[PATCH] drm/vblank: Require a driver register vblank support for 0 or all CRTCs

kernel test robot oliver.sang at intel.com
Thu Oct 10 06:49:51 UTC 2024



Hello,

kernel test robot noticed "BUG:kernel_NULL_pointer_dereference,address" on:

commit: 8e1a430cf308254a61a2317a0dfc4d8f4b3e13cb ("[PATCH] drm/vblank: Require a driver register vblank support for 0 or all CRTCs")
url: https://github.com/intel-lab-lkp/linux/commits/Lyude-Paul/drm-vblank-Require-a-driver-register-vblank-support-for-0-or-all-CRTCs/20240928-044210
patch link: https://lore.kernel.org/all/20240927203946.695934-2-lyude@redhat.com/
patch subject: [PATCH] drm/vblank: Require a driver register vblank support for 0 or all CRTCs

in testcase: boot

compiler: gcc-12
test machine: qemu-system-i386 -enable-kvm -cpu SandyBridge -smp 2 -m 4G

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


+---------------------------------------------+------------+------------+
|                                             | 22512c3ee0 | 8e1a430cf3 |
+---------------------------------------------+------------+------------+
| boot_successes                              | 12         | 0          |
| boot_failures                               | 0          | 12         |
| BUG:kernel_NULL_pointer_dereference,address | 0          | 12         |
| Oops:Oops:#[##]                             | 0          | 12         |
| EIP:drm_vblank_init                         | 0          | 12         |
| Kernel_panic-not_syncing:Fatal_exception    | 0          | 12         |
+---------------------------------------------+------------+------------+


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 at intel.com>
| Closes: https://lore.kernel.org/oe-lkp/202410101418.5704b4a5-lkp@intel.com


[    4.727010][    T1] BUG: kernel NULL pointer dereference, address: 00000188
[    4.728324][    T1] #PF: supervisor read access in kernel mode
[    4.729456][    T1] #PF: error_code(0x0000) - not-present page
[    4.729853][    T1] *pdpt = 0000000000000000 *pde = f000ff53f000ff53
[    4.729853][    T1] Oops: Oops: 0000 [#1]
[    4.729853][    T1] CPU: 0 UID: 0 PID: 1 Comm: swapper Tainted: G                T  6.11.0-rc7-01372-g8e1a430cf308 #1 577dd3e1adc1bccd6f381550d3179686c5f157a0
[    4.729853][    T1] Tainted: [T]=RANDSTRUCT
[    4.729853][    T1] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
[ 4.729853][ T1] EIP: drm_vblank_init (drivers/gpu/drm/drm_vblank.c:534) 
[ 4.729853][ T1] Code: 89 c6 53 83 ec 08 89 55 ec 8b 90 64 05 00 00 39 d1 74 56 8d 42 f8 eb 12 90 8b 5a 04 85 db 74 17 8b 50 08 8d 42 f8 39 d1 74 3f <8b> 90 90 01 00 00 8b 7a 08 85 ff 75 e2 8b 40 10 85 f6 74 03 8b 76
All code
========
   0:	89 c6                	mov    %eax,%esi
   2:	53                   	push   %rbx
   3:	83 ec 08             	sub    $0x8,%esp
   6:	89 55 ec             	mov    %edx,-0x14(%rbp)
   9:	8b 90 64 05 00 00    	mov    0x564(%rax),%edx
   f:	39 d1                	cmp    %edx,%ecx
  11:	74 56                	je     0x69
  13:	8d 42 f8             	lea    -0x8(%rdx),%eax
  16:	eb 12                	jmp    0x2a
  18:	90                   	nop
  19:	8b 5a 04             	mov    0x4(%rdx),%ebx
  1c:	85 db                	test   %ebx,%ebx
  1e:	74 17                	je     0x37
  20:	8b 50 08             	mov    0x8(%rax),%edx
  23:	8d 42 f8             	lea    -0x8(%rdx),%eax
  26:	39 d1                	cmp    %edx,%ecx
  28:	74 3f                	je     0x69
  2a:*	8b 90 90 01 00 00    	mov    0x190(%rax),%edx		<-- trapping instruction
  30:	8b 7a 08             	mov    0x8(%rdx),%edi
  33:	85 ff                	test   %edi,%edi
  35:	75 e2                	jne    0x19
  37:	8b 40 10             	mov    0x10(%rax),%eax
  3a:	85 f6                	test   %esi,%esi
  3c:	74 03                	je     0x41
  3e:	8b                   	.byte 0x8b
  3f:	76                   	.byte 0x76

