[syzbot] [usb?] general protection fault in count_matching_names (2)

[syzbot <syzbot+27c198c3fe6ec83bf701@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    0b2f041c47ac Add linux-next specific files for 20251009
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1136c542580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d4057daadbd2196b
dashboard link: https://syzkaller.appspot.com/bug?extid=27c198c3fe6ec83bf701
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10a54b34580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7457234c80b4/disk-0b2f041c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0b9bc009e937/vmlinux-0b2f041c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/81911ba26337/bzImage-0b2f041c.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+27c198c3fe6ec83bf701@syzkaller.appspotmail.com

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000060: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000300-0x0000000000000307]
CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:strcmp+0x3c/0xc0 lib/string.c:284
Code: 00 fc ff df 45 31 f6 4a 8d 04 37 48 89 c1 48 c1 e9 03 0f b6 0c 19 84 c9 75 2c 42 0f b6 2c 37 4a 8d 04 36 48 89 c1 48 c1 e9 03 <0f> b6 0c 19 84 c9 75 33 42 0f b6 0c 36 40 38 cd 75 48 49 ff c6 40
RSP: 0018:ffffc90000007700 EFLAGS: 00010006
RAX: 0000000000000300 RBX: dffffc0000000000 RCX: 0000000000000060
RDX: 0000000000000001 RSI: 0000000000000300 RDI: ffffffff8bc0d800
RBP: 0000000000000026 R08: 0000000000000001 R09: 0000000000000001
R10: dffffc0000000000 R11: ffffed10048b6802 R12: ffffffff933b4400
R13: ffffffff96182098 R14: 0000000000000000 R15: ffffffff93380340
FS:  0000000000000000(0000) GS:ffff888125d2b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1dd8518750 CR3: 0000000078662000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 count_matching_names+0x57/0x90 kernel/locking/lockdep.c:878
 register_lock_class+0x23f/0x320 kernel/locking/lockdep.c:1344
 __lock_acquire+0x99/0xd20 kernel/locking/lockdep.c:5112
 lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
 complete_with_flags kernel/sched/completion.c:25 [inline]
 complete+0x28/0x1b0 kernel/sched/completion.c:52
 transfer drivers/usb/gadget/udc/dummy_hcd.c:1523 [inline]
 dummy_timer+0x214f/0x44c0 drivers/usb/gadget/udc/dummy_hcd.c:1979
 __run_hrtimer kernel/time/hrtimer.c:1777 [inline]
 __hrtimer_run_queues+0x52c/0xc60 kernel/time/hrtimer.c:1841
 hrtimer_run_softirq+0x187/0x2b0 kernel/time/hrtimer.c:1858
 handle_softirqs+0x286/0x870 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 invoke_softirq kernel/softirq.c:496 [inline]
 __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:723
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1052
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:finish_task_switch+0x26b/0x950 kernel/sched/core.c:5193
Code: 0f 84 3c 01 00 00 48 85 db 0f 85 63 01 00 00 0f 1f 44 00 00 4c 8b 75 d0 4c 89 e7 e8 ef fb b5 09 e8 aa a9 36 00 fb 4c 8b 65 c0 <49> 8d bc 24 58 16 00 00 48 89 f8 48 c1 e8 03 42 0f b6 04 28 84 c0
RSP: 0018:ffffffff8de07af8 EFLAGS: 00000282
RAX: 3132a480b5f71400 RBX: 0000000000000000 RCX: 3132a480b5f71400
RDX: 0000000000000000 RSI: ffffffff8d7f1156 RDI: ffffffff8bc0d160
RBP: ffffffff8de07b50 R08: ffffffff8f9dba77 R09: 1ffffffff1f3b74e
R10: dffffc0000000000 R11: fffffbfff1f3b74f R12: ffffffff8de95200
R13: dffffc0000000000 R14: ffff888030a18000 R15: ffff8880b863abd8
 context_switch kernel/sched/core.c:5328 [inline]
 __schedule+0x17a0/0x4cc0 kernel/sched/core.c:6929
 schedule_idle+0x52/0x90 kernel/sched/core.c:7052
 do_idle+0x4a7/0x510 kernel/sched/idle.c:358
 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428
 rest_init+0x2de/0x300 init/main.c:757
 start_kernel+0x3ae/0x410 init/main.c:1111
 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310
 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291
 common_startup_64+0x13e/0x147
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:strcmp+0x3c/0xc0 lib/string.c:284
Code: 00 fc ff df 45 31 f6 4a 8d 04 37 48 89 c1 48 c1 e9 03 0f b6 0c 19 84 c9 75 2c 42 0f b6 2c 37 4a 8d 04 36 48 89 c1 48 c1 e9 03 <0f> b6 0c 19 84 c9 75 33 42 0f b6 0c 36 40 38 cd 75 48 49 ff c6 40
RSP: 0018:ffffc90000007700 EFLAGS: 00010006
RAX: 0000000000000300 RBX: dffffc0000000000 RCX: 0000000000000060
RDX: 0000000000000001 RSI: 0000000000000300 RDI: ffffffff8bc0d800
RBP: 0000000000000026 R08: 0000000000000001 R09: 0000000000000001
R10: dffffc0000000000 R11: ffffed10048b6802 R12: ffffffff933b4400
R13: ffffffff96182098 R14: 0000000000000000 R15: ffffffff93380340
FS:  0000000000000000(0000) GS:ffff888125d2b000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f1dd8518750 CR3: 0000000078662000 CR4: 00000000003526f0
----------------
Code disassembly (best guess), 4 bytes skipped:
   0:	45 31 f6             	xor    %r14d,%r14d
   3:	4a 8d 04 37          	lea    (%rdi,%r14,1),%rax
   7:	48 89 c1             	mov    %rax,%rcx
   a:	48 c1 e9 03          	shr    $0x3,%rcx
   e:	0f b6 0c 19          	movzbl (%rcx,%rbx,1),%ecx
  12:	84 c9                	test   %cl,%cl
  14:	75 2c                	jne    0x42
  16:	42 0f b6 2c 37       	movzbl (%rdi,%r14,1),%ebp
  1b:	4a 8d 04 36          	lea    (%rsi,%r14,1),%rax
  1f:	48 89 c1             	mov    %rax,%rcx
  22:	48 c1 e9 03          	shr    $0x3,%rcx
* 26:	0f b6 0c 19          	movzbl (%rcx,%rbx,1),%ecx <-- trapping instruction
  2a:	84 c9                	test   %cl,%cl
  2c:	75 33                	jne    0x61
  2e:	42 0f b6 0c 36       	movzbl (%rsi,%r14,1),%ecx
  33:	40 38 cd             	cmp    %cl,%bpl
  36:	75 48                	jne    0x80
  38:	49 ff c6             	inc    %r14
  3b:	40                   	rex


---
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