From patchwork Fri Dec 14 06:42:51 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Frank Rowand X-Patchwork-Id: 1013363 Return-Path: X-Original-To: incoming-dt@patchwork.ozlabs.org Delivered-To: patchwork-incoming-dt@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=devicetree-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="BfR4psKl"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 43GLbW5xR4z9sBn for ; Fri, 14 Dec 2018 17:43:19 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727239AbeLNGnL (ORCPT ); Fri, 14 Dec 2018 01:43:11 -0500 Received: from mail-pf1-f194.google.com ([209.85.210.194]:45665 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727179AbeLNGnK (ORCPT ); Fri, 14 Dec 2018 01:43:10 -0500 Received: by mail-pf1-f194.google.com with SMTP id g62so2331789pfd.12; Thu, 13 Dec 2018 22:43:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=Cf9GacyXSfcSYQD1hrpRVZxNJit6THuob2xtfEuPnDI=; b=BfR4psKlef8o1v7MrtDWgkZZzDExJYmy4mI4dQpM+NCUPR36QJKUy4unCEA57QnUUA Sps7DfOJ1jBmEfYhhCSRvMGVHvGYFb/NaYX9J5SEqeGEnOHBlNihiicX61pVD+T28TYs 4TNWbdVHqBicWWAIW/nkNhKqkqf1ldlMJ3WLyFWQB8MMWXMvSDs+reYLEKwrD0iVMTcq iSFJl0s30i76WyP/6mhp07Mw064q9uUVCjDzThKZd0Fh2H18oehZFVr+8s/f4SFm4zmT GWYzHI8o7MaYkIaXx7SA6AVW/SQ25KY8g9zbGr8eNhj7Onp5dm5QoOw031wSS8HFGDrj bdvQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=Cf9GacyXSfcSYQD1hrpRVZxNJit6THuob2xtfEuPnDI=; b=lkcXb/HpWzrzw4i5yM2F42hXtXhq/s/lnCxaeD8oPOnHCjPuSp8DuARPxKVkvERh4V 7YAYg2Ejj1mdZwg+L3TVkczxyrWP84y4y/NwSTPmGYxArO685pFz4l2LV/NF+QmOzK/A 4hYdjZ6EL5A8XT1pQdxvCFBkQLOwW6uES9ar2R8ejueFISGqFitBU/1hbjC0sDZLz2Be ctm8GrJ44NWDyp4JZQA4RyUJoB8FNPPpINsCcy6Eq+25co11NYl2+zCI4BV8yvDpwwyu auOUSC4cW5RYdefFD4EeqLQLsI8tl7aVLB4EBzB2/OO+2pd6z1bOpzY+0EFF46m1xtiz wPUw== X-Gm-Message-State: AA+aEWbY/QZwKn3a2JJ8LQaHyzoWShyp+FmRTJQCe4JbWKh7oT5ALit2 n8Pwhze3R4cO3YYqirJQneM= X-Google-Smtp-Source: AFSGD/Vg2CvhlVmp4b//gn5A/j1f42Ky3SwA3E9gurSpJOgfuPyLKwTNxjQsnapNqgIr3rq+9M+qEA== X-Received: by 2002:a63:9501:: with SMTP id p1mr1676451pgd.149.1544769790012; Thu, 13 Dec 2018 22:43:10 -0800 (PST) Received: from localhost.localdomain (c-24-6-192-50.hsd1.ca.comcast.net. [24.6.192.50]) by smtp.gmail.com with ESMTPSA id e16sm5132645pfn.46.2018.12.13.22.43.08 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 13 Dec 2018 22:43:09 -0800 (PST) From: frowand.list@gmail.com To: robh+dt@kernel.org, Michael Bringmann , linuxppc-dev@lists.ozlabs.org Cc: Michael Ellerman , Tyrel Datwyler , Thomas Falcon , Juliet Kim , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/2] of: __of_detach_node() - remove node from phandle cache Date: Thu, 13 Dec 2018 22:42:51 -0800 Message-Id: <1544769771-5468-3-git-send-email-frowand.list@gmail.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1544769771-5468-1-git-send-email-frowand.list@gmail.com> References: <1544769771-5468-1-git-send-email-frowand.list@gmail.com> Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org From: Frank Rowand Non-overlay dynamic devicetree node removal may leave the node in the phandle cache. Subsequent calls to of_find_node_by_phandle() will incorrectly find the stale entry. Remove the node from the cache. Add paranoia checks in of_find_node_by_phandle() as a second level of defense (do not return cached node if detached, do not add node to cache if detached). Reported-by: Michael Bringmann Signed-off-by: Frank Rowand --- drivers/of/base.c | 29 ++++++++++++++++++++++++++++- drivers/of/dynamic.c | 3 +++ drivers/of/of_private.h | 4 ++++ 3 files changed, 35 insertions(+), 1 deletion(-) diff --git a/drivers/of/base.c b/drivers/of/base.c index d599367cb92a..34a5125713c8 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -162,6 +162,27 @@ int of_free_phandle_cache(void) late_initcall_sync(of_free_phandle_cache); #endif +/* + * Caller must hold devtree_lock. + */ +void __of_free_phandle_cache_entry(phandle handle) +{ + phandle masked_handle; + + if (!handle) + return; + + masked_handle = handle & phandle_cache_mask; + + if (phandle_cache) { + if (phandle_cache[masked_handle] && + handle == phandle_cache[masked_handle]->phandle) { + of_node_put(phandle_cache[masked_handle]); + phandle_cache[masked_handle] = NULL; + } + } +} + void of_populate_phandle_cache(void) { unsigned long flags; @@ -1209,11 +1230,17 @@ struct device_node *of_find_node_by_phandle(phandle handle) if (phandle_cache[masked_handle] && handle == phandle_cache[masked_handle]->phandle) np = phandle_cache[masked_handle]; + if (np && of_node_check_flag(np, OF_DETACHED)) { + of_node_put(np); + phandle_cache[masked_handle] = NULL; + np = NULL; + } } if (!np) { for_each_of_allnodes(np) - if (np->phandle == handle) { + if (np->phandle == handle && + !of_node_check_flag(np, OF_DETACHED)) { if (phandle_cache) { /* will put when removed from cache */ of_node_get(np); diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c index f4f8ed9b5454..ecea92f68c87 100644 --- a/drivers/of/dynamic.c +++ b/drivers/of/dynamic.c @@ -268,6 +268,9 @@ void __of_detach_node(struct device_node *np) } of_node_set_flag(np, OF_DETACHED); + + /* race with of_find_node_by_phandle() prevented by devtree_lock */ + __of_free_phandle_cache_entry(np->phandle); } /** diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h index 5d1567025358..24786818e32e 100644 --- a/drivers/of/of_private.h +++ b/drivers/of/of_private.h @@ -84,6 +84,10 @@ static inline void __of_detach_node_sysfs(struct device_node *np) {} int of_resolve_phandles(struct device_node *tree); #endif +#if defined(CONFIG_OF_DYNAMIC) +void __of_free_phandle_cache_entry(phandle handle); +#endif + #if defined(CONFIG_OF_OVERLAY) void of_overlay_mutex_lock(void); void of_overlay_mutex_unlock(void);