Code starting with the faulting instruction
===========================================
   0:	8b 90 90 01 00 00    	mov    0x190(%rax),%edx
   6:	8b 7a 08             	mov    0x8(%rdx),%edi
   9:	85 ff                	test   %edi,%edi
   b:	75 e2                	jne    0xffffffffffffffef
   d:	8b 40 10             	mov    0x10(%rax),%eax
  10:	85 f6                	test   %esi,%esi
  12:	74 03                	je     0x17
  14:	8b                   	.byte 0x8b
  15:	76                   	.byte 0x76
[    4.729853][    T1] EAX: fffffff8 EBX: 86802000 ECX: 86802564 EDX: 00000000
[    4.729853][    T1] ESI: 86802000 EDI: 86813400 EBP: 85e1fe90 ESP: 85e1fe7c
[    4.729853][    T1] DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068 EFLAGS: 00010282
[    4.729853][    T1] CR0: 80050033 CR2: 00000188 CR3: 05182000 CR4: 000406b0
[    4.729853][    T1] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[    4.729853][    T1] DR6: fffe0ff0 DR7: 00000400
[    4.729853][    T1] Call Trace:
[ 4.729853][ T1] ? show_regs (arch/x86/kernel/dumpstack.c:478) 
[ 4.729853][ T1] ? __die (arch/x86/kernel/dumpstack.c:421 arch/x86/kernel/dumpstack.c:434) 
[ 4.729853][ T1] ? page_fault_oops (arch/x86/mm/fault.c:715) 
[ 4.729853][ T1] ? kernelmode_fixup_or_oops+0x54/0x68 
[ 4.729853][ T1] ? __bad_area_nosemaphore+0x103/0x180 
[ 4.729853][ T1] ? sched_clock_noinstr (arch/x86/kernel/tsc.c:267) 
[ 4.729853][ T1] ? bad_area_nosemaphore (arch/x86/mm/fault.c:835) 
[ 4.729853][ T1] ? do_user_addr_fault (arch/x86/mm/fault.c:1452) 
[ 4.729853][ T1] ? exc_page_fault (arch/x86/include/asm/irqflags.h:26 arch/x86/include/asm/irqflags.h:87 arch/x86/include/asm/irqflags.h:147 arch/x86/mm/fault.c:1489 arch/x86/mm/fault.c:1539) 
[ 4.729853][ T1] ? pvclock_clocksource_read_nowd (arch/x86/mm/fault.c:1494) 
[ 4.729853][ T1] ? handle_exception (arch/x86/entry/entry_32.S:1054) 
[ 4.729853][ T1] ? pvclock_clocksource_read_nowd (arch/x86/mm/fault.c:1494) 
[ 4.729853][ T1] ? drm_vblank_init (drivers/gpu/drm/drm_vblank.c:534) 
[ 4.729853][ T1] ? pvclock_clocksource_read_nowd (arch/x86/mm/fault.c:1494) 
[ 4.729853][ T1] ? drm_vblank_init (drivers/gpu/drm/drm_vblank.c:534) 
[ 4.729853][ T1] vkms_create (drivers/gpu/drm/vkms/vkms_drv.c:211) 
[ 4.729853][ T1] vkms_init (drivers/gpu/drm/vkms/vkms_drv.c:254) 
[ 4.729853][ T1] ? vgem_init (drivers/gpu/drm/vkms/vkms_drv.c:240) 
[ 4.729853][ T1] do_one_initcall (init/main.c:1267) 
[ 4.729853][ T1] do_initcalls (init/main.c:1328 init/main.c:1345) 
[ 4.729853][ T1] kernel_init_freeable (init/main.c:1580) 
[ 4.729853][ T1] ? rest_init (init/main.c:1459) 
[ 4.729853][ T1] kernel_init (init/main.c:1469) 
