Oops: general protection fault, probably for non-canonical address 0xdffffc0000000060: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000300-0x0000000000000307]
CPU: 1 UID: 0 PID: 12584 Comm: syz.3.1588 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:strcmp+0x5b/0xb0 lib/string.c:284
Code: fa 48 c1 e8 03 83 e2 07 42 0f b6 04 28 38 d0 7f 04 84 c0 75 58 48 89 f0 48 89 f2 0f b6 6b ff 4c 8d 66 01 48 c1 e8 03 83 e2 07 <42> 0f b6 04 28 38 d0 7f 04 84 c0 75 2c 41 3a 6c 24 ff 74 ae 19 c0
RSP: 0018:ffffc900001a89d0 EFLAGS: 00010046
RAX: 0000000000000060 RBX: ffffffff87afe081 RCX: ffffffff8f0100e0
RDX: 0000000000000000 RSI: 0000000000000300 RDI: ffffffff87afe080
RBP: 0000000000000026 R08: 0000000000000001 R09: 0000000000000000
R10: ffff88810b324020 R11: 0000000000000001 R12: 0000000000000301
R13: dffffc0000000000 R14: 0000000000000a6a R15: ffffffff8efd4888
FS:  0000000000000000(0000) GS:ffff8882687c9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff1679f1000 CR3: 0000000123c0c000 CR4: 00000000003506f0
Call Trace:
 <IRQ>
 count_matching_names kernel/locking/lockdep.c:878 [inline]
 register_lock_class+0x2cb/0x560 kernel/locking/lockdep.c:1344
 __lock_acquire+0x3cb/0x2630 kernel/locking/lockdep.c:5112
 lock_acquire kernel/locking/lockdep.c:5868 [inline]
 lock_acquire+0x1cf/0x380 kernel/locking/lockdep.c:5825
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
 _raw_spin_lock_irqsave+0x3a/0x60 kernel/locking/spinlock.c:162
 complete_with_flags kernel/sched/completion.c:25 [inline]
 complete+0x1d/0x200 kernel/sched/completion.c:52
 transfer drivers/usb/gadget/udc/dummy_hcd.c:1527 [inline]
 dummy_timer+0x121c/0x36c0 drivers/usb/gadget/udc/dummy_hcd.c:1989
 __run_hrtimer kernel/time/hrtimer.c:1785 [inline]
 __hrtimer_run_queues+0x50e/0xa70 kernel/time/hrtimer.c:1849
 hrtimer_run_softirq+0x17d/0x350 kernel/time/hrtimer.c:1866
 handle_softirqs+0x1de/0x9d0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0xed/0x150 kernel/softirq.c:723
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline]
 sysvec_apic_timer_interrupt+0x8f/0xb0 arch/x86/kernel/apic/apic.c:1056
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x5e/0x380 kernel/locking/lockdep.c:5872
Code: 05 3b 98 66 0b 83 f8 07 0f 87 f0 00 00 00 48 0f a3 05 c6 47 61 09 0f 82 c2 02 00 00 8b 35 6e 57 61 09 85 f6 0f 85 dd 00 00 00 <48> 8b 44 24 30 65 48 2b 05 dd 97 66 0b 0f 85 02 03 00 00 48 83 c4
RSP: 0018:ffffc90006a2f398 EFLAGS: 00000206
RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000003
RDX: 0000000000000000 RSI: ffffffff89003676 RDI: ffffffff87afd320
RBP: ffffffff896de6a0 R08: 000000002434c51c R09: 000000000000001e
R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000002
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 rcu_read_lock_sched include/linux/rcupdate.h:948 [inline]
 pfn_valid include/linux/mmzone.h:2197 [inline]
 page_table_check_clear+0x67/0x9e0 mm/page_table_check.c:70
 __page_table_check_pte_clear+0xf1/0x100 mm/page_table_check.c:155
 page_table_check_pte_clear include/linux/page_table_check.h:55 [inline]
