syzbot
BUG: unable to handle kernel paging request in qdisc_tree_reduce_backlog
Status:
auto-obsoleted due to no activity on 2025/10/24 23:49
Bug presence:
origin:lts-only
[Documentation on labels]
Reported-by: syzbot+27efb90c117dc054d237@syzkaller.appspotmail.com
First crash: 418d, last: 415d
▶
▼
Bug presence (2)
| Date |
Name |
Commit |
Repro |
Result |
| 2025/07/15 |
linux-5.15.y (ToT) |
89950c454265 |
C
|
[report] BUG: unable to handle kernel paging request in qdisc_tree_reduce_backlog
|
| 2025/07/15 |
upstream (ToT) |
155a3c003e55 |
C
|
Didn't crash |
▶
▼
Last patch testing requests (6)
Sample crash report:
Unable to handle kernel paging request at virtual address dfff800000000004
Mem abort info:
ESR = 0x0000000096000006
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x06: level 2 translation fault
Data abort info:
ISV = 0, ISS = 0x00000006
CM = 0, WnR = 0
[dfff800000000004] address between user and kernel address ranges
Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 4917 Comm: syz.2.283 Not tainted 5.15.188-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : qdisc_tree_reduce_backlog+0x1e8/0x410 net/sched/sch_api.c:794
lr : qdisc_tree_reduce_backlog+0x19c/0x410 net/sched/sch_api.c:786
sp : ffff80001fd96d40
x29: ffff80001fd96d40 x28: 0000000000000004 x27: dfff800000000000
x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000020
x23: 00000000000affe0 x22: ffff8000162edce0 x21: ffff0000d5d95000
x20: 0000000000000000 x19: 0000000000000000 x18: 0000000000000201
x17: 0000000000000002 x16: ffff8000082bf708 x15: 00000000ffffffff
x14: 0000000000ff0100 x13: ffffffffffffffff x12: 0000000000ff0100
x11: 0000000000000201 x10: 0000000000000002 x9 : ffff0000cd3d0000
x8 : 0000000000000000 x7 : ffff80000f8d3b08 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000002
x2 : 0000000000000008 x1 : 0000000000000000 x0 : 0000000000000000
Call trace:
qdisc_tree_reduce_backlog+0x1e8/0x410 net/sched/sch_api.c:794
codel_change+0x70c/0x9f8 net/sched/sch_codel.c:183
codel_init+0x14c/0x2f0 net/sched/sch_codel.c:202
qdisc_create+0x6e4/0xf24 net/sched/sch_api.c:1260
tc_modify_qdisc+0x8bc/0x1308 net/sched/sch_api.c:-1
rtnetlink_rcv_msg+0x9d4/0xd04 net/core/rtnetlink.c:5650
netlink_rcv_skb+0x208/0x3c4 net/netlink/af_netlink.c:2489
rtnetlink_rcv+0x28/0x38 net/core/rtnetlink.c:5668
netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline]
netlink_unicast+0x60c/0x89c net/netlink/af_netlink.c:1337
netlink_sendmsg+0x6e8/0x9cc net/netlink/af_netlink.c:1905
sock_sendmsg_nosec net/socket.c:704 [inline]
__sock_sendmsg net/socket.c:716 [inline]
____sys_sendmsg+0x61c/0x920 net/socket.c:2436
___sys_sendmsg+0x1d0/0x240 net/socket.c:2490
__sys_sendmsg net/socket.c:2519 [inline]
__do_sys_sendmsg net/socket.c:2528 [inline]
__se_sys_sendmsg net/socket.c:2526 [inline]
__arm64_sys_sendmsg+0x1a8/0x254 net/socket.c:2526
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
el0_svc+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
Code: 14000020 f9400339 91008338 d343ff1c (387b6b88)
---[ end trace c2759e0d16939696 ]---
----------------
Code disassembly (best guess):
0: 14000020 b 0x80
4: f9400339 ldr x25, [x25]
8: 91008338 add x24, x25, #0x20
c: d343ff1c lsr x28, x24, #3
* 10: 387b6b88 ldrb w8, [x28, x27] <-- trapping instruction
* Struck through repros no longer work on HEAD.