[PATCH] kexec: fix mmap return code handling

[Michael Holzheu]

Hi Simon,

I made a mistake in my mmap patch, sorry for that!

When mmap fails, MAP_FAILED (that is, (void *) -1) is returned. Currently
we assume that NULL is returned. Fix this and add the MAP_FAILED check.

Fixes: 95741713e790 ("kexec/s390x: use mmap instead of read for slurp_file")
Signed-off-by: Michael Holzheu <holzheu at linux.vnet.ibm.com>
---
 kexec/kexec.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kexec/kexec.c b/kexec/kexec.c
index cf6e03d..02285fb 100644
--- a/kexec/kexec.c
+++ b/kexec/kexec.c
@@ -568,6 +568,8 @@ static char *slurp_file_generic(const char *filename, off_t *r_size,
 		if (use_mmap) {
 			buf = mmap(NULL, size, PROT_READ|PROT_WRITE,
 				   MAP_PRIVATE, fd, 0);
+			if (buf == MAP_FAILED)
+				buf = NULL;
 			nread = size;
 		} else {
 			buf = slurp_fd(fd, filename, size, &nread);
-- 
2.3.9