Linux Kernel Performance
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From: kernel test robot <oliver.sang@intel.com>
To: "Jim Cromie" <jim.cromie@gmail.com>,
	"Łukasz Bartosik" <ukaszb@chromium.org>
Cc: <oe-lkp@lists.linux.dev>, <lkp@intel.com>, <oliver.sang@intel.com>
Subject: [jimc:wk-merge] [dyndbg]  d718f31771: BUG:kernel_NULL_pointer_dereference,address
Date: Mon, 15 Jun 2026 22:16:24 +0800	[thread overview]
Message-ID: <202606152239.7c9bee0c-lkp@intel.com> (raw)



Hello,

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

commit: d718f3177198f6703c60bd009f5685f5eabd5db1 ("dyndbg: consolidate site ranges")
https://github.com/jimc/linux.git wk-merge

in testcase: boot

config: i386-randconfig-016-20260614
compiler: clang-22
test machine: qemu-system-i386 -enable-kvm -cpu SandyBridge -smp 2 -m 4G

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


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/202606152239.7c9bee0c-lkp@intel.com



[   26.968728][   T76] BUG: kernel NULL pointer dereference, address: 00000000
[   26.970219][   T76] #PF: supervisor read access in kernel mode
[   26.971419][   T76] #PF: error_code(0x0000) - not-present page
[   26.972635][   T76] *pde = 00000000
[   26.973405][   T76] Oops: Oops: 0000 [#1]
[   26.974262][   T76] CPU: 0 UID: 0 PID: 76 Comm: modprobe Tainted: G        W           7.1.0-rc7+ #1 PREEMPT(lazy)  c6420a15eeaf166da8d1dae05d67320060b21950
[   26.977057][   T76] Tainted: [W]=WARN
[   26.977839][   T76] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[   26.979974][   T76] EIP: strcmp (x86/lib/string_32.c:97)
[   26.980822][   T76] Code: ac aa 84 c0 75 f7 31 c0 aa 89 d8 83 c4 04 5e 5f 5b 5d c3 90 90 90 90 90 90 90 90 90 90 90 90 90 55 89 e5 57 56 89 c6 89 d7 ac <ae> 75 08 84 c0 75 f8 31 c0 eb 04 19 c0 0c 01 5e 5f 5d c3 90 90 90
All code
========
   0:	ac                   	lods   %ds:(%rsi),%al
   1:	aa                   	stos   %al,%es:(%rdi)
   2:	84 c0                	test   %al,%al
   4:	75 f7                	jne    0xfffffffffffffffd
   6:	31 c0                	xor    %eax,%eax
   8:	aa                   	stos   %al,%es:(%rdi)
   9:	89 d8                	mov    %ebx,%eax
   b:	83 c4 04             	add    $0x4,%esp
   e:	5e                   	pop    %rsi
   f:	5f                   	pop    %rdi
  10:	5b                   	pop    %rbx
  11:	5d                   	pop    %rbp
  12:	c3                   	ret
  13:	90                   	nop
  14:	90                   	nop
  15:	90                   	nop
  16:	90                   	nop
  17:	90                   	nop
  18:	90                   	nop
  19:	90                   	nop
  1a:	90                   	nop
  1b:	90                   	nop
  1c:	90                   	nop
  1d:	90                   	nop
  1e:	90                   	nop
  1f:	90                   	nop
  20:	55                   	push   %rbp
  21:	89 e5                	mov    %esp,%ebp
  23:	57                   	push   %rdi
  24:	56                   	push   %rsi
  25:	89 c6                	mov    %eax,%esi
  27:	89 d7                	mov    %edx,%edi
  29:	ac                   	lods   %ds:(%rsi),%al
  2a:*	ae                   	scas   %es:(%rdi),%al		<-- trapping instruction
  2b:	75 08                	jne    0x35
  2d:	84 c0                	test   %al,%al
  2f:	75 f8                	jne    0x29
  31:	31 c0                	xor    %eax,%eax
  33:	eb 04                	jmp    0x39
  35:	19 c0                	sbb    %eax,%eax
  37:	0c 01                	or     $0x1,%al
  39:	5e                   	pop    %rsi
  3a:	5f                   	pop    %rdi
  3b:	5d                   	pop    %rbp
  3c:	c3                   	ret
  3d:	90                   	nop
  3e:	90                   	nop
  3f:	90                   	nop

