linux-kernel - vmlinux.o: warning: objtool: nmi_panic+0x30: unreachable instruction

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Message-ID: <202208151234.YgufKC9A-lkp@intel.com>
Date:   Mon, 15 Aug 2022 12:58:48 +0800
From:   kernel test robot <lkp@...el.com>
To:     Borislav Petkov <bp@...e.de>
Cc:     kbuild-all@...ts.01.org, linux-kernel@...r.kernel.org,
        Peter Zijlstra <peterz@...radead.org>
Subject: vmlinux.o: warning: objtool: nmi_panic+0x30: unreachable instruction

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   568035b01cfb107af8d2e4bd2fb9aea22cf5b868
commit: 2028a255f4df3af9e759f01f958d3237f825f256 x86/extable: Annotate ex_handler_msr_mce() as a dead end
date:   3 months ago
config: x86_64-randconfig-a006-20220815 (https://download.01.org/0day-ci/archive/20220815/202208151234.YgufKC9A-lkp@intel.com/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/torvalds/linux.git/commit/?id=2028a255f4df3af9e759f01f958d3237f825f256
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout 2028a255f4df3af9e759f01f958d3237f825f256
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash

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

All warnings (new ones prefixed by >>):

>> vmlinux.o: warning: objtool: nmi_panic+0x30: unreachable instruction


objdump-func vmlinux.o nmi_panic:
0000 00000000000aeb50 <nmi_panic>:
0000    aeb50:	f3 0f 1e fa          	endbr64 
0004    aeb54:	55                   	push   %rbp
0005    aeb55:	48 89 e5             	mov    %rsp,%rbp
0008    aeb58:	65 8b 15 00 00 00 00 	mov    %gs:0x0(%rip),%edx        # aeb5f <nmi_panic+0xf>	aeb5b: R_X86_64_PC32	cpu_number-0x4
000f    aeb5f:	b8 ff ff ff ff       	mov    $0xffffffff,%eax
0014    aeb64:	f0 0f b1 15 00 00 00 00 	lock cmpxchg %edx,0x0(%rip)        # aeb6c <nmi_panic+0x1c>	aeb68: R_X86_64_PC32	panic_cpu-0x4
001c    aeb6c:	83 f8 ff             	cmp    $0xffffffff,%eax
001f    aeb6f:	0f 84 00 00 00 00    	je     aeb75 <nmi_panic+0x25>	aeb71: R_X86_64_PC32	.text.unlikely+0x886a
0025    aeb75:	39 c2                	cmp    %eax,%edx
0027    aeb77:	75 02                	jne    aeb7b <nmi_panic+0x2b>
0029    aeb79:	5d                   	pop    %rbp
002a    aeb7a:	c3                   	ret    
002b    aeb7b:	e8 00 00 00 00       	call   aeb80 <nmi_panic+0x30>	aeb7c: R_X86_64_PLT32	nmi_panic_self_stop-0x4
0030    aeb80:	5d                   	pop    %rbp
0031    aeb81:	c3                   	ret    
0032    aeb82:	66 66 2e 0f 1f 84 00 00 00 00 00 	data16 cs nopw 0x0(%rax,%rax,1)
003d    aeb8d:	0f 1f 00             	nopl   (%rax)
0000 000000000000886e <nmi_panic.cold>:
0000     886e:	48 c7 c7 00 00 00 00 	mov    $0x0,%rdi	8871: R_X86_64_32S	.rodata.str1.1+0x8244
0007     8875:	e8 00 00 00 00       	call   887a <add_taint.cold>	8876: R_X86_64_PLT32	panic-0x4

-- 
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https://01.org/lkp