powerpc/pseries: Validate PFN in pseries_remove_lmb()

The pfn of the memory to be removed should be validated prior to
attempting to remove the memory.  In cases where the probe of a
memory section fails during hotplug add, the pfn for the lmb may
not be valid.

Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Nathan Fontenot <nfont@austin.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
index 140d02a5232a..a623ad256e9e 100644
--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
@@ -22,6 +22,12 @@ static int pseries_remove_lmb(unsigned long base, unsigned int lmb_size)
         int ret;
 
         start_pfn = base >> PAGE_SHIFT;
+
+        if (!pfn_valid(start_pfn)) {
+                lmb_remove(base, lmb_size);
+                return 0;
+        }
+
         zone = page_zone(pfn_to_page(start_pfn));
 
         /*