 ptep_get_and_clear_full arch/x86/include/asm/pgtable.h:1271 [inline]
 get_and_clear_full_ptes include/linux/pgtable.h:846 [inline]
 zap_present_folio_ptes mm/memory.c:1643 [inline]
 zap_present_ptes mm/memory.c:1725 [inline]
 do_zap_pte_range mm/memory.c:1827 [inline]
 zap_pte_range mm/memory.c:1929 [inline]
 zap_pmd_range mm/memory.c:2021 [inline]
 zap_pud_range mm/memory.c:2049 [inline]
 zap_p4d_range mm/memory.c:2070 [inline]
 unmap_page_range+0x2335/0x3cd0 mm/memory.c:2091
 unmap_single_vma+0x153/0x240 mm/memory.c:2133
 unmap_vmas+0x295/0x590 mm/memory.c:2171
 exit_mmap+0x1ef/0xa30 mm/mmap.c:1302
 __mmput kernel/fork.c:1175 [inline]
 mmput+0xe0/0x430 kernel/fork.c:1198
 exit_mm kernel/exit.c:581 [inline]
 do_exit+0x819/0x2b60 kernel/exit.c:964
 do_group_exit+0xd5/0x2a0 kernel/exit.c:1118
 get_signal+0x1ec7/0x21e0 kernel/signal.c:3034
 arch_do_signal_or_restart+0x91/0x7a0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop+0x7e/0x430 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline]
 ret_from_fork+0x6f6/0xcb0 arch/x86/kernel/process.c:167
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:strcmp+0x5b/0xb0 lib/string.c:284
Code: fa 48 c1 e8 03 83 e2 07 42 0f b6 04 28 38 d0 7f 04 84 c0 75 58 48 89 f0 48 89 f2 0f b6 6b ff 4c 8d 66 01 48 c1 e8 03 83 e2 07 <42> 0f b6 04 28 38 d0 7f 04 84 c0 75 2c 41 3a 6c 24 ff 74 ae 19 c0
RSP: 0018:ffffc900001a89d0 EFLAGS: 00010046
RAX: 0000000000000060 RBX: ffffffff87afe081 RCX: ffffffff8f0100e0
RDX: 0000000000000000 RSI: 0000000000000300 RDI: ffffffff87afe080
RBP: 0000000000000026 R08: 0000000000000001 R09: 0000000000000000
R10: ffff88810b324020 R11: 0000000000000001 R12: 0000000000000301
R13: dffffc0000000000 R14: 0000000000000a6a R15: ffffffff8efd4888
FS:  0000000000000000(0000) GS:ffff8882687c9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff1679f1000 CR3: 0000000123c0c000 CR4: 00000000003506f0
----------------
Code disassembly (best guess):
   0:	fa                   	cli
   1:	48 c1 e8 03          	shr    $0x3,%rax
   5:	83 e2 07             	and    $0x7,%edx
   8:	42 0f b6 04 28       	movzbl (%rax,%r13,1),%eax
   d:	38 d0                	cmp    %dl,%al
   f:	7f 04                	jg     0x15
  11:	84 c0                	test   %al,%al
  13:	75 58                	jne    0x6d
  15:	48 89 f0             	mov    %rsi,%rax
  18:	48 89 f2             	mov    %rsi,%rdx
  1b:	0f b6 6b ff          	movzbl -0x1(%rbx),%ebp
  1f:	4c 8d 66 01          	lea    0x1(%rsi),%r12
  23:	48 c1 e8 03          	shr    $0x3,%rax
  27:	83 e2 07             	and    $0x7,%edx
* 2a:	42 0f b6 04 28       	movzbl (%rax,%r13,1),%eax <-- trapping instruction
  2f:	38 d0                	cmp    %dl,%al
  31:	7f 04                	jg     0x37
  33:	84 c0                	test   %al,%al
  35:	75 2c                	jne    0x63
  37:	41 3a 6c 24 ff       	cmp    -0x1(%r12),%bpl
  3c:	74 ae                	je     0xffffffec
  3e:	19 c0                	sbb    %eax,%eax