Error while executing web part: System.StackOverflowException: Operation caused a stack overflow. at Microsoft.Xslt.NativeMethod.CheckForSufficientStack
I got the above error when using the OOTB search functionality in the page. OSSSearchResults.aspx
I noticed this because there was an error on the webpart
Unable to display this Web Part. To troubleshoot the problem, open this Web page in a Microsoft SharePoint Foundation-compatible HTML editor such as Microsoft SharePoint Designer. If the problem persists, contact your Web server administrator.
Correlation ID:41e19279-3151-4ac7-b12f-c396c73a7599
With the correlation id, I could find the problem in the log.