Greeting, FYI, we noticed the following commit (built with gcc-9): commit: d7b8e363d025cb61b9fbcee829ce69ff82393e78 ("[net-next, v4, 02/11] ptp: support ptp physical/virtual clocks conversion") url: https://github.com/0day-ci/linux/commits/Yangbo-Lu/ptp-support-virtual-cl... 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): +-------------------------------------------------+------------+------------+ | | fd3836e9bc | d7b8e363d0 | +-------------------------------------------------+------------+------------+ | boot_successes | 17 | 0 | | BUG:kernel_NULL_pointer_dereference,address | 0 | 35 | | Oops:#[##] | 0 | 35 | | EIP:ptp_clock_register | 0 | 35 | | Kernel_panic-not_syncing:Fatal_exception | 0 | 35 | +-------------------------------------------------+------------+------------+ If you fix the issue, kindly add following tag Reported-by: kernel test robot <oliver.sang(a)intel.com&gt; [ 1.357423] BUG: kernel NULL pointer dereference, address: 00000190 [ 1.358353] #PF: supervisor read access in kernel mode [ 1.358353] #PF: error_code(0x0000) - not-present page [ 1.358353] *pde = 00000000 [ 1.358353] Oops: 0000 [#1] SMP [ 1.358353] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.13.0-rc6-02069-gd7b8e363d025 #1 [ 1.363334] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 [ 1.363334] EIP: ptp_clock_register (drivers/ptp/ptp_clock.c:236) [ 1.363334] Code: ff ff b3 34 02 00 00 68 e3 7a f9 ca 6a 00 e8 28 29 8e ff 89 83 a8 12 00 00 83 c4 14 3d 00 f0 ff ff 0f 87 07 95 36 00 8b 45 9c <8b> 80 90 01 00 00 85 c0 0f 84 33 01 00 00 8b 00 ba 9c 7a f9 ca e8 All code ======== 0: ff (bad) 1: ff b3 34 02 00 00 pushq 0x234(%rbx) 7: 68 e3 7a f9 ca pushq $0xffffffffcaf97ae3 c: 6a 00 pushq $0x0 e: e8 28 29 8e ff callq 0xffffffffff8e293b 13: 89 83 a8 12 00 00 mov %eax,0x12a8(%rbx) 19: 83 c4 14 add $0x14,%esp 1c: 3d 00 f0 ff ff cmp $0xfffff000,%eax 21: 0f 87 07 95 36 00 ja 0x36952e 27: 8b 45 9c mov -0x64(%rbp),%eax 2a:* 8b 80 90 01 00 00 mov 0x190(%rax),%eax <-- trapping instruction 30: 85 c0 test %eax,%eax 32: 0f 84 33 01 00 00 je 0x16b 38: 8b 00 mov (%rax),%eax 3a: ba 9c 7a f9 ca mov $0xcaf97a9c,%edx 3f: e8 .byte 0xe8 Code starting with the faulting instruction =========================================== 0: 8b 80 90 01 00 00 mov 0x190(%rax),%eax 6: 85 c0 test %eax,%eax 8: 0f 84 33 01 00 00 je 0x141 e: 8b 00 mov (%rax),%eax 10: ba 9c 7a f9 ca mov $0xcaf97a9c,%edx 15: e8 .byte 0xe8 [ 1.363334] EAX: 00000000 EBX: c12bc000 ECX: 00000000 EDX: c12bd278 [ 1.363334] ESI: cb67d904 EDI: 0fc00000 EBP: c10c5f1c ESP: c10c5eb4 [ 1.363334] DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 EFLAGS: 00010246 [ 1.363334] CR0: 80050033 CR2: 00000190 CR3: 0b540000 CR4: 000406d0 [ 1.363334] Call Trace: [ 1.363334] ? kobject_uevent (lib/kobject_uevent.c:643) [ 1.363334] ? ptp_init (drivers/ptp/ptp_kvm_common.c:136) [ 1.363334] ? slow_virt_to_phys (arch/x86/mm/pat/set_memory.c:704) [ 1.363334] ptp_kvm_init (include/linux/err.h:31 include/linux/err.h:60 drivers/ptp/ptp_kvm_common.c:150) [ 1.363334] ? ptp_init (drivers/ptp/ptp_kvm_common.c:136) [ 1.363334] do_one_initcall (init/main.c:1249) [ 1.363334] ? rdinit_setup (init/main.c:1308) [ 1.363334] kernel_init_freeable (init/main.c:1321 init/main.c:1338 init/main.c:1358 init/main.c:1560) [ 1.363334] ? rest_init (init/main.c:1444) [ 1.363334] kernel_init (init/main.c:1449) [ 1.363334] ret_from_fork (arch/x86/entry/entry_32.S:775) [ 1.363334] Modules linked in: [ 1.363334] CR2: 0000000000000190 [ 1.363334] ---[ end trace 3b8fb0506f39eed9 ]--- [ 1.363334] EIP: ptp_clock_register (drivers/ptp/ptp_clock.c:236) [ 1.363334] Code: ff ff b3 34 02 00 00 68 e3 7a f9 ca 6a 00 e8 28 29 8e ff 89 83 a8 12 00 00 83 c4 14 3d 00 f0 ff ff 0f 87 07 95 36 00 8b 45 9c <8b> 80 90 01 00 00 85 c0 0f 84 33 01 00 00 8b 00 ba 9c 7a f9 ca e8 All code ======== 0: ff (bad) 1: ff b3 34 02 00 00 pushq 0x234(%rbx) 7: 68 e3 7a f9 ca pushq $0xffffffffcaf97ae3 c: 6a 00 pushq $0x0 e: e8 28 29 8e ff callq 0xffffffffff8e293b 13: 89 83 a8 12 00 00 mov %eax,0x12a8(%rbx) 19: 83 c4 14 add $0x14,%esp 1c: 3d 00 f0 ff ff cmp $0xfffff000,%eax 21: 0f 87 07 95 36 00 ja 0x36952e 27: 8b 45 9c mov -0x64(%rbp),%eax 2a:* 8b 80 90 01 00 00 mov 0x190(%rax),%eax <-- trapping instruction 30: 85 c0 test %eax,%eax 32: 0f 84 33 01 00 00 je 0x16b 38: 8b 00 mov (%rax),%eax 3a: ba 9c 7a f9 ca mov $0xcaf97a9c,%edx 3f: e8 .byte 0xe8 Code starting with the faulting instruction =========================================== 0: 8b 80 90 01 00 00 mov 0x190(%rax),%eax 6: 85 c0 test %eax,%eax 8: 0f 84 33 01 00 00 je 0x141 e: 8b 00 mov (%rax),%eax 10: ba 9c 7a f9 ca mov $0xcaf97a9c,%edx 15: e8 .byte 0xe8 To reproduce: # build kernel cd linux cp config-5.13.0-rc6-02069-gd7b8e363d025 .config make HOSTCC=gcc-9 CC=gcc-9 ARCH=i386 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