_list_slock); + mutex_lock(&syscon_list_lock); list_for_each_entry(entry, &syscon_list, list) if (entry->np == np) { @@ -225,12 +226,12 @@ int of_syscon_register_regmap(struct device_node *np, struct regmap *regmap) /* register the regmap in syscon list */ list_add_tail(&syscon->list, &syscon_list); - spin_unlock(&syscon_list_slock); + mutex_unlock(&syscon_list_lock); return 0; err_unlock: - spin_unlock(&syscon_list_slock); + mutex_unlock(&syscon_list_lock); kfree(syscon); return ret; } -- 2.39.5