general protection fault in __btf_resolve_helper_id

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    9e50b94b Add linux-next specific files for 20200703
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=10327e6d100000
kernel config:  https://syzkaller.appspot.com/x/.config?x=f99cc0faa1476ed6
dashboard link: https://syzkaller.appspot.com/bug?extid=ee09bda7017345f1fbe6
compiler:       gcc (GCC) 10.1.0-syz 20200507
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15d9e39b100000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15b597d3100000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+ee09bda7017345f1fbe6@xxxxxxxxxxxxxxxxxxxxxxxxx

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: 6799 Comm: syz-executor682 Not tainted 5.8.0-rc3-next-20200703-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__btf_resolve_helper_id+0x149/0xb10 kernel/bpf/btf.c:4102
Code: 80 3c 03 00 0f 85 dd 08 00 00 48 8b 05 70 46 0a 0b 48 8d 78 48 48 89 04 24 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 03 0f 8e 50 09 00 00 48 8b 04 24 31 ff
RSP: 0018:ffffc90001637378 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 1ffffffff1926068 RCX: ffffffff816aa4b6
RDX: 0000000000000009 RSI: ffffffff8188bcb1 RDI: 0000000000000048
RBP: ffffffff818ba3d0 R08: ffffc900016373e4 R09: ffffc90001637670
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffff888096648260 R15: ffff888096648000
FS:  0000000000cc2880(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000282 CR3: 00000000a6dbe000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 btf_resolve_helper_id+0x10c/0x1c0 kernel/bpf/btf.c:4164
 check_helper_call+0x1641/0x5650 kernel/bpf/verifier.c:4721
 do_check kernel/bpf/verifier.c:8938 [inline]
 do_check_common+0x7253/0xc2d0 kernel/bpf/verifier.c:10574
 do_check_main kernel/bpf/verifier.c:10640 [inline]
 bpf_check+0x857f/0xce51 kernel/bpf/verifier.c:11093
 bpf_prog_load+0xdaf/0x1b50 kernel/bpf/syscall.c:2194
 __do_sys_bpf+0x1edf/0x4b10 kernel/bpf/syscall.c:4112
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:367
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x440379
Code: Bad RIP value.
RSP: 002b:00007ffee37aa6d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440379
RDX: 0000000000000048 RSI: 0000000020000080 RDI: 0000000000000005
RBP: 00000000006ca018 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 0000000000401c00
R13: 0000000000401c90 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace d5a7c4fec6f343c9 ]---
RIP: 0010:__btf_resolve_helper_id+0x149/0xb10 kernel/bpf/btf.c:4102
Code: 80 3c 03 00 0f 85 dd 08 00 00 48 8b 05 70 46 0a 0b 48 8d 78 48 48 89 04 24 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 03 0f 8e 50 09 00 00 48 8b 04 24 31 ff
RSP: 0018:ffffc90001637378 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 1ffffffff1926068 RCX: ffffffff816aa4b6
RDX: 0000000000000009 RSI: ffffffff8188bcb1 RDI: 0000000000000048
RBP: ffffffff818ba3d0 R08: ffffc900016373e4 R09: ffffc90001637670
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffff888096648260 R15: ffff888096648000
FS:  0000000000cc2880(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000282 CR3: 00000000a6dbe000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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