[ 4.729853][ T1] ret_from_fork (arch/x86/kernel/process.c:153) 
[ 4.729853][ T1] ? rest_init (init/main.c:1459) 
[ 4.729853][ T1] ret_from_fork_asm (arch/x86/entry/entry_32.S:737) 
[ 4.729853][ T1] entry_INT80_32 (arch/x86/entry/entry_32.S:944) 
[    4.729853][    T1] Modules linked in:
[    4.729853][    T1] CR2: 0000000000000188
[    4.729853][    T1] ---[ end trace 0000000000000000 ]---
[ 4.729853][ T1] EIP: drm_vblank_init (drivers/gpu/drm/drm_vblank.c:534) 
[ 4.729853][ T1] Code: 89 c6 53 83 ec 08 89 55 ec 8b 90 64 05 00 00 39 d1 74 56 8d 42 f8 eb 12 90 8b 5a 04 85 db 74 17 8b 50 08 8d 42 f8 39 d1 74 3f <8b> 90 90 01 00 00 8b 7a 08 85 ff 75 e2 8b 40 10 85 f6 74 03 8b 76
All code
========
   0:	89 c6                	mov    %eax,%esi
   2:	53                   	push   %rbx
   3:	83 ec 08             	sub    $0x8,%esp
   6:	89 55 ec             	mov    %edx,-0x14(%rbp)
   9:	8b 90 64 05 00 00    	mov    0x564(%rax),%edx
   f:	39 d1                	cmp    %edx,%ecx
  11:	74 56                	je     0x69
  13:	8d 42 f8             	lea    -0x8(%rdx),%eax
  16:	eb 12                	jmp    0x2a
  18:	90                   	nop
  19:	8b 5a 04             	mov    0x4(%rdx),%ebx
  1c:	85 db                	test   %ebx,%ebx
  1e:	74 17                	je     0x37
  20:	8b 50 08             	mov    0x8(%rax),%edx
  23:	8d 42 f8             	lea    -0x8(%rdx),%eax
  26:	39 d1                	cmp    %edx,%ecx
  28:	74 3f                	je     0x69
  2a:*	8b 90 90 01 00 00    	mov    0x190(%rax),%edx		<-- trapping instruction
  30:	8b 7a 08             	mov    0x8(%rdx),%edi
  33:	85 ff                	test   %edi,%edi
  35:	75 e2                	jne    0x19
  37:	8b 40 10             	mov    0x10(%rax),%eax
  3a:	85 f6                	test   %esi,%esi
  3c:	74 03                	je     0x41
  3e:	8b                   	.byte 0x8b
  3f:	76                   	.byte 0x76

Code starting with the faulting instruction
===========================================
   0:	8b 90 90 01 00 00    	mov    0x190(%rax),%edx
   6:	8b 7a 08             	mov    0x8(%rdx),%edi
   9:	85 ff                	test   %edi,%edi
   b:	75 e2                	jne    0xffffffffffffffef
   d:	8b 40 10             	mov    0x10(%rax),%eax
  10:	85 f6                	test   %esi,%esi
  12:	74 03                	je     0x17
  14:	8b                   	.byte 0x8b
  15:	76                   	.byte 0x76


The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20241010/202410101418.5704b4a5-lkp@intel.com



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



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