[PATCH] Fix ____call_usermodehelper errors being silently ignored
If ____call_usermodehelper fails, we're not interested in the child
process' exit value, but the real error, so let's stop wait_for_helper from
overwriting it in that case.
Issue discovered by Benedikt Böhm while working on a Linux-VServer usermode
helper.
Signed-off-by: Björn Steinbrink <B.Steinbrink@gmx.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/kmod.c b/kernel/kmod.c
index 5c470c5..842f801 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -176,6 +176,8 @@
if (pid < 0) {
sub_info->retval = pid;
} else {
+ int ret;
+
/*
* Normally it is bogus to call wait4() from in-kernel because
* wait4() wants to write the exit code to a userspace address.
@@ -185,7 +187,15 @@
*
* Thus the __user pointer cast is valid here.
*/
- sys_wait4(pid, (int __user *) &sub_info->retval, 0, NULL);
+ sys_wait4(pid, (int __user *)&ret, 0, NULL);
+
+ /*
+ * If ret is 0, either ____call_usermodehelper failed and the
+ * real error code is already in sub_info->retval or
+ * sub_info->retval is 0 anyway, so don't mess with it then.
+ */
+ if (ret)
+ sub_info->retval = ret;
}
complete(sub_info->complete);
