From f755ecfb8cec7b19dff84295309f2afb24a5afd1 Mon Sep 17 00:00:00 2001 From: Nathan Fontenot Date: Tue, 27 Oct 2015 10:46:47 -0500 Subject: [PATCH] powerpc/pseries: Correct string length in pseries_of_derive_parent() 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 Reviewed-by: Andy Shevchenko Signed-off-by: Michael Ellerman --- 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 4417afef74d4..2798933c0e38 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); -- 2.34.1