[linux-stable-rc:linux-5.10.y 6996/7120] arch/x86/kernel/ftrace_64.o: warning: objtool: ftrace_epilogue()+0x10: unreachable instruction

From: kernel test robot
Date: Tue Jul 12 2022 - 15:57:37 EST

tree: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-5.10.y
head: ba398a0e54049bb6a1c102245ae84103f103ff2c
commit: 8ca9dceaa17983afec1cc8e1a6e76d6bd142447a [6996/7120] objtool: Assume only ELF functions do sibling calls
config: x86_64-rhel-8.3-syz (https://download.01.org/0day-ci/archive/20220713/202207130344.dwXyDmTk-lkp@xxxxxxxxx/config)
compiler: gcc-11 (Debian 11.3.0-3) 11.3.0
reproduce (this is a W=1 build):
# https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git/commit/?id=8ca9dceaa17983afec1cc8e1a6e76d6bd142447a
git remote add linux-stable-rc https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git
git fetch --no-tags linux-stable-rc linux-5.10.y
git checkout 8ca9dceaa17983afec1cc8e1a6e76d6bd142447a
# save the config file
mkdir build_dir && cp config build_dir/.config
make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash arch/x86/

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

>> arch/x86/kernel/ftrace_64.o: warning: objtool: ftrace_epilogue()+0x10: unreachable instruction

objdump-func vmlinux.o ftrace_epilogue:
0000 000000000008ca70 <ftrace_epilogue>:
0000 8ca70: e9 00 00 00 00 jmp 8ca75 <ftrace_epilogue+0x5> 8ca71: R_X86_64_PLT32 ftrace_stub-0x4
0005 8ca75: 66 66 2e 0f 1f 84 00 00 00 00 00 data16 cs nopw 0x0(%rax,%rax,1)

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