[Makedumpfile Patch 3/6] x86_64: check physical address in PT_LOAD for none direct mapped regions

[Pratyush Anand]

A kcore PT_LOAD can have a section from vmalloc region. However,
physical address in that header would be invalid (-1) after a recent
kernel changes [0]. Therefore, check for valid physical address while
calculating page_offset or phys_offset.

[0] http://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/?h=next-20170206&id=c9d4e5d7b7fd6c74e134ca44df8a5386efbc561c

Signed-off-by: Pratyush Anand <panand at redhat.com>
---
 arch/x86_64.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86_64.c b/arch/x86_64.c
index 893cd516fc8b..e978a36f8878 100644
--- a/arch/x86_64.c
+++ b/arch/x86_64.c
@@ -41,7 +41,8 @@ get_page_offset_x86_64(void)
 	unsigned long long virt_start;
 
 	for (i = 0; get_pt_load(i, &phys_start, NULL, &virt_start, NULL); i++) {
-		if (virt_start < __START_KERNEL_map) {
+		if (virt_start < __START_KERNEL_map
+				&& phys_start != NOT_PADDR) {
 			info->page_offset = virt_start - phys_start;
 			return TRUE;
 		}
@@ -76,7 +77,8 @@ get_phys_base_x86_64(void)
 	}
 
 	for (i = 0; get_pt_load(i, &phys_start, NULL, &virt_start, NULL); i++) {
-		if (virt_start >= __START_KERNEL_map) {
+		if (virt_start >= __START_KERNEL_map
+				&& phys_start != NOT_PADDR) {
 
 			info->phys_base = phys_start -
 			    (virt_start & ~(__START_KERNEL_map));
-- 
2.9.3