syzbot


general protection fault in htb_qlen_notify

Status: upstream: reported on 2025/07/16 10:29
Reported-by: syzbot+c8853fb09659df151520@syzkaller.appspotmail.com
First crash: 3d13h, last: 3d13h
Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 general protection fault in htb_qlen_notify origin:lts-only 8 C 9 8d01h 9d05h 0/3 upstream: reported C repro on 2025/07/10 18:58
android-5-15 general protection fault in htb_qlen_notify 2 12 2h00m 5d10h 0/2 premoderation: reported on 2025/07/14 13:36
upstream general protection fault in htb_qlen_notify net 10 C done 166 6d20h 16d 26/29 upstream: reported C repro on 2025/07/03 08:17
linux-6.1 general protection fault in htb_qlen_notify origin:lts-only 2 C 4 7d10h 9d05h 0/3 upstream: reported C repro on 2025/07/10 18:56

Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc0000000035: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x00000000000001a8-0x00000000000001af]
CPU: 1 PID: 14702 Comm: syz.3.3086 Not tainted 6.6.98-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:htb_deactivate net/sched/sch_htb.c:613 [inline]
RIP: 0010:htb_qlen_notify+0x31/0xb0 net/sched/sch_htb.c:1489
Code: 41 56 41 55 41 54 53 49 89 f6 49 89 ff 49 bc 00 00 00 00 00 fc ff df e8 ad 90 f4 f8 49 8d 9e a8 01 00 00 49 89 dd 49 c1 ed 03 <43> 0f b6 44 25 00 84 c0 75 48 8b 2b 31 ff 89 ee e8 3a 94 f4 f8 85
RSP: 0018:ffffc90011feed90 EFLAGS: 00010206
RAX: ffffffff889115c3 RBX: 00000000000001a8 RCX: 0000000000080000
RDX: ffffc9000d2db000 RSI: 0000000000001a96 RDI: 0000000000001a97
RBP: dffffc0000000000 R08: ffff88802ea68000 R09: 0000000000000002
R10: 00000000ffffffff R11: 0000000000000002 R12: dffffc0000000000
R13: 0000000000000035 R14: 0000000000000000 R15: ffff88805bf2c000
FS:  00007f1462fff6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d31cff8 CR3: 000000002a6e9000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 qdisc_tree_reduce_backlog+0x28b/0x470 net/sched/sch_api.c:810
 codel_change+0x974/0xdb0 net/sched/sch_codel.c:177
 codel_init+0x1fd/0x3e0 net/sched/sch_codel.c:196
 qdisc_create+0x8eb/0x1050 net/sched/sch_api.c:1322
 tc_modify_qdisc+0xb13/0x1be0 net/sched/sch_api.c:-1
 rtnetlink_rcv_msg+0x7c7/0xf10 net/core/rtnetlink.c:6475
 netlink_rcv_skb+0x216/0x480 net/netlink/af_netlink.c:2537
 netlink_unicast_kernel net/netlink/af_netlink.c:1323 [inline]
 netlink_unicast+0x750/0x8c0 net/netlink/af_netlink.c:1349
 netlink_sendmsg+0x8c1/0xbe0 net/netlink/af_netlink.c:1891
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 ____sys_sendmsg+0x5bf/0x950 net/socket.c:2595
 ___sys_sendmsg+0x220/0x290 net/socket.c:2649
 __sys_sendmsg net/socket.c:2678 [inline]
 __do_sys_sendmsg net/socket.c:2687 [inline]
 __se_sys_sendmsg+0x1a5/0x270 net/socket.c:2685
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f146318e929
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:00007f1462fff038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f14633b5fa0 RCX: 00007f146318e929
RDX: 0000000000004000 RSI: 0000200000000140 RDI: 0000000000000003
RBP: 00007f1463210b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f14633b5fa0 R15: 00007ffd9206c138
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:htb_deactivate net/sched/sch_htb.c:613 [inline]
RIP: 0010:htb_qlen_notify+0x31/0xb0 net/sched/sch_htb.c:1489
Code: 41 56 41 55 41 54 53 49 89 f6 49 89 ff 49 bc 00 00 00 00 00 fc ff df e8 ad 90 f4 f8 49 8d 9e a8 01 00 00 49 89 dd 49 c1 ed 03 <43> 0f b6 44 25 00 84 c0 75 48 8b 2b 31 ff 89 ee e8 3a 94 f4 f8 85
RSP: 0018:ffffc90011feed90 EFLAGS: 00010206
RAX: ffffffff889115c3 RBX: 00000000000001a8 RCX: 0000000000080000
RDX: ffffc9000d2db000 RSI: 0000000000001a96 RDI: 0000000000001a97
RBP: dffffc0000000000 R08: ffff88802ea68000 R09: 0000000000000002
R10: 00000000ffffffff R11: 0000000000000002 R12: dffffc0000000000
R13: 0000000000000035 R14: 0000000000000000 R15: ffff88805bf2c000
FS:  00007f1462fff6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d31cff8 CR3: 000000002a6e9000 CR4: 00000000003506e0
----------------
Code disassembly (best guess):
   0:	41 56                	push   %r14
   2:	41 55                	push   %r13
   4:	41 54                	push   %r12
   6:	53                   	push   %rbx
   7:	49 89 f6             	mov    %rsi,%r14
   a:	49 89 ff             	mov    %rdi,%r15
   d:	49 bc 00 00 00 00 00 	movabs $0xdffffc0000000000,%r12
  14:	fc ff df
  17:	e8 ad 90 f4 f8       	call   0xf8f490c9
  1c:	49 8d 9e a8 01 00 00 	lea    0x1a8(%r14),%rbx
  23:	49 89 dd             	mov    %rbx,%r13
  26:	49 c1 ed 03          	shr    $0x3,%r13
* 2a:	43 0f b6 44 25 00    	movzbl 0x0(%r13,%r12,1),%eax <-- trapping instruction
  30:	84 c0                	test   %al,%al
  32:	75 48                	jne    0x7c
  34:	8b 2b                	mov    (%rbx),%ebp
  36:	31 ff                	xor    %edi,%edi
  38:	89 ee                	mov    %ebp,%esi
  3a:	e8 3a 94 f4 f8       	call   0xf8f49479
  3f:	85                   	.byte 0x85

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/16 10:29 linux-6.6.y 9247f4e6573a 124ec9cc .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan general protection fault in htb_qlen_notify
* Struck through repros no longer work on HEAD.