Align memsz before locate hole fix

o This patch fixes a problem reported on the platform where memory end is not
  page aligned. There kexec gives an error "Invalid memory segment". The
  problem has been identified by Aaron Klingaman.

o Problem occurs when add_buffer() tries to add a buffer of size memsz which
  is not integral multiple of page size. Add buffer calls locate_hole() which
  returns successfully. Later add_buffer() calls add_segment() which in turn
  makes all segment sizes page aligned and then verifies if memory range is
  valid or not. This creates a problem if memory end is not page aligned and
  a buffer has been allocated on memory end boundary. Because memsz has been
  made page aligned after calling locate_buffer(), it might have crossed
  valid memory locations.

o Problem is fixed by page aligning the memsz in add_buffer() before calling
  locate_hole().

Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Maneesh Soni <maneesh@in.ibm.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/kexec/kexec.c b/kexec/kexec.c
index fd66e15..d6cca88 100644
--- a/kexec/kexec.c
+++ b/kexec/kexec.c
@@ -324,12 +324,17 @@ unsigned long add_buffer(struct kexec_info *info,
 {
 	unsigned long base;
 	int result;
+	int pagesize;
 
 	result = sort_segments(info);
 	if (result < 0) {
 		die("sort_segments failed\n");
 	}
 
+	/* Round memsz up to a multiple of pagesize */
+	pagesize = getpagesize();
+	memsz = (memsz + (pagesize - 1)) & ~(pagesize - 1);
+
 	base = locate_hole(info, memsz, buf_align, buf_min, buf_max, buf_end);
 	if (base == ULONG_MAX) {
 		die("locate_hole failed\n");