Greeting,

FYI, we noticed the following commit (built with gcc-9):

commit: 8e614d5b58992e722f07de7c2426f2c44668092b ("clocksource: Provide kernel module to test clocksource watchdog")
https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master


in testcase: boot

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

caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace):


+-------------------------------------------------------------------------+------------+------------+
|                                                                         | bdbd9c673e | 8e614d5b58 |
+-------------------------------------------------------------------------+------------+------------+
| WARNING:at_kernel/time/clocksource-wdtest.c:#wdtest_func.cold           | 0          | 11         |
| RIP:wdtest_func.cold                                                    | 0          | 11         |
+-------------------------------------------------------------------------+------------+------------+


If you fix the issue, kindly add following tag
Reported-by: kernel test robot <oliver.sang@intel.com>


[  123.866590] WARNING: CPU: 1 PID: 221 at kernel/time/clocksource-wdtest.c:153 wdtest_func.cold (kbuild/src/consumer/kernel/time/clocksource-wdtest.c:153 (discriminator 4)) 
[  123.870382] Modules linked in:
[  123.871899] CPU: 1 PID: 221 Comm: wdtest Not tainted 5.12.0-rc5-00005-g8e614d5b5899 #1
[  123.875044] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
[  123.878324] RIP: 0010:wdtest_func.cold (kbuild/src/consumer/kernel/time/clocksource-wdtest.c:153 (discriminator 4)) 
[ 123.880459] Code: 00 00 44 89 25 87 bf d7 11 e8 02 7e a0 00 44 8b 2d 7b bf d7 11 31 ff 44 89 ee e8 91 52 13 f6 45 85 ed 74 09 e8 c7 50 13 f6 90 <0f> 0b 90 e8 be 50 13 f6 48 c7 c7 a0 94 78 a1 e8 72 1e 4a f6 4c 8b
All code
========
   0:	00 00                	add    %al,(%rax)
   2:	44 89 25 87 bf d7 11 	mov    %r12d,0x11d7bf87(%rip)        # 0x11d7bf90
   9:	e8 02 7e a0 00       	callq  0xa07e10
   e:	44 8b 2d 7b bf d7 11 	mov    0x11d7bf7b(%rip),%r13d        # 0x11d7bf90
  15:	31 ff                	xor    %edi,%edi
  17:	44 89 ee             	mov    %r13d,%esi
  1a:	e8 91 52 13 f6       	callq  0xfffffffff61352b0
  1f:	45 85 ed             	test   %r13d,%r13d
  22:	74 09                	je     0x2d
  24:	e8 c7 50 13 f6       	callq  0xfffffffff61350f0
  29:	90                   	nop
  2a:*	0f 0b                	ud2    		<-- trapping instruction
  2c:	90                   	nop
  2d:	e8 be 50 13 f6       	callq  0xfffffffff61350f0
  32:	48 c7 c7 a0 94 78 a1 	mov    $0xffffffffa17894a0,%rdi
  39:	e8 72 1e 4a f6       	callq  0xfffffffff64a1eb0
  3e:	4c                   	rex.WR
  3f:	8b                   	.byte 0x8b

Code starting with the faulting instruction
===========================================
   0:	0f 0b                	ud2    
   2:	90                   	nop
   3:	e8 be 50 13 f6       	callq  0xfffffffff61350c6
   8:	48 c7 c7 a0 94 78 a1 	mov    $0xffffffffa17894a0,%rdi
   f:	e8 72 1e 4a f6       	callq  0xfffffffff64a1e86
  14:	4c                   	rex.WR
  15:	8b                   	.byte 0x8b
[  123.895351] RSP: 0000:ffffc90000617ee8 EFLAGS: 00010246
[  123.897547] RAX: 0000000000000000 RBX: 0000000000000003 RCX: ffffffff97c8448f
[  123.900366] RDX: 0000000000000000 RSI: ffff888116751000 RDI: 0000000000000002
[  123.903304] RBP: ffffffff98d2b040 R08: 0000000000000001 R09: 0000000000000001
[  123.906043] R10: ffffffffabfac92b R11: fffffbfff57f5925 R12: 0000000000000003
[  123.908754] R13: 0000000000000003 R14: ffffffff98d2b040 R15: 0000000000000000
[  123.911564] FS:  0000000000000000(0000) GS:ffff88839d000000(0000) knlGS:0000000000000000
[  123.914936] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  123.917199] CR2: 0000000000000000 CR3: 0000000067cba000 CR4: 00000000000006e0
[  123.919858] Call Trace:
[  123.921124] ? wdtest_ktime_read (kbuild/src/consumer/kernel/time/clocksource-wdtest.c:106) 
[  123.922819] kthread (kbuild/src/consumer/kernel/kthread.c:292) 
[  123.924411] ? kthread_insert_work_sanity_check (kbuild/src/consumer/kernel/kthread.c:245) 
[  123.926635] ret_from_fork (kbuild/src/consumer/arch/x86/entry/entry_64.S:300) 
[  123.933080] irq event stamp: 645
[  123.934547] hardirqs last enabled at (653): console_unlock (kbuild/src/consumer/kernel/printk/printk.c:2605 (discriminator 1)) 
[  123.938065] hardirqs last disabled at (662): console_unlock (kbuild/src/consumer/kernel/printk/printk.c:2520 (discriminator 1)) 
[  123.941502] softirqs last enabled at (414): __do_softirq (kbuild/src/consumer/arch/x86/include/asm/preempt.h:27 kbuild/src/consumer/kernel/softirq.c:373) 
[  123.944829] softirqs last disabled at (407): irq_exit_rcu (kbuild/src/consumer/kernel/softirq.c:221 kbuild/src/consumer/kernel/softirq.c:422 kbuild/src/consumer/kernel/softirq.c:434) 
[  123.948225] _warn_unseeded_randomness: 7 callbacks suppressed
[  123.948286] random: get_random_bytes called from print_oops_end_marker+0x3b/0x60 with crng_init=0 
[  123.948378] ---[ end trace 66b1de777cc6b4b9 ]---
[  123.957630] clocksource_wdtest: --- Watchdog with 4x error injection, 3 retries, expect clock skew.
[  125.976675] ------------[ cut here ]------------


To reproduce:

        # build kernel
	cd linux
	cp config-5.12.0-rc5-00005-g8e614d5b5899 .config
	make HOSTCC=gcc-9 CC=gcc-9 ARCH=x86_64 olddefconfig prepare modules_prepare bzImage

        git clone https://github.com/intel/lkp-tests.git
        cd lkp-tests
        bin/lkp qemu -k <bzImage> job-script # job-script is attached in this email



---
0DAY/LKP+ Test Infrastructure                   Open Source Technology Center
https://lists.01.org/hyperkitty/list/lkp@lists.01.org       Intel Corporation

Thanks,
Oliver Sang