From: Björn Steinbrink Date: Fri, 29 Sep 2006 09:00:46 +0000 (-0700) Subject: [PATCH] Fix ____call_usermodehelper errors being silently ignored X-Git-Tag: v2.6.19-rc1~728 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=111dbe0c8a21dffa473239861be47ebc87f593b3;p=linux-2.6 [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 Cc: Rusty Russell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/kernel/kmod.c b/kernel/kmod.c index 5c470c57fb..842f8015d7 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);