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 B986815198D; Wed, 5 Feb 2025 14:10:19 +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=1738764619; cv=none; b=QoZafyZ1bnwZp4hnScgMbMPBLTQu3cTfOxR22sIIgjnh++9IgfzE2MqA0ks8o2yn143YCUKl3XnFejT7BytZnVcS7va/F7e9BuiyvFeZWT3r9S6pcz2rdIFrZk31XnxzgJFfIBDvCnnDwHMFogfg/+nswY2XK4m752AgAp8huvM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738764619; c=relaxed/simple; bh=j9+JeRMDM/1uDOMxwseuGh/JHM/MB+n1paaVgplq7TI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HnSwzgP1wHhoOoguRd3FXtfZg6y8TnUAqygD62QzY4YbZmhOKhJZZp6FyNangWjUI4ypLjc7ZyVuuPCe//lFBH1cO/VqZOdSGv/caSpJJjlg3vw+hLc5cVYBfmSlMfiLG0jVSrOqyrIgObT1dsIP0K6cils3aTShAwNP/ISjKfQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=hJnqXRor; 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="hJnqXRor" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 38355C4CEDD; Wed, 5 Feb 2025 14:10:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1738764619; bh=j9+JeRMDM/1uDOMxwseuGh/JHM/MB+n1paaVgplq7TI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hJnqXRorhFrx/QeysxT6k+E81PyWt6dKrEESSnqGG3pYZRSd0ZHx+NKjwpVSaSJee kgLERtauCY4XNvVoqeALp3+L+on9pTwEvPHEEjCx82gHuXG1l6k9tCxgE9d6hfqCFu gPsilhZ4sUCKnj3xQr91PKRcleMKQN287VzEpnrQ= 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 6.12 143/590] mfd: syscon: Fix race in device_node_get_regmap() Date: Wed, 5 Feb 2025 14:38:18 +0100 Message-ID: <20250205134500.741167366@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250205134455.220373560@linuxfoundation.org> References: <20250205134455.220373560@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 6.12-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 2ce15f60eb107..729e79e1be49f 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); @@ -144,9 +147,7 @@ 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); @@ -167,7 +168,7 @@ 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) { @@ -175,11 +176,11 @@ 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); @@ -210,7 +211,7 @@ 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) { @@ -223,12 +224,12 @@ 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