提交 111dbe0c 编写于 作者: B Björn Steinbrink 提交者: Linus Torvalds

[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: NBjörn Steinbrink <B.Steinbrink@gmx.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
上级 3e26a423
......@@ -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);
......
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