valgrind asking for debuginfo libc6-dbg - valgrind

Question

I have gone through the answers related to this error. However, my question is once I have debuginfo of libc, what is the location that i should place this library, in order for valgrind to see it?
I have downloaded valgrind and cross compiled for my target environment.
I tried all different combinations below:
I placed libc in /lib and debuginfo in /lib/debug
renamed debuginfo to libc.debug
exported VALGRIND_LIB to include /lib, /lib/debug
Last but not least, below is the actual error:
==29946== Memcheck, a memory error detector
==29946== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==29946== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info
==29946== Command: /bin/my_prog
==29946==
valgrind: Fatal error at startup: a function redirection
valgrind: which is mandatory for this platform-tool combination
valgrind: cannot be set up. Details of the redirection are:
valgrind:
valgrind: A must-be-redirected function
valgrind: whose name matches the pattern: strcmp
valgrind: in an object with soname matching: ld-linux-armhf.so.3
valgrind: was not found whilst processing
valgrind: symbols from the object with soname: ld-linux-armhf.so.3
valgrind:
valgrind: Possible fixes: (1, short term): install glibc's debuginfo
valgrind: package on this machine. (2, longer term): ask the packagers
valgrind: for your Linux distribution to please in future ship a non-
valgrind: stripped ld.so (or whatever the dynamic linker .so is called)
valgrind: that exports the above-named function using the standard
valgrind: calling conventions for this platform. The package you need
valgrind: to install for fix (1) is called
valgrind:
valgrind: On Debian, Ubuntu: libc6-dbg
valgrind: On SuSE, openSuSE, Fedora, RHEL: glibc-debuginfo
valgrind:
valgrind: Note that if you are debugging a 32 bit process on a
valgrind: 64 bit system, you will need a corresponding 32 bit debuginfo
valgrind: package (e.g. libc6-dbg:i386).
valgrind:
valgrind: Cannot continue -- exiting now. Sorry.

Answer 1

I encountered the same problem, here is how I resolve it:
Replace the ld-xx.so in /lib path with a debug build.
Here is my case. I'm using Yocto to build rootfs, so copy poky/build/tmp/work/xxxx/glibc/2.26-r0/image/lib/ld-2.26.so from your build path to Linux FS path /lib, to replace original /lib/ld-2.26.so(and ld-linux-armhf.so.3) of release build.
After doing this, valgrind works fine.
WARNING: Exchanging the loader on a running system can brick it! These steps work:
Upload new loader to target to a path outside /lib
mark new loader as executable (chmod 755)
copy (don't move!) old loader
copy new loader to /lib

Answer 2

If the target is glibc, you need to make sure that .symtab is not stripped from the dynamic loader (/lib/ld-linux-armhf.so.3). valgrind needs these symbols to work.