From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752986AbbLFAOC (ORCPT ); Sat, 5 Dec 2015 19:14:02 -0500 Received: from bh-25.webhostbox.net ([208.91.199.152]:46334 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752104AbbLFAOA (ORCPT ); Sat, 5 Dec 2015 19:14:00 -0500 From: Guenter Roeck To: Rob Herring Cc: Frank Rowand , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Guenter Roeck , Pantelis Antoniou Subject: [PATCH] of/fdt: Add mutex protection for calls to __unflatten_device_tree() Date: Sat, 5 Dec 2015 16:13:53 -0800 Message-Id: <1449360833-27026-1-git-send-email-linux@roeck-us.net> X-Mailer: git-send-email 2.1.4 X-Authenticated_sender: guenter@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: guenter@roeck-us.net X-Authenticated-Sender: bh-25.webhostbox.net: guenter@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org __unflatten_device_tree() calls unflatten_dt_node(), which declares a static variable. It is therefore not reentrant. One of the callers of __unflatten_device_tree(), unflatten_device_tree(), is only called once during early initialization and does not need to be protected. The other caller, of_fdt_unflatten_tree(), can be called at any time, possibly multiple times in parallel. This can happen, for example, if multiple devicetree overlays have to be loaded and installed. Without this protection, errors such as the following may be seen. kernel: End of tree marker overwritten: e6a3a458 kernel: find_target_node: Failed to find target-indirect node at /fragment@0 kernel: __of_overlay_create: of_build_overlay_info() failed for tree@/ Add a mutex to of_fdt_unflatten_tree() to make the call reentrant. Cc: Pantelis Antoniou Signed-off-by: Guenter Roeck --- drivers/of/fdt.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c index d2430298a309..f13565d8b964 100644 --- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c @@ -13,6 +13,7 @@ #include #include #include +#include #include #include #include @@ -436,6 +437,8 @@ static void *kernel_tree_alloc(u64 size, u64 align) return kzalloc(size, GFP_KERNEL); } +static DEFINE_MUTEX(of_fdt_unflatten_mutex); + /** * of_fdt_unflatten_tree - create tree of device_nodes from flat blob * @@ -447,7 +450,9 @@ static void *kernel_tree_alloc(u64 size, u64 align) void of_fdt_unflatten_tree(const unsigned long *blob, struct device_node **mynodes) { + mutex_lock(&of_fdt_unflatten_mutex); __unflatten_device_tree(blob, mynodes, &kernel_tree_alloc); + mutex_unlock(&of_fdt_unflatten_mutex); } EXPORT_SYMBOL_GPL(of_fdt_unflatten_tree); -- 2.1.4