Re: [PATCH] x86: livepatch: Treat R_X86_64_PLT32 as R_X86_64_PC32

[chengjian (D)]

Hi，Jiri


This patch should be merged into 4.4 stable,

which still use klp_write_module_reloc.


https://elixir.bootlin.com/linux/v4.4.174/source/arch/x86/kernel/livepatch.c


ZeFeng may have sent a stable(4.4-y) patch to the wrong mail-list(mainline).


Thanks.

On 2019/2/15 15:28, Jiri Kosina wrote:
> On Fri, 15 Feb 2019, chenzefeng (A) wrote:
>
> > On x86-64, for 32-bit PC-relacive branches, we can generate PLT32
> > relocation, instead of PC32 relocation. and R_X86_64_PLT32 can be
> > treated the same as R_X86_64_PC32 since linux kernel doesn't use PLT.
> >
> > In linux 4.4 commit b21ebf2fb4cd ("x86: Treat R_X86_64_PLT32 as
> > R_X86_64_PC32") been fixed for the module loading, but not fixed for
> > livepatch relocation, which will fail to load livepatch with the error
> > message as follow: relocation failed for symbol <symbol name> at <symbol
> > address>
> >
> > Signed-off-by: chenzefeng <chenzefeng2@xxxxxxxxxx>
> What kernel version is this patch based on? We've got rid of x86-specific
> module loading stub and offloaded all the relocation handling to generic
> kmod loader long time ago.