general protection fault, probably for non-canonical address 0xdffffc0000000009: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000048-0x000000000000004f]
CPU: 0 PID: 6188 Comm: syz.1.75 Not tainted 6.6.102-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:loopback_jiffies_timer_pos_update+0x13c/0x1250 sound/drivers/aloop.c:619
Code: fb 49 f9 44 89 f8 83 e0 02 44 89 7c 24 3c 75 0a e8 79 f7 49 f9 45 31 ff eb 27 e8 6f f7 49 f9 49 8d 5d 48 48 89 d8 48 c1 e8 03 <80> 3c 28 00 74 08 48 89 df e8 86 3e a1 f9 4d 89 f7 4c 2b 3b 4c 89
RSP: 0018:ffffc90003437568 EFLAGS: 00010006
RAX: 0000000000000009 RBX: 0000000000000048 RCX: ffff88802ae83c00
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000000
RBP: dffffc0000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000686eb0 R12: 000000000000002e
R13: 0000000000000000 R14: 00000000ffffbcfc R15: 0000000000000003
FS:  000055559051c500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000032000 CR3: 000000002ed4e000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 loopback_pointer+0xf8/0x1a0 sound/drivers/aloop.c:871
 snd_pcm_update_hw_ptr0+0x178/0x1a40 sound/core/pcm_lib.c:304
 snd_pcm_update_hw_ptr sound/core/pcm_lib.c:496 [inline]
 __snd_pcm_lib_xfer+0x50f/0x1c40 sound/core/pcm_lib.c:2262
 snd_pcm_oss_write3+0x1bc/0x320 sound/core/oss/pcm_oss.c:1252
 snd_pcm_plug_write_transfer+0x2b8/0x4a0 sound/core/oss/pcm_plugin.c:630
 snd_pcm_oss_write2 sound/core/oss/pcm_oss.c:1384 [inline]
 snd_pcm_oss_sync1+0x285/0x6e0 sound/core/oss/pcm_oss.c:1626
 snd_pcm_oss_sync+0x7d4/0xc20 sound/core/oss/pcm_oss.c:1692
 snd_pcm_oss_release+0x102/0x240 sound/core/oss/pcm_oss.c:2589
 __fput+0x234/0x970 fs/file_table.c:384
 task_work_run+0x1ce/0x250 kernel/task_work.c:239
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f6ca478ebe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd83720538 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 00007f6ca49b7da0 RCX: 00007f6ca478ebe9
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007f6ca49b7da0 R08: 0000000000000000 R09: 0000000b8372082f
R10: 000000000003fd74 R11: 0000000000000246 R12: 00000000000206c0
R13: 00007ffd83720630 R14: ffffffffffffffff R15: 00007ffd83720650
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:loopback_jiffies_timer_pos_update+0x13c/0x1250 sound/drivers/aloop.c:619
Code: fb 49 f9 44 89 f8 83 e0 02 44 89 7c 24 3c 75 0a e8 79 f7 49 f9 45 31 ff eb 27 e8 6f f7 49 f9 49 8d 5d 48 48 89 d8 48 c1 e8 03 <80> 3c 28 00 74 08 48 89 df e8 86 3e a1 f9 4d 89 f7 4c 2b 3b 4c 89
RSP: 0018:ffffc90003437568 EFLAGS: 00010006
RAX: 0000000000000009 RBX: 0000000000000048 RCX: ffff88802ae83c00
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000000
RBP: dffffc0000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000686eb0 R12: 000000000000002e
R13: 0000000000000000 R14: 00000000ffffbcfc R15: 0000000000000003
FS:  000055559051c500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000032000 CR3: 000000002ed4e000 CR4: 00000000003506f0
----------------
Code disassembly (best guess):
   0:	fb                   	sti
   1:	49 f9                	rex.WB stc
   3:	44 89 f8             	mov    %r15d,%eax
   6:	83 e0 02             	and    $0x2,%eax
   9:	44 89 7c 24 3c       	mov    %r15d,0x3c(%rsp)
   e:	75 0a                	jne    0x1a
  10:	e8 79 f7 49 f9       	call   0xf949f78e
  15:	45 31 ff             	xor    %r15d,%r15d
  18:	eb 27                	jmp    0x41
  1a:	e8 6f f7 49 f9       	call   0xf949f78e
  1f:	49 8d 5d 48          	lea    0x48(%r13),%rbx
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	80 3c 28 00          	cmpb   $0x0,(%rax,%rbp,1) <-- trapping instruction
  2e:	74 08                	je     0x38
  30:	48 89 df             	mov    %rbx,%rdi
  33:	e8 86 3e a1 f9       	call   0xf9a13ebe
  38:	4d 89 f7             	mov    %r14,%r15
  3b:	4c 2b 3b             	sub    (%rbx),%r15
  3e:	4c                   	rex.WR
  3f:	89                   	.byte 0x89