From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755536AbbKRKqn (ORCPT ); Wed, 18 Nov 2015 05:46:43 -0500 Received: from ozlabs.org ([103.22.144.67]:57232 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751843AbbKRKql (ORCPT ); Wed, 18 Nov 2015 05:46:41 -0500 From: Michael Ellerman To: robh+dt@kernel.org Cc: devicetree@vger.kernel.org, , , mitchelh@codeaurora.org, frowand.list@gmail.com, grant.likely@linaro.org Subject: [PATCH] of: Fix comparison of reserved memory regions Date: Wed, 18 Nov 2015 21:46:38 +1100 Message-Id: <1447843598-9355-1-git-send-email-mpe@ellerman.id.au> X-Mailer: git-send-email 2.5.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In order to check for overlapping reserved memory regions, we first need to sort the array of memory regions. This is implemented using sort(), and a custom comparison function __rmem_cmp(). Unfortunatley __rmem_cmp() doesn't work in all cases. Because the two base values are phys_addr_t, they may be u64 on some platforms, in which case subtracting one from the other and then (implicitly) casting to int does not give us the -ve/0/+ve value we need. This leads to incorrect reports about overlaps, eg: ibm,slw-image@1ffe600000 (0x0000001ffe600000--0x0000001ffe700000) overlaps with ibm,firmware-allocs-memory@1000000000 (0x0000001000000000--0x0000001000dc0200) Fix it by just doing the standard double if and return 0 logic. Fixes: ae1add247bf8 ("of: Check for overlap in reserved memory regions") Signed-off-by: Michael Ellerman --- drivers/of/of_reserved_mem.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c index be77e75c587d..1a3556a9e9ea 100644 --- a/drivers/of/of_reserved_mem.c +++ b/drivers/of/of_reserved_mem.c @@ -206,7 +206,13 @@ static int __init __rmem_cmp(const void *a, const void *b) { const struct reserved_mem *ra = a, *rb = b; - return ra->base - rb->base; + if (ra->base < rb->base) + return -1; + + if (ra->base > rb->base) + return 1; + + return 0; } static void __init __rmem_check_for_overlap(void) -- 2.5.0