Dear Linux folks,


Unfortunately, not reproducible, but starting with Linux 6.18-rc7, I got 
the oops below *once*:

```
Linux version 6.18.0-rc7 (build@bohemianrhapsody.molgen.mpg.de) (gcc 
(Debian 15.2.0-8) 15.2.0, GNU ld (GNU Binutils for Debian) 2.45) #162 
SMP PREEMPT_DYNAMIC Mon Nov 24 09:54:29 CET 2025
Command line: BOOT_IMAGE=/vmlinuz-6.18.0-rc7 
root=UUID=32e29882-d94d-4a92-9ee4-4d03002bfa29 ro quiet pci=noaer 
mem_sleep_default=deep log_buf_len=16M cryptomgr.notests 
usbcore.quirks=0cf3:e300:e,04f3:2234:e,0c45:670c:e
[…]
ACPI: bus type drm_connector registered
BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 0 P4D 0
Oops: Oops: 0010 [#1] SMP
CPU: 2 UID: 0 PID: 352 Comm: systemd-modules Not tainted 6.18.0-rc7 #162 
PREEMPT(voluntary)
Hardware name: Dell Inc. XPS 13 9360/0596KF, BIOS 2.21.0 06/02/2022
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffad3fc09039b0 EFLAGS: 00010286
RAX: ffff96f5c4cce3c0 RBX: ffff96f610558000 RCX: 0000000000000007
RDX: ffffffffc07935c0 RSI: ffff96f5c4d77d60 RDI: ffff96f61095cc00
RBP: ffffad3fc0903a00 R08: 00000000fffffff3 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff977c1300 R12: ffff96f610558040
R13: ffff96f61095cc50 R14: ffff96f61095cc00 R15: ffff96f5c1f149e8
FS:  00007ffb00dff6c0(0000) GS:ffff96f995987000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000103aa8005 CR4: 00000000003706f0
Call Trace:
  <TASK>
  parport_register_dev_model+0x273/0x3c0 [parport]
  lp_register+0x6f/0x100 [lp]
  ? parport_default_proc_unregister+0x490/0x490 [parport]
  ? parport_irq_handler+0x50/0x50 [parport]
  lp_attach+0x99/0xc0 [lp]
  port_check+0x1d/0x20 [parport]
  bus_for_each_dev+0x82/0xd0
  ? dell_wmi_exit+0x580/0x580 [dell_wmi]
  __parport_register_driver+0x7e/0xb0 [parport]
  lp_init_module+0x1e2/0x1000 [lp]
  do_one_initcall+0x58/0x2f0
  do_init_module+0x67/0x2a0
  init_module_from_file+0x85/0xc0
  __x64_sys_finit_module+0x163/0x3d0
  do_syscall_64+0x82/0x9b0
  ? vfs_read+0x15e/0x380
  ? vfs_read+0x15e/0x380
  ? __rseq_handle_notify_resume+0xa6/0x480
  ? restore_fpregs_from_fpstate+0x46/0xa0
  ? switch_fpu_return+0x5b/0xd0
  ? do_syscall_64+0x21d/0x9b0
  ? exc_page_fault+0x7e/0x1a0
  entry_SYSCALL_64_after_hwframe+0x4b/0x53
RIP: 0033:0x7ffb01718779
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 
f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 
f0 ff ff 73 01 c3 48 8b 0d 4f 86 0d 00 f7 d8 64 89 01 48
RSP: 002b:00007ffb00dfdbe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
RAX: ffffffffffffffda RBX: 00007ffaf8002380 RCX: 00007ffb01718779
RDX: 0000000000000000 RSI: 00007ffb01e8444d RDI: 0000000000000009
RBP: 0000000000000000 R08: 0000000000000000 R09: 00007ffaf80039d0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffb01e8444d
R13: 0000000000020000 R14: 00007ffaf80024a0 R15: 0000000000000000
  </TASK>
Modules linked in: ppdev(+) parport_pc(+) lp(+) msr(+) parport drm 
efi_pstore configfs nfnetlink efivarfs autofs4 ext4 crc16 mbcache jbd2 
dm_crypt dm_mod dell_wmi dell_smbios dell_wmi_descriptor evdev dcdbas 
serio_raw pcspkr nvme nvme_core video wmi intel_hid sparse_keymap 
aesni_intel
CR2: 0000000000000000
---[ end trace 0000000000000000 ]---
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffad3fc09039b0 EFLAGS: 00010286
RAX: ffff96f5c4cce3c0 RBX: ffff96f610558000 RCX: 0000000000000007
RDX: ffffffffc07935c0 RSI: ffff96f5c4d77d60 RDI: ffff96f61095cc00
RBP: ffffad3fc0903a00 R08: 00000000fffffff3 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff977c1300 R12: ffff96f610558040
R13: ffff96f61095cc50 R14: ffff96f61095cc00 R15: ffff96f5c1f149e8
FS:  00007ffb00dff6c0(0000) GS:ffff96f995987000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000103aa8005 CR4: 00000000003706f0
```

Please find the output of `journalctl -o short-monotonic -b -1 
_TRANSPORT=kernel` with the systemd entries and systemd messages removed 
attached.

