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

["gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>]

On Wed, Feb 20, 2019 at 12:37:54PM +0000, 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.
> 
> 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>
> 
> This issue only effacted the kernel version from 4.0 to 4.6, becauce the function klp_write_module_reloc is introduced by:
> commit b700e7f03df5 ("livepatch: kernel: add support for live patching") and deleted by: commit 425595a7fc20
> ("livepatch: reuse module loader code to write relocations")
> 
> Signed-off-by: chenzefeng <chenzefeng2@huawei.com>
> Reviewed-by: Petr Mladek <pmladek@suse.com>
> ---
>  arch/x86/kernel/livepatch.c | 1 +
>  1 file changed, 1 insertion(+)

Now queued up, thanks.

Also, next time please wrap your changelog text at 72 columns :)

greg k-h