BUG: kernel NULL pointer dereference, address: 0000000000000038
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 8000000112c49067 P4D 8000000112c49067 PUD 112fe2067 PMD 0 
Oops: Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 1 PID: 3311 Comm: syz.0.15 Not tainted 6.10.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
RIP: 0010:bpf_net_ctx_get_ri include/linux/filter.h:782 [inline]
RIP: 0010:__bpf_xdp_redirect_map include/linux/filter.h:1631 [inline]
RIP: 0010:cpu_map_redirect+0x17/0xc0 kernel/bpf/cpumap.c:645
Code: 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 89 d0 65 48 8b 0c 25 80 fe 02 00 48 8b 89 90 16 00 00 <8b> 51 38 f6 c2 02 75 2c c7 41 20 00 00 00 00 48 c7 41 18 00 00 00
RSP: 0018:ffffc900001abc30 EFLAGS: 00010246
RAX: 0000000000000008 RBX: ffffc90000f350b8 RCX: 0000000000000000
RDX: 0000000000000008 RSI: 00000000001abce0 RDI: ffff888112b85e00
RBP: ffffc900001abcf8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff81334e50 R12: ffffc900001abc60
R13: 0000000000000022 R14: 0000000000000140 R15: 0000000000000000
FS:  00007fbc1cc1c6c0(0000) GS:ffff888237d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000038 CR3: 0000000119cca000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ___bpf_prog_run+0x5f6/0x2280 kernel/bpf/core.c:2012
 __bpf_prog_run32+0xbb/0xe0 kernel/bpf/core.c:2253
 bpf_dispatcher_nop_func include/linux/bpf.h:1243 [inline]
 __bpf_prog_run include/linux/filter.h:691 [inline]
 bpf_prog_run_xdp include/net/xdp.h:514 [inline]
 tun_build_skb drivers/net/tun.c:1711 [inline]
 tun_get_user+0x4a8/0x12c0 drivers/net/tun.c:1819
 tun_chr_write_iter+0x5a/0xc0 drivers/net/tun.c:2048
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0x2fc/0x490 fs/read_write.c:590
 ksys_write+0x70/0xe0 fs/read_write.c:643
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x8d/0x1a0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fbc1d19175f
Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 29 8c 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 7c 8c 02 00 48
RSP: 002b:00007fbc1cc1c010 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fbc1d320f60 RCX: 00007fbc1d19175f
RDX: 0000000000000022 RSI: 0000000020000a40 RDI: 00000000000000c8
RBP: 00007fbc1d201aa1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000022 R11: 0000000000000293 R12: 0000000000000000
R13: 000000000000000b R14: 00007fbc1d320f60 R15: 00007fff7cdfae58
 </TASK>
Modules linked in:
CR2: 0000000000000038
---[ end trace 0000000000000000 ]---
RIP: 0010:bpf_net_ctx_get_ri include/linux/filter.h:782 [inline]
RIP: 0010:__bpf_xdp_redirect_map include/linux/filter.h:1631 [inline]
RIP: 0010:cpu_map_redirect+0x17/0xc0 kernel/bpf/cpumap.c:645
Code: 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 89 d0 65 48 8b 0c 25 80 fe 02 00 48 8b 89 90 16 00 00 <8b> 51 38 f6 c2 02 75 2c c7 41 20 00 00 00 00 48 c7 41 18 00 00 00
RSP: 0018:ffffc900001abc30 EFLAGS: 00010246
RAX: 0000000000000008 RBX: ffffc90000f350b8 RCX: 0000000000000000
RDX: 0000000000000008 RSI: 00000000001abce0 RDI: ffff888112b85e00
RBP: ffffc900001abcf8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: ffffffff81334e50 R12: ffffc900001abc60
R13: 0000000000000022 R14: 0000000000000140 R15: 0000000000000000
FS:  00007fbc1cc1c6c0(0000) GS:ffff888237d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000038 CR3: 0000000119cca000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	44 00 00             	add    %r8b,(%rax)
   3:	90                   	nop
   4:	90                   	nop
   5:	90                   	nop
   6:	90                   	nop
   7:	90                   	nop
   8:	90                   	nop
   9:	90                   	nop
   a:	90                   	nop
   b:	90                   	nop
   c:	90                   	nop
   d:	90                   	nop
   e:	90                   	nop
   f:	90                   	nop
  10:	90                   	nop
  11:	90                   	nop
  12:	90                   	nop
  13:	f3 0f 1e fa          	endbr64
  17:	48 89 d0             	mov    %rdx,%rax
  1a:	65 48 8b 0c 25 80 fe 	mov    %gs:0x2fe80,%rcx
  21:	02 00
  23:	48 8b 89 90 16 00 00 	mov    0x1690(%rcx),%rcx
* 2a:	8b 51 38             	mov    0x38(%rcx),%edx <-- trapping instruction
  2d:	f6 c2 02             	test   $0x2,%dl
  30:	75 2c                	jne    0x5e
  32:	c7 41 20 00 00 00 00 	movl   $0x0,0x20(%rcx)
  39:	48                   	rex.W
  3a:	c7                   	.byte 0xc7
  3b:	41 18 00             	sbb    %al,(%r8)