general protection fault, probably for non-canonical address 0xdffffc000000003d: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x00000000000001e8-0x00000000000001ef]
CPU: 1 PID: 4762 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:xprt_iter_ops net/sunrpc/xprtmultipath.c:218 [inline]
RIP: 0010:xprt_iter_get_next+0xcb/0x2a0 net/sunrpc/xprtmultipath.c:634
Code: c0 b9 a0 8b be 19 03 00 00 48 c7 c2 00 ba a0 8b e8 3a 00 0a f8 49 bc 00 00 00 00 00 fc ff df 4d 8d 7e 10 4c 89 f8 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 ff e8 36 b1 78 f8 4d 8b 3f 4d 85 ff 74
RSP: 0018:ffffc900065ff908 EFLAGS: 00010202
RAX: 000000000000003d RBX: ffffffff895aa8ec RCX: ffff8880184d9e00
RDX: 0000000000000000 RSI: ffffffff8adf5dc0 RDI: ffffffff8adf5d80
RBP: 0000000000000001 R08: dffffc0000000000 R09: 1ffffffff2162048
R10: dffffc0000000000 R11: fffffbfff2162049 R12: dffffc0000000000
R13: dffffc0000000000 R14: 00000000000001d8 R15: 00000000000001e8
FS:  0000555592168500(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcb039f6000 CR3: 000000004971e000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 rpc_task_get_next_xprt net/sunrpc/clnt.c:1139 [inline]
 rpc_task_set_transport+0x149/0x3c0 net/sunrpc/clnt.c:1155
 rpc_task_set_client net/sunrpc/clnt.c:1161 [inline]
 rpc_run_task+0xcd/0x6a0 net/sunrpc/clnt.c:1216
 rpc_call_sync+0x10c/0x1f0 net/sunrpc/clnt.c:1252
 rpcb_register_call net/sunrpc/rpcb_clnt.c:389 [inline]
 rpcb_register+0x2fd/0x5d0 net/sunrpc/rpcb_clnt.c:453
 __svc_unregister net/sunrpc/svc.c:1118 [inline]
 svc_unregister+0x1f9/0x580 net/sunrpc/svc.c:1145
 svc_rpcb_cleanup+0x19/0x30 net/sunrpc/svc.c:407
 nfsd_last_thread+0x100/0x2e0 fs/nfsd/nfssvc.c:560
 nfsd_shutdown_threads+0xd6/0x1a0 fs/nfsd/nfssvc.c:643
 nfsd_umount+0x3e/0xc0 fs/nfsd/nfsctl.c:1409
 deactivate_locked_super+0x93/0xf0 fs/super.c:332
 cleanup_mnt+0x471/0x4f0 fs/namespace.c:1191
 task_work_run+0x1d0/0x260 kernel/task_work.c:203
 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+0xee/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
 do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f508f59f257
Code: a2 c7 05 9c 44 25 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffe54946ed8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f508f59f257
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe54946f90
RBP: 00007ffe54946f90 R08: 00007ffe54947f90 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe54948020
R13: 00007f508f63445c R14: 000000000001cc7e R15: 00007ffe54948060
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:xprt_iter_ops net/sunrpc/xprtmultipath.c:218 [inline]
RIP: 0010:xprt_iter_get_next+0xcb/0x2a0 net/sunrpc/xprtmultipath.c:634
Code: c0 b9 a0 8b be 19 03 00 00 48 c7 c2 00 ba a0 8b e8 3a 00 0a f8 49 bc 00 00 00 00 00 fc ff df 4d 8d 7e 10 4c 89 f8 48 c1 e8 03 <42> 80 3c 20 00 74 08 4c 89 ff e8 36 b1 78 f8 4d 8b 3f 4d 85 ff 74
RSP: 0018:ffffc900065ff908 EFLAGS: 00010202
RAX: 000000000000003d RBX: ffffffff895aa8ec RCX: ffff8880184d9e00
RDX: 0000000000000000 RSI: ffffffff8adf5dc0 RDI: ffffffff8adf5d80
RBP: 0000000000000001 R08: dffffc0000000000 R09: 1ffffffff2162048
R10: dffffc0000000000 R11: fffffbfff2162049 R12: dffffc0000000000
R13: dffffc0000000000 R14: 00000000000001d8 R15: 00000000000001e8
FS:  0000555592168500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c43885c CR3: 000000004971e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	c0 b9 a0 8b be 19 03 	sarb   $0x3,0x19be8ba0(%rcx)
   7:	00 00                	add    %al,(%rax)
   9:	48 c7 c2 00 ba a0 8b 	mov    $0xffffffff8ba0ba00,%rdx
  10:	e8 3a 00 0a f8       	call   0xf80a004f
  15:	49 bc 00 00 00 00 00 	movabs $0xdffffc0000000000,%r12
  1c:	fc ff df
  1f:	4d 8d 7e 10          	lea    0x10(%r14),%r15
  23:	4c 89 f8             	mov    %r15,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 20 00       	cmpb   $0x0,(%rax,%r12,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	4c 89 ff             	mov    %r15,%rdi
  34:	e8 36 b1 78 f8       	call   0xf878b16f
  39:	4d 8b 3f             	mov    (%r15),%r15
  3c:	4d 85 ff             	test   %r15,%r15
  3f:	74                   	.byte 0x74