Re: [PATCH 1/4] x86/percpu: Use explicit segment registers in lib/cmpxchg{8,16}b_emu.S

[kernel test robot <oliver.sang@intel.com>]

Hello,

kernel test robot noticed "general_protection_fault:#[##]" on:

commit: 33c7952d925e905f7af1fb7628e48e03f59885da ("[PATCH 1/4] x86/percpu: Use explicit segment registers in lib/cmpxchg{8,16}b_emu.S")
url: https://github.com/intel-lab-lkp/linux/commits/Uros-Bizjak/x86-percpu-Use-explicit-segment-registers-in-lib-cmpxchg-8-16-b_emu-S/20231017-111304
base: https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git 92fe9bb77b0c9fade150350fdb0629a662f0923f
patch link: https://lore.kernel.org/all/20231012161237.114733-2-ubizjak@gmail.com/
patch subject: [PATCH 1/4] x86/percpu: Use explicit segment registers in lib/cmpxchg{8,16}b_emu.S

in testcase: boot

compiler: gcc-12
test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 16G

(please refer to attached dmesg/kmsg for entire log/backtrace)


+------------------------------------------+------------+------------+
|                                          | 92fe9bb77b | 33c7952d92 |
+------------------------------------------+------------+------------+
| boot_successes                           | 7          | 0          |
| boot_failures                            | 0          | 7          |
| general_protection_fault:#[##]           | 0          | 7          |
| EIP:this_cpu_cmpxchg8b_emu               | 0          | 7          |
| Kernel_panic-not_syncing:Fatal_exception | 0          | 7          |
+------------------------------------------+------------+------------+


If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <oliver.sang@intel.com>
| Closes: https://lore.kernel.org/oe-lkp/202310261417.b269d37e-oliver.sang@intel.com


[    0.186570][    T0] stackdepot hash table entries: 65536 (order: 6, 262144 bytes, linear)
[    0.187499][    T0] Initializing HighMem for node 0 (0002ebfe:000bffe0)
[    1.727965][    T0] Initializing Movable for node 0 (00000000:00000000)
[    1.943274][    T0] Checking if this processor honours the WP bit even in supervisor mode...Ok.
[    1.944313][    T0] Memory: 2896220K/3145208K available (16182K kernel code, 5537K rwdata, 11756K rodata, 816K init, 9720K bss, 248988K reserved, 0K cma-reserved, 2379656K highmem)
[    1.947172][    T0] general protection fault: 0000 [#1] PREEMPT
[    1.947900][    T0] CPU: 0 PID: 0 Comm: swapper Not tainted 6.6.0-rc1-00024-g33c7952d925e #1 8d4b014f9a0a85cc9a3f6a52ed8e88f1e431f74e
[    1.949317][    T0] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
[ 1.950480][ T0] EIP: this_cpu_cmpxchg8b_emu (kbuild/src/consumer/arch/x86/lib/cmpxchg8b_emu.S:73) 
[ 1.951093][ T0] Code: ff ff ff 8d b4 26 00 00 00 00 66 90 83 c6 01 3c 3d 0f 95 c0 0f b6 c0 83 c0 01 e9 56 ff ff ff bf ff ff ff ff eb a6 cc cc 9c fa <64> 3b 06 75 13 64 3b 56 04 75 0d 64 89 1e 64 89 4e 04 83 0c 24 40
All code
========
   0:	ff                   	(bad)
   1:	ff                   	(bad)
   2:	ff 8d b4 26 00 00    	decl   0x26b4(%rbp)
   8:	00 00                	add    %al,(%rax)
   a:	66 90                	xchg   %ax,%ax
   c:	83 c6 01             	add    $0x1,%esi
   f:	3c 3d                	cmp    $0x3d,%al
  11:	0f 95 c0             	setne  %al
  14:	0f b6 c0             	movzbl %al,%eax
  17:	83 c0 01             	add    $0x1,%eax
  1a:	e9 56 ff ff ff       	jmp    0xffffffffffffff75
  1f:	bf ff ff ff ff       	mov    $0xffffffff,%edi
  24:	eb a6                	jmp    0xffffffffffffffcc
  26:	cc                   	int3
  27:	cc                   	int3
  28:	9c                   	pushf
  29:	fa                   	cli
  2a:*	64 3b 06             	cmp    %fs:(%rsi),%eax		<-- trapping instruction
  2d:	75 13                	jne    0x42
  2f:	64 3b 56 04          	cmp    %fs:0x4(%rsi),%edx
  33:	75 0d                	jne    0x42
  35:	64 89 1e             	mov    %ebx,%fs:(%rsi)
  38:	64 89 4e 04          	mov    %ecx,%fs:0x4(%rsi)
  3c:	83 0c 24 40          	orl    $0x40,(%rsp)

Code starting with the faulting instruction
===========================================
   0:	64 3b 06             	cmp    %fs:(%rsi),%eax
   3:	75 13                	jne    0x18
   5:	64 3b 56 04          	cmp    %fs:0x4(%rsi),%edx
   9:	75 0d                	jne    0x18
   b:	64 89 1e             	mov    %ebx,%fs:(%rsi)
   e:	64 89 4e 04          	mov    %ecx,%fs:0x4(%rsi)
  12:	83 0c 24 40          	orl    $0x40,(%rsp)
[    1.953397][    T0] EAX: c3c01100 EBX: c3c01180 ECX: 00000004 EDX: 00000003
[    1.954231][    T0] ESI: e52cd090 EDI: e52cd090 EBP: c2b4bf00 ESP: c2b4bec4
[    1.955060][    T0] DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068 EFLAGS: 00210082
[    1.955949][    T0] CR0: 80050033 CR2: ffdeb000 CR3: 031b5000 CR4: 00000090
[    1.956783][    T0] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[    1.957641][    T0] DR6: fffe0ff0 DR7: 00000400
[    1.958190][    T0] Call Trace:
[ 1.958554][ T0] ? show_regs (kbuild/src/consumer/arch/x86/kernel/dumpstack.c:479) 
[ 1.959026][ T0] ? die_addr (kbuild/src/consumer/arch/x86/kernel/dumpstack.c:421 kbuild/src/consumer/arch/x86/kernel/dumpstack.c:460) 
[ 1.959480][ T0] ? exc_general_protection (kbuild/src/consumer/arch/x86/kernel/traps.c:697 kbuild/src/consumer/arch/x86/kernel/traps.c:642) 
[ 1.960101][ T0] ? exc_bounds (kbuild/src/consumer/arch/x86/kernel/traps.c:642) 
[ 1.960579][ T0] ? handle_exception (kbuild/src/consumer/arch/x86/entry/entry_32.S:1049) 


The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20231026/202310261417.b269d37e-oliver.sang@intel.com



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0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki