mapping perf sample events(PEBS) to kernel code

Hi, I am sampling Linux kernel using perf's perf_event_open functionality. The instruction pointers(IP) associated with PEBS events(PERF_RECORD_MISC_KERNEL), cannot be mapped back to kernel source code using addr2line while events generated from user-space (PERF_RECORD_MISC_USER) can be mapped back to application code. I am using appropriate vmlinux for kernel code attribution. Samples collected from existing perf tool can attribute to the kernel code. addr2line also works for those samples collected using perf tool. My question is why samples collected using perf_event_open fails to attribute to kernel code. Do I need to prepare the samples otherwise for the attribution? Thanks, Probir