On Wed, Jan 18, 2023 at 2:08 PM Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote: > > On Wed, Jan 18, 2023 at 12:47:28PM -0800, Song Liu wrote: > > From: Miroslav Benes <mbenes@xxxxxxx> > > > > 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? There was a working version, but it was not very clean. We couldn't agree on the path forward for powerpc, so we are hoping to ship the fix to x86 (and s390?) first [1]. Thanks, Song [1] https://lore.kernel.org/live-patching/Y7hLvpHqgY0oJ4GY@alley/#t
