syzbot


BUG: unable to handle kernel paging request in tcf_idrinfo_destroy

Status: upstream: reported on 2025/12/13 15:35
Subsystems: net
[Documentation on labels]
Reported-by: syzbot+8f1c492ffa4644ff3826@syzkaller.appspotmail.com
Fix commit: net/sched: act_api: avoid dereferencing ERR_PTR in tcf_idrinfo_destroy
Patched on: [ci-qemu-gce-upstream-auto ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm32 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-upstream-gce-leak ci-upstream-kasan-badwrites-root ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-kmsan-gce-386-root ci-upstream-kmsan-gce-root ci-upstream-linux-next-kasan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci-upstream-rust-kasan-gce ci2-upstream-fs ci2-upstream-kcsan-gce], missing on: [ci-qemu-native-arm64-kvm ci-qemu2-riscv64 ci-snapshot-upstream-root ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-arm64 ci2-upstream-usb]
First crash: 35d, last: 35d
Discussions (2)
Title Replies (including bot) Last reply
[PATCH] net/sched: act_api: avoid dereferencing ERR_PTR in tcf_idrinfo_destroy 4 (4) 2026/01/07 01:40
[syzbot] [net?] BUG: unable to handle kernel paging request in tcf_idrinfo_destroy 0 (1) 2025/12/13 15:35
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
android-6-1 KASAN: null-ptr-deref Read in tcf_idrinfo_destroy 11 5 1d01h 17d 0/2 premoderation: reported on 2025/12/27 14:00
android-54 KASAN: null-ptr-deref Read in tcf_idrinfo_destroy 11 C 11829 232d 979d 0/2 upstream: reported C repro on 2023/05/10 22:23
upstream KASAN: null-ptr-deref Read in tcf_idrinfo_destroy net 11 C 115 1743d 1934d 20/29 fixed on 2021/04/09 19:46

Sample crash report:
Unable to handle kernel paging request at virtual address dfff80000000001c
KASAN: null-ptr-deref in range [0x00000000000000e0-0x00000000000000e7]
Mem abort info:
  ESR = 0x0000000096000005
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x05: level 1 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000
  CM = 0, WnR = 0, TnD = 0, TagAccess = 0
  GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[dfff80000000001c] address between user and kernel address ranges
Internal error: Oops: 0000000096000005 [#1]  SMP
Modules linked in:
CPU: 1 UID: 0 PID: 252 Comm: kworker/u8:4 Not tainted syzkaller #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/03/2025
Workqueue: netns cleanup_net
pstate: 63400005 (nZCv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : tc_act_in_hw include/net/pkt_cls.h:288 [inline]
pc : tcf_idrinfo_destroy+0xac/0x280 net/sched/act_api.c:943
lr : tcf_idrinfo_destroy+0x9c/0x280 net/sched/act_api.c:942
sp : ffff80009bc477e0
x29: ffff80009bc47850 x28: 0000000000000001 x27: 1ffff0001251a7a6
x26: 0000000000000000 x25: ffff80009bc477e0 x24: 1ffff00013788efc
x23: dfff800000000000 x22: 00000000000000e0 x21: fffffffffffffff0
x20: ffff8000928d3d30 x19: ffff0000d7040000 x18: 00000000ffffffff
x17: ffff8000894c2344 x16: ffff80008ad6b188 x15: 0000000000000002
x14: 1ffff00013788ee6 x13: 0000000000000000 x12: 0000000000000000
x11: ffff700013788ee8 x10: 0000000000000000 x9 : 2310c4dc04add800
x8 : 000000000000001c x7 : 0000000000000000 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000010
x2 : 0000000000000000 x1 : 0000000000000000 x0 : fffffffffffffff0
Call trace:
 tc_act_in_hw include/net/pkt_cls.h:288 [inline] (P)
 tcf_idrinfo_destroy+0xac/0x280 net/sched/act_api.c:943 (P)
 tc_action_net_exit include/net/act_api.h:183 [inline]
 gact_exit_net+0x9c/0x104 net/sched/act_gact.c:310
 ops_exit_list net/core/net_namespace.c:205 [inline]
 ops_undo_list+0x428/0x7ec net/core/net_namespace.c:252
 cleanup_net+0x3f8/0x6dc net/core/net_namespace.c:695
 process_one_work+0x7e8/0x155c kernel/workqueue.c:3263
 process_scheduled_works kernel/workqueue.c:3346 [inline]
 worker_thread+0x958/0xed8 kernel/workqueue.c:3427
 kthread+0x5fc/0x75c kernel/kthread.c:463
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844
Code: b4000b40 9103c016 aa0003f5 d343fec8 (38f76908) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	b4000b40 	cbz	x0, 0x168
   4:	9103c016 	add	x22, x0, #0xf0
   8:	aa0003f5 	mov	x21, x0
   c:	d343fec8 	lsr	x8, x22, #3
* 10:	38f76908 	ldrsb	w8, [x8, x23] <-- trapping instruction

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/09 15:28 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 05c93f3395ed d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: unable to handle kernel paging request in tcf_idrinfo_destroy
* Struck through repros no longer work on HEAD.