On Wed, Jan 18, 2023 at 12:47:28PM -0800, Song Liu wrote:

From: Miroslav Benes <mbenes@suse.cz>

Josh reported a bug:

  When the object to be patched is a module, and that module is
  rmmod'ed and reloaded, it fails to load with:

  module: x86/modules: Skipping invalid relocation target, existing value is nonzero for type 2, loc 00000000ba0302e9, val ffffffffa03e293c
  livepatch: failed to initialize patch 'livepatch_nfsd' for module 'nfsd' (-8)
  livepatch: patch 'livepatch_nfsd' failed for module 'nfsd', refusing to load module 'nfsd'

  The livepatch module has a relocation which references a symbol
  in the _previous_ loading of nfsd. When apply_relocate_add()
  tries to replace the old relocation with a new one, it sees that
  the previous one is nonzero and it errors out.

  On ppc64le, we have a similar issue:

  module_64: livepatch_nfsd: Expected nop after call, got e8410018 at e_show+0x60/0x548 [livepatch_nfsd]
  livepatch: failed to initialize patch 'livepatch_nfsd' for module 'nfsd' (-8)
  livepatch: patch 'livepatch_nfsd' failed for module 'nfsd', refusing to load module 'nfsd'

Shouldn't there also be a fix for this powerpc issue?

-- 
Josh