From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e37.co.us.ibm.com (e37.co.us.ibm.com [32.97.110.158]) (using TLSv1 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 450F71A0478 for ; Wed, 28 Oct 2015 02:46:52 +1100 (AEDT) Received: from localhost by e37.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 27 Oct 2015 09:46:49 -0600 Received: from b03cxnp08027.gho.boulder.ibm.com (b03cxnp08027.gho.boulder.ibm.com [9.17.130.19]) by d03dlp02.boulder.ibm.com (Postfix) with ESMTP id DA96D3E40041 for ; Tue, 27 Oct 2015 09:46:47 -0600 (MDT) Received: from d03av04.boulder.ibm.com (d03av04.boulder.ibm.com [9.17.195.170]) by b03cxnp08027.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id t9RFklw69306420 for ; Tue, 27 Oct 2015 08:46:47 -0700 Received: from d03av04.boulder.ibm.com (loopback [127.0.0.1]) by d03av04.boulder.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id t9RFkl2V025948 for ; Tue, 27 Oct 2015 09:46:47 -0600 To: "linuxppc-dev@lists.ozlabs.org" Cc: Andy Shevchenko From: Nathan Fontenot Subject: [PATCH v2] powerpc/pseries: Correct string length in pseries_of_derive_parent() Message-ID: <562F9C67.3040207@linux.vnet.ibm.com> Date: Tue, 27 Oct 2015 10:46:47 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Commit a030e1e4bbd085bbcfd0a23f8d355fcd41f39bed make a change to use kstrndup() instead of kmalloc() + strlcpy() in the pseries_of_derive_parent() routine that introduces a subtle change in the parent path name generated. The kstrndup() routine will copy n characters followed by a terminating null, whereas strlcpy() will copy n-1 characters and add a terminating null. This slight difference results in having a parent path that includes the tailing '/' character, "/cpus/" vs. "/cpus". This then causes the subsequent call to of_find_node_by_path() to fail, and in the case of DLPAR add operations the DLPAR request fails. This patch decrements the pointer returned from kbasename() to point to the '/' character before the base name instead of the base name. This then adjusts the string length calculations to not include the trailing '/' in the parent path name. Signed-off-by: Nathan Fontenot --- Updates for v2: Decrement the pointer returned from kbasename() instead of subtracting 1 when calculating the string length. arch/powerpc/platforms/pseries/of_helpers.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/platforms/pseries/of_helpers.c b/arch/powerpc/platforms/pseries/of_helpers.c index 4417afe..2798933 100644 --- a/arch/powerpc/platforms/pseries/of_helpers.c +++ b/arch/powerpc/platforms/pseries/of_helpers.c @@ -17,13 +17,16 @@ struct device_node *pseries_of_derive_parent(const char *path) { struct device_node *parent; char *parent_path = "/"; - const char *tail = kbasename(path); + const char *tail; + + /* We do not want the trailing '/' character */ + tail = kbasename(path) - 1; /* reject if path is "/" */ if (!strcmp(path, "/")) return ERR_PTR(-EINVAL); - if (tail > path + 1) { + if (tail > path) { parent_path = kstrndup(path, tail - path, GFP_KERNEL); if (!parent_path) return ERR_PTR(-ENOMEM);