Subject: [syzbot] [bpf?] general protection fault in bpf_prog_offload_verifier_prep

From: syzbot <[email-masked]>
Date: Sun, 03 Sep 2023 12:55:00 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    fa09bc40b21a igb: disable virtualization features on 82580
git tree:       net
console+strace: https://syzkaller.appspot.com/x/log.txt?x=13382fa8680000
kernel config:  https://syzkaller.appspot.com/x/.config?x=634e05b4025da9da
dashboard link: https://syzkaller.appspot.com/bug?extid=291100dcb32190ec02a8
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1529c448680000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15db0248680000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/7ab461d84992/disk-fa09bc40.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3ac6d43ab2db/vmlinux-fa09bc40.xz
kernel image: https://storage.googleapis.com/syzbot-assets/778d096a134e/bzImage-fa09bc40.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 1 PID: 5055 Comm: syz-executor625 Not tainted 6.5.0-syzkaller-04012-gfa09bc40b21a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
RIP: 0010:bpf_prog_offload_verifier_prep+0xaa/0x170 kernel/bpf/offload.c:295
Code: 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 a1 00 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b 65 10 4c 89 e2 48 c1 ea 03 <80> 3c 02 00 0f 85 93 00 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8b
RSP: 0018:ffffc900039ff7f8 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffffc9000156e000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff81a8cf76 RDI: ffff888021b25f10
RBP: ffff888021b25f00 R08: 0000000000000001 R09: fffffbfff195203d
R10: ffffffff8ca901ef R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000005 R14: 0000000000000003 R15: ffffc9000156e060
FS:  0000555556071380(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000100 CR3: 0000000022f6b000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 bpf_check+0x52f3/0xabd0 kernel/bpf/verifier.c:19762
 bpf_prog_load+0x153a/0x2270 kernel/bpf/syscall.c:2708
 __sys_bpf+0xbb6/0x4e90 kernel/bpf/syscall.c:5335
 __do_sys_bpf kernel/bpf/syscall.c:5439 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5437 [inline]
 __x64_sys_bpf+0x78/0xc0 kernel/bpf/syscall.c:5437
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f7c0df78ea9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 d1 19 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffde3592128 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f7c0df78ea9
RDX: 0000000000000090 RSI: 0000000020000940 RDI: 0000000000000005
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000100000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:bpf_prog_offload_verifier_prep+0xaa/0x170 kernel/bpf/offload.c:295
Code: 00 fc ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 a1 00 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b 65 10 4c 89 e2 48 c1 ea 03 <80> 3c 02 00 0f 85 93 00 00 00 48 b8 00 00 00 00 00 fc ff df 4d 8b
RSP: 0018:ffffc900039ff7f8 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffffc9000156e000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff81a8cf76 RDI: ffff888021b25f10
RBP: ffff888021b25f00 R08: 0000000000000001 R09: fffffbfff195203d
R10: ffffffff8ca901ef R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000005 R14: 0000000000000003 R15: ffffc9000156e060
FS:  0000555556071380(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000100 CR3: 0000000022f6b000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 3 bytes skipped:
   0:	df 48 89             	fisttps -0x77(%rax)
   3:	fa                   	cli
   4:	48 c1 ea 03          	shr    $0x3,%rdx
   8:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   c:	0f 85 a1 00 00 00    	jne    0xb3
  12:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  19:	fc ff df
  1c:	4c 8b 65 10          	mov    0x10(%rbp),%r12
  20:	4c 89 e2             	mov    %r12,%rdx
  23:	48 c1 ea 03          	shr    $0x3,%rdx
* 27:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1) <-- trapping instruction
  2b:	0f 85 93 00 00 00    	jne    0xc4
  31:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  38:	fc ff df
  3b:	4d                   	rex.WRB
  3c:	8b                   	.byte 0x8b

---
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