[PATCH] Fix ____call_usermodehelper errors being silently ignored

111dbe0c · Björn Steinbrink <[email protected]> · 2006-09-29 02:00:46 -07:00

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 <[email protected]>
Cc: Rusty Russell <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Commit: 111dbe0c8a21dffa473239861be47ebc87f593b3
Parents: 3e26a423

Changes

1 files changed · +11 −1

File	Status	Add	Del	Content
kernel/kmod.c	modified	+11	−1	View file

kernel/kmod.c

View file

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 @@ static int wait_for_helper(void *data)
 	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 @@ static int wait_for_helper(void *data)
 		 *
 		 * 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);