syzbot


general protection fault in fq_codel_enqueue

Status: upstream: reported on 2025/08/06 04:45
Reported-by: syzbot+97bf6c575e76fd47de20@syzkaller.appspotmail.com
First crash: 22d, last: 22d
Similar bugs (10)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream general protection fault in fq_codel_enqueue (3) net 2 C inconclusive 5 1153d 1399d 22/29 fixed on 2023/02/24 13:50
linux-4.19 general protection fault in fq_codel_enqueue 2 C done 5 1924d 1952d 1/1 fixed on 2020/06/21 14:03
linux-6.1 BUG: unable to handle kernel paging request in fq_codel_enqueue 8 9 2d03h 27d 0/3 upstream: reported on 2025/08/01 20:04
linux-4.19 general protection fault in fq_codel_enqueue (2) 2 C error 14 1094d 1826d 0/1 upstream: reported C repro on 2020/08/28 22:42
android-5-10 general protection fault in fq_codel_enqueue (2) 2 2 494d 495d 0/2 auto-obsoleted due to no activity on 2024/07/20 23:55
android-5-15 general protection fault in fq_codel_enqueue 2 1 524d 524d 0/2 auto-obsoleted due to no activity on 2024/06/21 01:28
linux-4.14 general protection fault in fq_codel_enqueue 2 C inconclusive 6 1356d 1949d 0/1 upstream: reported C repro on 2020/04/27 21:56
upstream general protection fault in fq_codel_enqueue (2) 2 C done 34 1426d 1826d 0/29 closed as invalid on 2021/10/07 21:22
upstream general protection fault in fq_codel_enqueue net 2 C done 25 1873d 1957d 15/29 fixed on 2020/07/17 17:58
android-5-10 general protection fault in fq_codel_enqueue 2 1 1128d 1128d 0/2 auto-obsoleted due to no activity on 2022/10/25 22:19

Sample crash report:
tipc: Resetting bearer <eth:syzkaller0>
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: 4455 Comm: syz.0.36 Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:dequeue_head net/sched/sch_fq_codel.c:120 [inline]
RIP: 0010:fq_codel_drop net/sched/sch_fq_codel.c:168 [inline]
RIP: 0010:fq_codel_enqueue+0xd2d/0x1590 net/sched/sch_fq_codel.c:230
Code: 24 08 48 8b 44 24 20 80 3c 10 00 74 12 4c 89 ef e8 18 37 b8 f9 48 ba 00 00 00 00 00 fc ff df 4d 8b 65 00 4c 89 e0 48 c1 e8 03 <80> 3c 10 00 74 12 4c 89 e7 e8 f5 36 b8 f9 48 ba 00 00 00 00 00 fc
RSP: 0018:ffffc9000310f1c0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 1ffff92000621eac RCX: 1ffff1100c08245a
RDX: dffffc0000000000 RSI: 00000000000079ae RDI: 00000000000079af
RBP: ffffc9000310f310 R08: dffffc0000000000 R09: fffffbfff1ff6e32
R10: fffffbfff1ff6e32 R11: 1ffffffff1ff6e31 R12: 0000000000000000
R13: ffff888060412800 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f033d5ac6c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000001c0 CR3: 000000005b326000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 qdisc_enqueue include/net/sch_generic.h:832 [inline]
 sfb_enqueue+0x9e0/0x17d0 net/sched/sch_sfb.c:405
 dev_qdisc_enqueue+0x48/0x210 net/core/dev.c:3852
 __dev_xmit_skb net/core/dev.c:3936 [inline]
 __dev_queue_xmit+0xd7e/0x2ed0 net/core/dev.c:4253
 tipc_l2_send_msg+0x30a/0x3c0 net/tipc/bearer.c:518
 tipc_bearer_xmit_skb+0x292/0x3c0 net/tipc/bearer.c:577
 tipc_disc_reset+0x52a/0x830 net/tipc/discover.c:419
 tipc_l2_device_event+0x40c/0x5b0 net/tipc/bearer.c:-1
 notifier_call_chain kernel/notifier.c:83 [inline]
 raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:391
 call_netdevice_notifiers_mtu net/core/dev.c:2098 [inline]
 dev_set_mtu_ext+0x432/0x610 net/core/dev.c:8995
 dev_set_mtu+0x41/0xc0 net/core/dev.c:9016
 dev_ifsioc+0x47d/0xe70 net/core/dev_ioctl.c:331
 dev_ioctl+0x55f/0xe50 net/core/dev_ioctl.c:587
 sock_do_ioctl+0x222/0x2f0 net/socket.c:1154
 sock_ioctl+0x4ed/0x6e0 net/socket.c:1257
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f033f786be9
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:00007f033d5ac038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f033f9ae180 RCX: 00007f033f786be9
RDX: 0000200000002280 RSI: 0000000000008922 RDI: 0000000000000005
RBP: 00007f033f809e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f033f9ae218 R14: 00007f033f9ae180 R15: 00007ffd6d554108
 </TASK>
Modules linked in:
---[ end trace f770c5334731169f ]---
RIP: 0010:dequeue_head net/sched/sch_fq_codel.c:120 [inline]
RIP: 0010:fq_codel_drop net/sched/sch_fq_codel.c:168 [inline]
RIP: 0010:fq_codel_enqueue+0xd2d/0x1590 net/sched/sch_fq_codel.c:230
Code: 24 08 48 8b 44 24 20 80 3c 10 00 74 12 4c 89 ef e8 18 37 b8 f9 48 ba 00 00 00 00 00 fc ff df 4d 8b 65 00 4c 89 e0 48 c1 e8 03 <80> 3c 10 00 74 12 4c 89 e7 e8 f5 36 b8 f9 48 ba 00 00 00 00 00 fc
RSP: 0018:ffffc9000310f1c0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 1ffff92000621eac RCX: 1ffff1100c08245a
RDX: dffffc0000000000 RSI: 00000000000079ae RDI: 00000000000079af
RBP: ffffc9000310f310 R08: dffffc0000000000 R09: fffffbfff1ff6e32
R10: fffffbfff1ff6e32 R11: 1ffffffff1ff6e31 R12: 0000000000000000
R13: ffff888060412800 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f033d5ac6c0(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00002000000001c0 CR3: 000000005b326000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	24 08                	and    $0x8,%al
   2:	48 8b 44 24 20       	mov    0x20(%rsp),%rax
   7:	80 3c 10 00          	cmpb   $0x0,(%rax,%rdx,1)
   b:	74 12                	je     0x1f
   d:	4c 89 ef             	mov    %r13,%rdi
  10:	e8 18 37 b8 f9       	call   0xf9b8372d
  15:	48 ba 00 00 00 00 00 	movabs $0xdffffc0000000000,%rdx
  1c:	fc ff df
  1f:	4d 8b 65 00          	mov    0x0(%r13),%r12
  23:	4c 89 e0             	mov    %r12,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	80 3c 10 00          	cmpb   $0x0,(%rax,%rdx,1) <-- trapping instruction
  2e:	74 12                	je     0x42
  30:	4c 89 e7             	mov    %r12,%rdi
  33:	e8 f5 36 b8 f9       	call   0xf9b8372d
  38:	48                   	rex.W
  39:	ba 00 00 00 00       	mov    $0x0,%edx
  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
2025/08/06 04:44 linux-5.15.y c79648372d02 ffe1dd46 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in fq_codel_enqueue
* Struck through repros no longer work on HEAD.