I guess parport is a red hering, but I am not sure, but I am adding the 
memory folks just in case.


Kind regards,

Paul


PS: Result of

     $ scripts/decode_stacktrace.sh arch/x86_64/boot/bzImage auto 
./debian/linux-image-6.18.0-rc7-dbg/usr/lib/debug/lib/modules/6.18.0-rc7/ 
< 20251126--linux-6.18-rc7--messages--oops-parport_register_dev_model.txt

in the build directory on the build host:

```
[   27.085475] BUG: kernel NULL pointer dereference, address: 
0000000000000000
[   27.085491] #PF: supervisor instruction fetch in kernel mode
[   27.085505] #PF: error_code(0x0010) - not-present page
[   27.085519] PGD 0 P4D 0
[   27.085534] Oops: Oops: 0010 [#1] SMP
[   27.085547] CPU: 2 UID: 0 PID: 352 Comm: systemd-modules Not tainted 
6.18.0-rc7 #162 PREEMPT(voluntary)
[   27.085563] Hardware name: Dell Inc. XPS 13 9360/0596KF, BIOS 2.21.0 
06/02/2022
[   27.085576] RIP: 0010:0x0
[   27.085589] Code: Unable to access opcode bytes at 0xffffffffffffffd6.

Code starting with the faulting instruction
===========================================
[   27.085604] RSP: 0018:ffffad3fc09039b0 EFLAGS: 00010286
[   27.085621] RAX: ffff96f5c4cce3c0 RBX: ffff96f610558000 RCX: 
0000000000000007
[   27.085635] RDX: ffffffffc07935c0 RSI: ffff96f5c4d77d60 RDI: 
ffff96f61095cc00
[   27.085649] RBP: ffffad3fc0903a00 R08: 00000000fffffff3 R09: 
0000000000000000
[   27.085662] R10: 0000000000000000 R11: ffffffff977c1300 R12: 
ffff96f610558040
[   27.085676] R13: ffff96f61095cc50 R14: ffff96f61095cc00 R15: 
ffff96f5c1f149e8
[   27.085692] FS:  00007ffb00dff6c0(0000) GS:ffff96f995987000(0000) 
knlGS:0000000000000000
[   27.085706] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   27.085720] CR2: ffffffffffffffd6 CR3: 0000000103aa8005 CR4: 
00000000003706f0
[   27.085733] Call Trace:
[   27.085746]  <TASK>
[   27.085759] parport_register_dev_model 
(/home/build/src/linux/./arch/x86/include/asm/bitops.h:136 
(discriminator 1) 
/home/build/src/linux/./include/asm-generic/bitops/instrumented-atomic.h:72 
(discriminator 1) /home/build/src/linux/drivers/parport/share.c:790 
(discriminator 1)) parport
[   27.085773] lp_register (/home/build/src/linux/drivers/char/lp.c:928 
(discriminator 1)) lp
[   27.085787]  ? parport_default_proc_unregister 
(/home/build/src/linux/drivers/parport/share.c:1003) parport
[   27.085802]  ? parport_irq_handler 
(/home/build/src/linux/drivers/parport/share.c:215) parport
[   27.085818] lp_attach (/home/build/src/linux/drivers/char/lp.c:977 
(discriminator 1)) lp
[   27.085831] port_check 
(/home/build/src/linux/drivers/parport/share.c:222) parport
[   27.085845]  bus_for_each_dev+0x82/0xd0
[   27.085858]  ? dell_wmi_exit 
(/home/build/src/linux/drivers/platform/x86/dell/dell-wmi-base.c:696 
/home/build/src/linux/drivers/platform/x86/dell/dell-wmi-base.c:810 
/home/build/src/linux/drivers/platform/x86/dell/dell-wmi-base.c:792) 
dell_wmi
[   27.085872] __parport_register_driver 
(/home/build/src/linux/drivers/parport/share.c:297 
/home/build/src/linux/drivers/parport/share.c:269) parport
[   27.085886] lp_init_module 
(/home/build/src/linux/drivers/char/lp.c:213) lp
[   27.085900]  do_one_initcall+0x58/0x2f0
[   27.085913]  do_init_module+0x67/0x2a0
[   27.085927]  init_module_from_file+0x85/0xc0
[   27.085943]  __x64_sys_finit_module+0x163/0x3d0
[   27.085957]  do_syscall_64+0x82/0x9b0
[   27.085970]  ? vfs_read+0x15e/0x380
[   27.085984]  ? vfs_read+0x15e/0x380
[   27.085998]  ? __rseq_handle_notify_resume+0xa6/0x480
[   27.086012]  ? restore_fpregs_from_fpstate+0x46/0xa0
[   27.086025]  ? switch_fpu_return+0x5b/0xd0
[   27.086038]  ? do_syscall_64+0x21d/0x9b0
