Oops: general protection fault, probably for non-canonical address 0xdffffc00000000ac: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000560-0x0000000000000567]
CPU: 1 UID: 0 PID: 12937 Comm: syz.4.1505 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:atmtcp_recv_control drivers/atm/atmtcp.c:93 [inline]
RIP: 0010:atmtcp_c_send+0x673/0xb30 drivers/atm/atmtcp.c:297
Code: 01 38 d0 7c 08 84 d2 0f 85 da 03 00 00 48 8d bd 60 05 00 00 44 0f b7 63 1a 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 01 0f 8e a3 03 00 00 48 8d 7b 1c 66 44
RSP: 0018:ffffc9001e5df980 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: ffff888057e7d6c0 RCX: ffffc9000d00a000
RDX: 00000000000000ac RSI: ffffffff872e6895 RDI: 0000000000000560
RBP: 0000000000000000 R08: 0000000000000005 R09: 00000000ffffffff
R10: 00000000ffffffff R11: 0000000000000001 R12: 0000000000000000
R13: ffff888074fec29c R14: ffff888030535500 R15: ffff888030535500
FS:  00007fac20cb06c0(0000) GS:ffff8881247b9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000000129c CR3: 0000000057f4d000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 vcc_sendmsg+0x7b2/0xf70 net/atm/common.c:645
 sock_sendmsg_nosec net/socket.c:714 [inline]
 __sock_sendmsg net/socket.c:729 [inline]
 ____sys_sendmsg+0xa98/0xc70 net/socket.c:2614
 ___sys_sendmsg+0x134/0x1d0 net/socket.c:2668
 __sys_sendmsg+0x16d/0x220 net/socket.c:2700
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fac1fd8ebe9
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:00007fac20cb0038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fac1ffb5fa0 RCX: 00007fac1fd8ebe9
RDX: 0000000004040800 RSI: 0000200000000140 RDI: 0000000000000004
RBP: 00007fac1fe11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fac1ffb6038 R14: 00007fac1ffb5fa0 R15: 00007ffe85f7bcb8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:atmtcp_recv_control drivers/atm/atmtcp.c:93 [inline]
RIP: 0010:atmtcp_c_send+0x673/0xb30 drivers/atm/atmtcp.c:297
Code: 01 38 d0 7c 08 84 d2 0f 85 da 03 00 00 48 8d bd 60 05 00 00 44 0f b7 63 1a 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 01 0f 8e a3 03 00 00 48 8d 7b 1c 66 44
RSP: 0018:ffffc9001e5df980 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: ffff888057e7d6c0 RCX: ffffc9000d00a000
RDX: 00000000000000ac RSI: ffffffff872e6895 RDI: 0000000000000560
RBP: 0000000000000000 R08: 0000000000000005 R09: 00000000ffffffff
R10: 00000000ffffffff R11: 0000000000000001 R12: 0000000000000000
R13: ffff888074fec29c R14: ffff888030535500 R15: ffff888030535500
FS:  00007fac20cb06c0(0000) GS:ffff8881247b9000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffdb6176f08 CR3: 0000000057f4d000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	01 38                	add    %edi,(%rax)
   2:	d0 7c 08 84          	sarb   -0x7c(%rax,%rcx,1)
   6:	d2 0f                	rorb   %cl,(%rdi)
   8:	85 da                	test   %ebx,%edx
   a:	03 00                	add    (%rax),%eax
   c:	00 48 8d             	add    %cl,-0x73(%rax)
   f:	bd 60 05 00 00       	mov    $0x560,%ebp
  14:	44 0f b7 63 1a       	movzwl 0x1a(%rbx),%r12d
  19:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  20:	fc ff df
  23:	48 89 fa             	mov    %rdi,%rdx
  26:	48 c1 ea 03          	shr    $0x3,%rdx
* 2a:	0f b6 04 02          	movzbl (%rdx,%rax,1),%eax <-- trapping instruction
  2e:	84 c0                	test   %al,%al
  30:	74 08                	je     0x3a
  32:	3c 01                	cmp    $0x1,%al
  34:	0f 8e a3 03 00 00    	jle    0x3dd
  3a:	48 8d 7b 1c          	lea    0x1c(%rbx),%rdi
  3e:	66                   	data16
  3f:	44                   	rex.R