Commit f5aebe74 authored by chenzefeng (A)'s avatar chenzefeng (A) Committed by Greg Kroah-Hartman

x86: livepatch: Treat R_X86_64_PLT32 as R_X86_64_PC32

Signed-off-by: default avatarchenzefeng <chenzefeng2@huawei.com>

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 b21ebf2f ("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 b700e7f0
("livepatch: kernel: add support for live patching") and deleted by:
commit 425595a7 ("livepatch: reuse module loader code to write
relocations")
Signed-off-by: default avatarchenzefeng <chenzefeng2@huawei.com>
Reviewed-by: default avatarPetr Mladek <pmladek@suse.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 01fb3606
......@@ -58,6 +58,7 @@ int klp_write_module_reloc(struct module *mod, unsigned long type,
val = (s32)value;
break;
case R_X86_64_PC32:
case R_X86_64_PLT32:
val = (u32)(value - loc);
break;
default:
......
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