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Commit 111dbe0c authored by Björn Steinbrink's avatar Björn Steinbrink Committed by Linus Torvalds
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[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: default avatarBjörn Steinbrink <B.Steinbrink@gmx.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 3e26a423

kernel/kmod.c

+11 −1
Original line number Diff line number Diff line
@@ -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);