syzbot


general protection fault in qfq_deactivate_class

Status: auto-obsoleted due to no activity on 2025/10/19 23:28
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+268bdb68817bd29484c2@syzkaller.appspotmail.com
First crash: 149d, last: 148d
Fix bisection: failed (error log, bisect log)
  
Bug presence (2)
Date Name Commit Repro Result
2025/07/11 linux-5.15.y (ToT) 2f693b607545 C [report] BUG: unable to handle kernel paging request in qfq_deactivate_class
2025/07/11 upstream (ToT) bc9ff192a6c9 C Didn't crash
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.14 general protection fault in qfq_deactivate_class 2 1 1963d 1963d 0/1 auto-closed as invalid on 2020/11/18 22:39
Last patch testing requests (1)
Created Duration User Patch Repo Result
2025/10/19 23:08 18m retest repro linux-5.15.y OK log
Fix bisection attempts (2)
Created Duration User Patch Repo Result
2025/09/03 00:20 1m fix candidate upstream error job log
2025/08/10 13:58 12m bisect fix linux-5.15.y error job log

Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc000000000d: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000068-0x000000000000006f]
CPU: 0 PID: 7523 Comm: syz.0.965 Not tainted 5.15.187-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:qfq_deactivate_class+0x2e/0x1290 net/sched/sch_qfq.c:354
Code: 56 41 55 41 54 53 48 83 ec 60 49 89 f6 49 89 fd 48 bd 00 00 00 00 00 fc ff df e8 1d 51 73 f9 49 8d 7e 68 48 89 f8 48 c1 e8 03 <80> 3c 28 00 74 05 e8 07 ca b8 f9 49 8b 5e 68 4d 8d 7e 58 4c 89 ff
RSP: 0018:ffffc900030eeed8 EFLAGS: 00010202
RAX: 000000000000000d RBX: 0000000000000000 RCX: 0000000000080000
RDX: ffffc90015402000 RSI: 00000000000002cb RDI: 0000000000000068
RBP: dffffc0000000000 R08: ffff88802b519dc0 R09: 0000000000000002
R10: 00000000ffffffff R11: 0000000000000002 R12: ffff888061dc0000
R13: ffff888061dc02c0 R14: 0000000000000000 R15: ffffffff8b02b120
FS:  00007fb9d70aa6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb9d92df394 CR3: 0000000061d16000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 qdisc_tree_reduce_backlog+0x25f/0x430 net/sched/sch_api.c:799
 codel_change+0x8d1/0xc00 net/sched/sch_codel.c:183
 codel_init+0x190/0x330 net/sched/sch_codel.c:202
 qdisc_create+0x7bd/0x1170 net/sched/sch_api.c:1260
 tc_modify_qdisc+0xaad/0x16c0 net/sched/sch_api.c:-1
 rtnetlink_rcv_msg+0x9b9/0xe60 net/core/rtnetlink.c:5650
 netlink_rcv_skb+0x1e0/0x430 net/netlink/af_netlink.c:2489
 netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline]
 netlink_unicast+0x77c/0x920 net/netlink/af_netlink.c:1337
 netlink_sendmsg+0x8ab/0xbc0 net/netlink/af_netlink.c:1905
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 ____sys_sendmsg+0x5a2/0x8c0 net/socket.c:2436
 ___sys_sendmsg+0x1f0/0x260 net/socket.c:2490
 __sys_sendmsg net/socket.c:2519 [inline]
 __do_sys_sendmsg net/socket.c:2528 [inline]
 __se_sys_sendmsg+0x190/0x250 net/socket.c:2526
 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: 0033:0x7fb9d9242929
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:00007fb9d70aa038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fb9d9469fa0 RCX: 00007fb9d9242929
RDX: 000000000000c010 RSI: 0000200000000280 RDI: 0000000000000003
RBP: 00007fb9d92c4b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fb9d9469fa0 R15: 00007fff8a4bdcf8
 </TASK>
Modules linked in:
---[ end trace d6b6b27b31db5c5f ]---
RIP: 0010:qfq_deactivate_class+0x2e/0x1290 net/sched/sch_qfq.c:354
Code: 56 41 55 41 54 53 48 83 ec 60 49 89 f6 49 89 fd 48 bd 00 00 00 00 00 fc ff df e8 1d 51 73 f9 49 8d 7e 68 48 89 f8 48 c1 e8 03 <80> 3c 28 00 74 05 e8 07 ca b8 f9 49 8b 5e 68 4d 8d 7e 58 4c 89 ff
RSP: 0018:ffffc900030eeed8 EFLAGS: 00010202
RAX: 000000000000000d RBX: 0000000000000000 RCX: 0000000000080000
RDX: ffffc90015402000 RSI: 00000000000002cb RDI: 0000000000000068
RBP: dffffc0000000000 R08: ffff88802b519dc0 R09: 0000000000000002
R10: 00000000ffffffff R11: 0000000000000002 R12: ffff888061dc0000
R13: ffff888061dc02c0 R14: 0000000000000000 R15: ffffffff8b02b120
FS:  00007fb9d70aa6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb9d92df394 CR3: 0000000061d16000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	56                   	push   %rsi
   1:	41 55                	push   %r13
   3:	41 54                	push   %r12
   5:	53                   	push   %rbx
   6:	48 83 ec 60          	sub    $0x60,%rsp
   a:	49 89 f6             	mov    %rsi,%r14
   d:	49 89 fd             	mov    %rdi,%r13
  10:	48 bd 00 00 00 00 00 	movabs $0xdffffc0000000000,%rbp
  17:	fc ff df
  1a:	e8 1d 51 73 f9       	call   0xf973513c
  1f:	49 8d 7e 68          	lea    0x68(%r14),%rdi
  23:	48 89 f8             	mov    %rdi,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	80 3c 28 00          	cmpb   $0x0,(%rax,%rbp,1) <-- trapping instruction
  2e:	74 05                	je     0x35
  30:	e8 07 ca b8 f9       	call   0xf9b8ca3c
  35:	49 8b 5e 68          	mov    0x68(%r14),%rbx
  39:	4d 8d 7e 58          	lea    0x58(%r14),%r15
  3d:	4c 89 ff             	mov    %r15,%rdi

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/10 18:58 linux-5.15.y 2f693b607545 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan general protection fault in qfq_deactivate_class
2025/07/11 01:45 linux-5.15.y 2f693b607545 3cda49cf .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 BUG: unable to handle kernel paging request in qfq_deactivate_class
2025/07/10 22:19 linux-5.15.y 2f693b607545 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 BUG: unable to handle kernel paging request in qfq_deactivate_class
2025/07/10 21:48 linux-5.15.y 2f693b607545 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 BUG: unable to handle kernel paging request in qfq_deactivate_class
2025/07/10 19:20 linux-5.15.y 2f693b607545 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 BUG: unable to handle kernel paging request in qfq_deactivate_class
2025/07/10 19:19 linux-5.15.y 2f693b607545 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 BUG: unable to handle kernel paging request in qfq_deactivate_class
* Struck through repros no longer work on HEAD.