syzbot


general protection fault in print_reg_state

Status: upstream: reported C repro on 2025/09/23 09:02
Subsystems: bpf
[Documentation on labels]
Reported-by: syzbot+d36d5ae81e1b0a53ef58@syzkaller.appspotmail.com
First crash: 20h57m, last: 20h17m
Discussions (4)
Title Replies (including bot) Last reply
[PATCH 1/1] bpf: fix NULL pointer dereference in print_reg_state() 2 (2) 2025/09/23 18:52
[PATCH v2] bpf: fix NULL pointer dereference in print_reg_state() 1 (1) 2025/09/23 17:47
[syzbot] [bpf?] general protection fault in print_reg_state 0 (2) 2025/09/23 17:10
[PATCH 1/1] bpf: fix NULL pointer dereference in print_reg_state() 1 (1) 2025/09/23 16:41
Last patch testing requests (1)
Created Duration User Patch Repo Result
2025/09/23 17:10 19m listout@listout.xyz patch upstream OK log

Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xdffffc000000000c: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000060-0x0000000000000067]
CPU: 1 UID: 0 PID: 6117 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:print_reg_state+0x2dc/0x1010 kernel/bpf/log.c:719
Code: c1 ea 03 80 3c 02 00 0f 85 5c 0c 00 00 48 ba 00 00 00 00 00 fc ff df 4c 8b 7b 08 49 8d 47 60 48 89 c1 48 89 04 24 48 c1 e9 03 <0f> b6 14 11 84 d2 74 06 0f 8e 45 0b 00 00 41 0f b6 57 60 48 8b 44
RSP: 0018:ffffc90004e67398 EFLAGS: 00010206
RAX: 0000000000000060 RBX: ffff8880275a5000 RCX: 000000000000000c
RDX: dffffc0000000000 RSI: ffffffff81daeb8b RDI: 0000000000000005
RBP: ffffc90004e674b0 R08: 0000000000000005 R09: 0000000000000002
R10: 0000000000000000 R11: 0000000000000000 R12: ffff888037df0000
R13: 0000000000000003 R14: 1ffff920009cce79 R15: 0000000000000000
FS:  0000555587b13500(0000) GS:ffff8880d67b2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000100 CR3: 0000000033bb5000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 print_verifier_state+0x234/0x1170 kernel/bpf/log.c:775
 do_check kernel/bpf/verifier.c:20071 [inline]
 do_check_common+0x283e/0xb410 kernel/bpf/verifier.c:23264
 do_check_main kernel/bpf/verifier.c:23347 [inline]
 bpf_check+0x869f/0xc670 kernel/bpf/verifier.c:24707
 bpf_prog_load+0xe41/0x2490 kernel/bpf/syscall.c:2979
 __sys_bpf+0x4a3f/0x4de0 kernel/bpf/syscall.c:6029
 __do_sys_bpf kernel/bpf/syscall.c:6139 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:6137 [inline]
 __x64_sys_bpf+0x78/0xc0 kernel/bpf/syscall.c:6137
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4e0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1041d8eec9
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:00007ffd44cefdd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f1041fe5fa0 RCX: 00007f1041d8eec9
RDX: 0000000000000094 RSI: 0000200000000100 RDI: 0000000000000005
RBP: 00007f1041e11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1041fe5fa0 R14: 00007f1041fe5fa0 R15: 0000000000000003
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:print_reg_state+0x2dc/0x1010 kernel/bpf/log.c:719
Code: c1 ea 03 80 3c 02 00 0f 85 5c 0c 00 00 48 ba 00 00 00 00 00 fc ff df 4c 8b 7b 08 49 8d 47 60 48 89 c1 48 89 04 24 48 c1 e9 03 <0f> b6 14 11 84 d2 74 06 0f 8e 45 0b 00 00 41 0f b6 57 60 48 8b 44
RSP: 0018:ffffc90004e67398 EFLAGS: 00010206
RAX: 0000000000000060 RBX: ffff8880275a5000 RCX: 000000000000000c
RDX: dffffc0000000000 RSI: ffffffff81daeb8b RDI: 0000000000000005
RBP: ffffc90004e674b0 R08: 0000000000000005 R09: 0000000000000002
R10: 0000000000000000 R11: 0000000000000000 R12: ffff888037df0000
R13: 0000000000000003 R14: 1ffff920009cce79 R15: 0000000000000000
FS:  0000555587b13500(0000) GS:ffff8880d67b2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000100 CR3: 0000000033bb5000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess):
   0:	c1 ea 03             	shr    $0x3,%edx
   3:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   7:	0f 85 5c 0c 00 00    	jne    0xc69
   d:	48 ba 00 00 00 00 00 	movabs $0xdffffc0000000000,%rdx
  14:	fc ff df
  17:	4c 8b 7b 08          	mov    0x8(%rbx),%r15
  1b:	49 8d 47 60          	lea    0x60(%r15),%rax
  1f:	48 89 c1             	mov    %rax,%rcx
  22:	48 89 04 24          	mov    %rax,(%rsp)
  26:	48 c1 e9 03          	shr    $0x3,%rcx
* 2a:	0f b6 14 11          	movzbl (%rcx,%rdx,1),%edx <-- trapping instruction
  2e:	84 d2                	test   %dl,%dl
  30:	74 06                	je     0x38
  32:	0f 8e 45 0b 00 00    	jle    0xb7d
  38:	41 0f b6 57 60       	movzbl 0x60(%r15),%edx
  3d:	48                   	rex.W
  3e:	8b                   	.byte 0x8b
  3f:	44                   	rex.R

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/23 01:23 upstream cec1e6e5d1ab 0ac7291c .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream general protection fault in print_reg_state
2025/09/23 01:04 upstream cec1e6e5d1ab 0ac7291c .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream general protection fault in print_reg_state
2025/09/23 00:43 upstream cec1e6e5d1ab 0ac7291c .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream general protection fault in print_reg_state
* Struck through repros no longer work on HEAD.