initramfs: add write error checks

On a system with low memory extracting the initramfs may fail.  If this
happens the user gets "Failed to execute /init" instead of an initramfs
error.

Check return value of sys_write and call error() when the write was
incomplete or failed.

Signed-off-by: David Engraf <david.engraf@sysgo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/init/initramfs.c b/init/initramfs.c
index a7566031242e..bece48c3461e 100644
--- a/init/initramfs.c
+++ b/init/initramfs.c
@@ -369,7 +369,8 @@ static int __init do_name(void)
 static int __init do_copy(void)
 {
         if (count >= body_len) {
-                xwrite(wfd, victim, body_len);
+                if (xwrite(wfd, victim, body_len) != body_len)
+                        error("write error");
                 sys_close(wfd);
                 do_utime(vcollected, mtime);
                 kfree(vcollected);
@@ -377,7 +378,8 @@ static int __init do_copy(void)
                 state = SkipIt;
                 return 0;
         } else {
-                xwrite(wfd, victim, count);
+                if (xwrite(wfd, victim, count) != count)
+                        error("write error");
                 body_len -= count;
                 eat(count);
                 return 1;