Re: [RFC 0/4] perf tool: Fix non-".text" symbol resolution for kernel modules

[Ravi Bangoria]

Hi all,

On 10-Jan-23 11:28 AM, Ravi Bangoria wrote:
> Kernel module elf contains executable code in non-".text" sections as
> well, for ex: ".noinstr.text". Plus, kernel module's memory layout
> differs from it's binary layout because .ko elf does not contain
> program header table.
> 
> Perf tries to solve it by creating special maps for allocated (SHF_ALLOC)
> elf sections, but perf uses elf addresses for map address range and thus
> these special maps remains unused because no real ip falls into their
> address range.
> 
> Solve this by preparing section specific special maps using addresses
> provided by sysfs /sys/module/.../sections/. Also save these details in
> PERF_RECORD_KMOD_SEC_MAP format in perf.data which can be consumed at
> perf-report time.

Do you guys feel this is worth to fix and I shall continue? Or --kcore /
--kallsyms workarounds are sufficient?

Thanks,
Ravi