Configured search on SharePoint Foundation 2010, but only some user can get the search results, the others not! Users have different privileges, so it's not the case when search works only with farm admins.
Inspecting SharePoint log, I found this
AuthzInitializeContextFromSid failed with ERROR_ACCESS_DENIED. This error indicates that the account under which this process is executing may not have read access to the tokenGroupsGlobalAndUniversal attribute on the querying user's Active Directory object. Query results which require non-Claims Windows authorization will not be returned to this querying user.
After googled about the problem, I found this post http://blogs.msdn.com/b/russmax/archive/2010/01/20/why-the-tokengroupsglobalanduniversal-tggau-attribute-matters-in-sharepoint-2010.aspx
There is a group in AD called Pre-Windows 2000 Compatibility Access, I added search service account to this group and search started working properly