Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755149Ab3H1UYX (ORCPT ); Wed, 28 Aug 2013 16:24:23 -0400 Received: from mail-qc0-f172.google.com ([209.85.216.172]:46513 "EHLO mail-qc0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752978Ab3H1UYW (ORCPT ); Wed, 28 Aug 2013 16:24:22 -0400 MIME-Version: 1.0 In-Reply-To: <20130828202100.9134B3E0B6B@localhost> References: <5208C04A.5000303@gmail.com> <20130828202100.9134B3E0B6B@localhost> From: Grant Likely Date: Wed, 28 Aug 2013 21:24:00 +0100 X-Google-Sender-Auth: 6vrhQXbWC9B1rFcMUrgZEnHkoEA Message-ID: Subject: Re: [PATCH 1/1] of: fdt: fix memory initialization for expanded DT To: Wladislav Wiebe , Rob Herring , "devicetree@vger.kernel.org" Cc: Linux Kernel Mailing List Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2526 Lines: 56 On Wed, Aug 28, 2013 at 9:21 PM, Grant Likely wrote: > On Mon, 12 Aug 2013 13:00:26 +0200, Wladislav Wiebe wrote: >> Already existing property flags are filled wrong for properties created from >> initial FDT. This could cause problems if this DYNAMIC device-tree functions >> are used later, i.e. properties are attached/detached/replaced. Simply dumping >> flags from the running system show, that some initial static (not allocated via >> kzmalloc()) nodes are marked as dynamic. >> >> I putted some debug extensions to property_proc_show(..) : >> .. >> + if (OF_IS_DYNAMIC(pp)) >> + pr_err("DEBUG: xxx : OF_IS_DYNAMIC\n"); >> + if (OF_IS_DETACHED(pp)) >> + pr_err("DEBUG: xxx : OF_IS_DETACHED\n"); >> >> when you operate on the nodes (e.g.: ~$ cat /proc/device-tree/*some_node*) you >> will see that those flags are filled wrong, basically in most cases it will dump >> a DYNAMIC or DETACHED status, which is in not true. >> (BTW. this OF_IS_DETACHED is a own define for debug purposes which which just >> make a test_bit(OF_DETACHED, &x->_flags) >> >> If nodes are dynamic kernel is allowed to kfree() them. But it will crash >> attempting to do so on the nodes from FDT -- they are not allocated via >> kzmalloc(). >> >> Signed-off-by: Wladislav Wiebe >> --- >> drivers/of/fdt.c | 2 ++ >> 1 files changed, 2 insertions(+), 0 deletions(-) >> >> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c >> index 6bb7cf2..b10ba00 100644 >> --- a/drivers/of/fdt.c >> +++ b/drivers/of/fdt.c >> @@ -392,6 +392,8 @@ static void __unflatten_device_tree(struct boot_param_header *blob, >> mem = (unsigned long) >> dt_alloc(size + 4, __alignof__(struct device_node)); >> >> + memset((void *)mem, 0, size); >> + > > It seems to me that this would be a problem for any call to the early > allocation function; early_init_dt_alloc_memory_arch(). There is at > least one other call to the allocator via of_alias_scan(). I think this > patch is okay for now (I'll add the missing hunk), but it should be > revisited. Oops, I see that Rob has already applied it. I'll post the other change needed and post as a follow-on patch. Sorry for the noise. g. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/