[   27.086054]  ? exc_page_fault+0x7e/0x1a0
[   27.086068]  entry_SYSCALL_64_after_hwframe+0x4b/0x53
[   27.086081] RIP: 0033:0x7ffb01718779
[   27.086095] Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 
48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 
05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 4f 86 0d 00 f7 d8 64 89 01 48
All code
========
    0:	ff c3                	inc    %ebx
    2:	66 2e 0f 1f 84 00 00 	cs nopw 0x0(%rax,%rax,1)
    9:	00 00 00
    c:	0f 1f 44 00 00       	nopl   0x0(%rax,%rax,1)
   11:	48 89 f8             	mov    %rdi,%rax
   14:	48 89 f7             	mov    %rsi,%rdi
   17:	48 89 d6             	mov    %rdx,%rsi
   1a:	48 89 ca             	mov    %rcx,%rdx
   1d:	4d 89 c2             	mov    %r8,%r10
   20:	4d 89 c8             	mov    %r9,%r8
   23:	4c 8b 4c 24 08       	mov    0x8(%rsp),%r9
   28:	0f 05                	syscall
   2a:*	48 3d 01 f0 ff ff    	cmp    $0xfffffffffffff001,%rax		<-- 
trapping instruction
   30:	73 01                	jae    0x33
   32:	c3                   	ret
   33:	48 8b 0d 4f 86 0d 00 	mov    0xd864f(%rip),%rcx        # 0xd8689
   3a:	f7 d8                	neg    %eax
   3c:	64 89 01             	mov    %eax,%fs:(%rcx)
   3f:	48                   	rex.W

Code starting with the faulting instruction
===========================================
    0:	48 3d 01 f0 ff ff    	cmp    $0xfffffffffffff001,%rax
    6:	73 01                	jae    0x9
    8:	c3                   	ret
    9:	48 8b 0d 4f 86 0d 00 	mov    0xd864f(%rip),%rcx        # 0xd865f
   10:	f7 d8                	neg    %eax
   12:	64 89 01             	mov    %eax,%fs:(%rcx)
   15:	48                   	rex.W
[   27.086108] RSP: 002b:00007ffb00dfdbe8 EFLAGS: 00000246 ORIG_RAX: 
0000000000000139
[   27.086123] RAX: ffffffffffffffda RBX: 00007ffaf8002380 RCX: 
00007ffb01718779
[   27.086137] RDX: 0000000000000000 RSI: 00007ffb01e8444d RDI: 
0000000000000009
[   27.086151] RBP: 0000000000000000 R08: 0000000000000000 R09: 
00007ffaf80039d0
[   27.086164] R10: 0000000000000000 R11: 0000000000000246 R12: 
00007ffb01e8444d
[   27.086180] R13: 0000000000020000 R14: 00007ffaf80024a0 R15: 
0000000000000000
[   27.086194]  </TASK>
[   27.086209] Modules linked in: ppdev(+) parport_pc(+) lp(+) msr(+) 
parport drm efi_pstore configfs nfnetlink efivarfs autofs4 ext4 crc16 
mbcache jbd2 dm_crypt dm_mod dell_wmi dell_smbios dell_wmi_descriptor 
evdev dcdbas serio_raw pcspkr nvme nvme_core video wmi intel_hid 
sparse_keymap aesni_intel
[   27.086239] CR2: 0000000000000000
[   27.086253] ---[ end trace 0000000000000000 ]---
[   27.086281] RIP: 0010:0x0
[   27.086296] Code: Unable to access opcode bytes at 0xffffffffffffffd6.

Code starting with the faulting instruction
===========================================
[   27.086311] RSP: 0018:ffffad3fc09039b0 EFLAGS: 00010286
[   27.086324] RAX: ffff96f5c4cce3c0 RBX: ffff96f610558000 RCX: 
0000000000000007
[   27.086337] RDX: ffffffffc07935c0 RSI: ffff96f5c4d77d60 RDI: 
ffff96f61095cc00
[   27.086353] RBP: ffffad3fc0903a00 R08: 00000000fffffff3 R09: 
0000000000000000
[   27.086366] R10: 0000000000000000 R11: ffffffff977c1300 R12: 
ffff96f610558040
[   27.086379] R13: ffff96f61095cc50 R14: ffff96f61095cc00 R15: 
ffff96f5c1f149e8
[   27.086392] FS:  00007ffb00dff6c0(0000) GS:ffff96f995987000(0000) 
knlGS:0000000000000000
[   27.086405] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   27.086418] CR2: ffffffffffffffd6 CR3: 0000000103aa8005 CR4: 
00000000003706f0
[   27.086431] note: systemd-modules[352] exited with irqs disabled
[   27.086464] EXT4-fs (dm-0): re-mounted 
32e29882-d94d-4a92-9ee4-4d03002bfa29 r/w.
```