Code starting with the faulting instruction
===========================================
   0:	ae                   	scas   %es:(%rdi),%al
   1:	75 08                	jne    0xb
   3:	84 c0                	test   %al,%al
   5:	75 f8                	jne    0xffffffffffffffff
   7:	31 c0                	xor    %eax,%eax
   9:	eb 04                	jmp    0xf
   b:	19 c0                	sbb    %eax,%eax
   d:	0c 01                	or     $0x1,%al
   f:	5e                   	pop    %rsi
  10:	5f                   	pop    %rdi
  11:	5d                   	pop    %rbp
  12:	c3                   	ret
  13:	90                   	nop
  14:	90                   	nop
  15:	90                   	nop
[   26.984699][   T76] EAX: f81b5262 EBX: f81b52ae ECX: 00000006 EDX: 00000000
[   26.986123][   T76] ESI: f81b52af EDI: 00000000 EBP: efd25a8c ESP: efd25a84
[   26.987548][   T76] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068 EFLAGS: 00210282
[   26.989110][   T76] CR0: 80050033 CR2: 00000000 CR3: 6fcc2000 CR4: 000406d0
[   26.990542][   T76] Call Trace:
[   26.991231][   T76]  ddebug_condense_sites (dynamic_debug.c:1633)
[   26.992296][   T76]  ? ddebug_add_module (dynamic_debug.c:1690)
[   26.993328][   T76]  ddebug_add_module (dynamic_debug.c:?)
[   26.994609][   T76]  ? __this_cpu_preempt_check (smp_processor_id.c:65)
[   26.996249][   T76]  ? lock_acquire (locking/lockdep.c:470 (discriminator 3))
[   26.997621][   T76]  ddebug_module_notify (dynamic_debug.c:1888)
[   26.999124][   T76]  ? __mutex_lock_common (x86/include/asm/preempt.h:104 locking/mutex.c:656)
[   27.000830][   T76]  ? __this_cpu_preempt_check (smp_processor_id.c:65)
[   27.002451][   T76]  ? lock_release (locking/lockdep.c:470 (discriminator 3))
[   27.003857][   T76]  ? kprobes_module_callback (kprobes.c:2709)
[   27.005572][   T76]  ? __mutex_unlock_slowpath (x86/include/asm/atomic.h:23 linux/atomic/atomic-arch-fallback.h:457 linux/atomic/atomic-long.h:40 linux/atomic/atomic-instrumented.h:3189 locking/mutex.c:999)
[   27.007240][   T76]  ? mutex_unlock (locking/mutex.c:583)
[   27.008698][   T76]  ? kprobes_module_callback (kprobes.c:2709)
[   27.010393][   T76]  notifier_call_chain (notifier.c:85)
[   27.011917][   T76]  blocking_notifier_call_chain_robust (notifier.c:120 notifier.c:345)
[   27.013788][   T76]  load_module (module/main.c:3363)
[   27.015193][   T76]  __ia32_sys_finit_module (module/main.c:3783 module/main.c:3795 module/main.c:3821 module/main.c:3805 module/main.c:3805)
[   27.016794][   T76]  ia32_sys_call (x86/entry/syscall_32.c:50 (discriminator 201719808))
[   27.018186][   T76]  do_int80_syscall_32 (x86/entry/syscall_32.c:?)
[   27.019830][   T76]  ? do_int80_syscall_32 (x86/include/asm/irqflags.h:42 x86/include/asm/irqflags.h:119 linux/entry-common.h:177 x86/entry/syscall_32.c:255)
[   27.021392][   T76]  ? __this_cpu_preempt_check (smp_processor_id.c:65)
[   27.022979][   T76]  ? lockdep_hardirqs_on (locking/lockdep.c:4472 (discriminator 5))
[   27.024765][   T76]  ? do_int80_syscall_32 (x86/include/asm/irqflags.h:42 x86/include/asm/irqflags.h:119 linux/entry-common.h:177 x86/entry/syscall_32.c:255)
[   27.026351][   T76]  ? entry_INT80_32 (x86/entry/entry_32.S:942)
[   27.027829][   T76]  ? trace_hardirqs_on (trace/trace_preemptirq.c:80)
[   27.029336][   T76]  ? do_int80_syscall_32 (x86/include/asm/preempt.h:104 linux/randomize_kstack.h:58 x86/entry/syscall_32.c:258)
[   27.030991][   T76]  ? entry_INT80_32 (x86/entry/entry_32.S:942)
[   27.032493][   T76]  entry_INT80_32 (x86/entry/entry_32.S:942)
[   27.033493][   T76] EIP: 0x77f27092
[   27.034250][   T76] Code: 00 00 00 e9 90 ff ff ff ff a3 24 00 00 00 68 30 00 00 00 e9 80 ff ff ff ff a3 f8 ff ff ff 66 90 00 00 00 00 00 00 00 00 cd 80 <c3> 8d b4 26 00 00 00 00 8d b6 00 00 00 00 8b 1c 24 c3 8d b4 26 00
All code
========
   0:	00 00                	add    %al,(%rax)
   2:	00 e9                	add    %ch,%cl
   4:	90                   	nop
   5:	ff                   	(bad)
   6:	ff                   	(bad)
   7:	ff                   	(bad)
   8:	ff a3 24 00 00 00    	jmp    *0x24(%rbx)
   e:	68 30 00 00 00       	push   $0x30
  13:	e9 80 ff ff ff       	jmp    0xffffffffffffff98
  18:	ff a3 f8 ff ff ff    	jmp    *-0x8(%rbx)
  1e:	66 90                	xchg   %ax,%ax
	...
  28:	cd 80                	int    $0x80
  2a:*	c3                   	ret		<-- trapping instruction
  2b:	8d b4 26 00 00 00 00 	lea    0x0(%rsi,%riz,1),%esi
  32:	8d b6 00 00 00 00    	lea    0x0(%rsi),%esi
  38:	8b 1c 24             	mov    (%rsp),%ebx
  3b:	c3                   	ret
  3c:	8d                   	.byte 0x8d
  3d:	b4 26                	mov    $0x26,%ah
	...

Code starting with the faulting instruction
===========================================
   0:	c3                   	ret
   1:	8d b4 26 00 00 00 00 	lea    0x0(%rsi,%riz,1),%esi
   8:	8d b6 00 00 00 00    	lea    0x0(%rsi),%esi
   e:	8b 1c 24             	mov    (%rsp),%ebx
  11:	c3                   	ret
  12:	8d                   	.byte 0x8d
  13:	b4 26                	mov    $0x26,%ah


The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20260615/202606152239.7c9bee0c-lkp@intel.com



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


                 reply	other threads:[~2026-06-15 14:16 UTC|newest]

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