syzbot


general protection fault in skb_queue_tail (4)

Status: moderation: reported on 2025/08/22 15:06
Subsystems: bluetooth
[Documentation on labels]
Reported-by: syzbot+a230c64ea13b6fde67eb@syzkaller.appspotmail.com
First crash: 4d20h, last: 4d20h
Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream general protection fault in skb_queue_tail (2) wireless 2 2 1489d 1498d 0/29 auto-closed as invalid on 2021/10/23 19:22
upstream general protection fault in skb_queue_tail (3) afs 19 C inconclusive done 9 812d 1045d 23/29 fixed on 2023/09/28 17:51
upstream general protection fault in skb_queue_tail 2 C done 35 2312d 2314d 12/29 fixed on 2019/05/27 12:48
linux-4.19 KASAN: use-after-free Write in skb_queue_tail 24 1 1538d 1538d 0/1 auto-closed as invalid on 2021/10/05 02:17

Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 UID: 0 PID: 12120 Comm: syz.4.1338 Tainted: G     U              6.17.0-rc2-syzkaller #0 PREEMPT(full) 
Tainted: [U]=USER
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:__skb_insert include/linux/skbuff.h:2284 [inline]
RIP: 0010:__skb_queue_before include/linux/skbuff.h:2390 [inline]
RIP: 0010:__skb_queue_tail include/linux/skbuff.h:2423 [inline]
RIP: 0010:skb_queue_tail+0xa2/0x150 net/core/skbuff.c:4034
Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 80 00 00 00 4c 89 e2 4c 89 65 08 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 48 89 6b 08 <80> 3c 02 00 75 4f 48 8d 7b 10 49 89 2c 24 48 b8 00 00 00 00 00 fc
RSP: 0018:ffffc90003a4fbb0 EFLAGS: 00010046
RAX: dffffc0000000000 RBX: ffff888028048270 RCX: ffffffff8197ab1c
RDX: 0000000000000000 RSI: 0000000000000283 RDI: ffff88807a64eb48
RBP: ffff88807a64eb40 R08: 0000000000000001 R09: fffff52000749f64
R10: 0000000000000003 R11: 0000000000000000 R12: 0000000000000000
R13: ffff888028048288 R14: ffff888028047000 R15: ffffc90003a4fc40
FS:  00007f0bc62066c0(0000) GS:ffff8881246c4000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000005995a000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 hci_devcd_init+0x12d/0x1c0 net/bluetooth/coredump.c:464
 force_devcd_write+0x1b9/0x340 drivers/bluetooth/hci_vhci.c:352
 full_proxy_write+0x131/0x1a0 fs/debugfs/file.c:388
 vfs_write+0x2a0/0x11d0 fs/read_write.c:684
 ksys_write+0x12a/0x250 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0bc538ebe9
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:00007f0bc6206038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f0bc55b5fa0 RCX: 00007f0bc538ebe9
RDX: 000000000000000e RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007f0bc5411e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f0bc55b6038 R14: 00007f0bc55b5fa0 R15: 00007ffc936fcaf8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__skb_insert include/linux/skbuff.h:2284 [inline]
RIP: 0010:__skb_queue_before include/linux/skbuff.h:2390 [inline]
RIP: 0010:__skb_queue_tail include/linux/skbuff.h:2423 [inline]
RIP: 0010:skb_queue_tail+0xa2/0x150 net/core/skbuff.c:4034
Code: 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 80 00 00 00 4c 89 e2 4c 89 65 08 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 48 89 6b 08 <80> 3c 02 00 75 4f 48 8d 7b 10 49 89 2c 24 48 b8 00 00 00 00 00 fc
RSP: 0018:ffffc90003a4fbb0 EFLAGS: 00010046
RAX: dffffc0000000000 RBX: ffff888028048270 RCX: ffffffff8197ab1c
RDX: 0000000000000000 RSI: 0000000000000283 RDI: ffff88807a64eb48
RBP: ffff88807a64eb40 R08: 0000000000000001 R09: fffff52000749f64
R10: 0000000000000003 R11: 0000000000000000 R12: 0000000000000000
R13: ffff888028048288 R14: ffff888028047000 R15: ffffc90003a4fc40
FS:  00007f0bc62066c0(0000) GS:ffff8881246c4000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000005995a000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	48 89 fa             	mov    %rdi,%rdx
   3:	48 c1 ea 03          	shr    $0x3,%rdx
   7:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1)
   b:	0f 85 80 00 00 00    	jne    0x91
  11:	4c 89 e2             	mov    %r12,%rdx
  14:	4c 89 65 08          	mov    %r12,0x8(%rbp)
  18:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  1f:	fc ff df
  22:	48 c1 ea 03          	shr    $0x3,%rdx
  26:	48 89 6b 08          	mov    %rbp,0x8(%rbx)
* 2a:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1) <-- trapping instruction
  2e:	75 4f                	jne    0x7f
  30:	48 8d 7b 10          	lea    0x10(%rbx),%rdi
  34:	49 89 2c 24          	mov    %rbp,(%r12)
  38:	48                   	rex.W
  39:	b8 00 00 00 00       	mov    $0x0,%eax
  3e:	00 fc                	add    %bh,%ah

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/18 14:59 upstream c17b750b3ad9 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto general protection fault in skb_queue_tail
* Struck through repros no longer work on HEAD.