syzbot


BUG: unable to handle kernel paging request in l2cap_conn_del

Status: upstream: reported on 2025/09/20 18:34
Subsystems: bluetooth
[Documentation on labels]
Reported-by: syzbot+d1bfe010cdd19081abd8@syzkaller.appspotmail.com
First crash: 4d21h, last: 4d21h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [bluetooth?] BUG: unable to handle kernel paging request in l2cap_conn_del 0 (1) 2025/09/20 18:34
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: use-after-free Read in l2cap_conn_del bluetooth 19 C error 12 1060d 1090d 0/29 auto-obsoleted due to no activity on 2023/04/21 10:14
upstream general protection fault in l2cap_conn_del bluetooth 2 2 268d 283d 0/29 auto-obsoleted due to no activity on 2025/04/06 10:01

Sample crash report:
Unable to handle kerne
Unable to handle kernel paging request at virtual address fbd5200000000020
KASAN: maybe wild-memory-access in range [0xdead000000000100-0xdead000000000107]
Mem abort info:
  ESR = 0x0000000096000004
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x04: level 0 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
  CM = 0, WnR = 0, TnD = 0, TagAccess = 0
  GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[fbd5200000000020] address between user and kernel address ranges
Internal error: Oops: 0000000096000004 [#1]  SMP
Modules linked in:
CPU: 1 UID: 0 PID: 7191 Comm: syz.4.84 Not tainted syzkaller #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025
pstate: 83400005 (Nzcv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : l2cap_conn_del+0x260/0x5f0 net/bluetooth/l2cap_core.c:1783
lr : l2cap_conn_del+0x354/0x5f0 net/bluetooth/l2cap_core.c:1783
sp : ffff80009d6674b0
x29: ffff80009d6674d0 x28: 0000000000000001 x27: ffff80008dcedca0
x26: ffff0000d5e18000 x25: dead000000000100 x24: 000000007ffffffe
x23: 0000000000000001 x22: ffff0000c88c1ac0 x21: dead000000000100
x20: dfff800000000000 x19: ffff0000c88c1800 x18: 00000000ffffffff
x17: ffff800093524000 x16: ffff80008b0156e8 x15: 0000000000000001
x14: 1fffe0001abc3001 x13: 0000000000000000 x12: 0000000000000000
x11: ffff60001abc3002 x10: 0000000000ff0100 x9 : 0000000000000000
x8 : 1bd5a00000000020 x7 : ffff80008312a368 x6 : 0000000000000000
x5 : 0000000000000020 x4 : ffff80009d666fb0 x3 : ffff80008a29deb8
x2 : 0000000000000001 x1 : 0000000000000002 x0 : 0000000000000001
Call trace:
 l2cap_conn_del+0x260/0x5f0 net/bluetooth/l2cap_core.c:1783 (P)
 l2cap_disconn_cfm+0x90/0xe0 net/bluetooth/l2cap_core.c:7325
 hci_disconn_cfm include/net/bluetooth/hci_core.h:2097 [inline]
 hci_conn_hash_flush+0x108/0x218 net/bluetooth/hci_conn.c:2599
 hci_dev_close_sync+0x89c/0x1154 net/bluetooth/hci_sync.c:5294
 hci_dev_do_close net/bluetooth/hci_core.c:501 [inline]
 hci_unregister_dev+0x204/0x4c0 net/bluetooth/hci_core.c:2715
 vhci_release+0x12c/0x17c drivers/bluetooth/hci_vhci.c:690
 __fput+0x340/0x75c fs/file_table.c:468
 ____fput+0x20/0x58 fs/file_table.c:496
 task_work_run+0x1dc/0x260 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x524/0x1a14 kernel/exit.c:961
 do_group_exit+0x194/0x22c kernel/exit.c:1102
 get_signal+0x11dc/0x12f8 kernel/signal.c:3034
 arch_do_signal_or_restart+0x274/0x4434 arch/arm64/kernel/signal.c:1619
 exit_to_user_mode_loop+0x7c/0x168 kernel/entry/common.c:40
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 arm64_exit_to_user_mode arch/arm64/kernel/entry-common.c:103 [inline]
 el0_svc+0x170/0x254 arch/arm64/kernel/entry-common.c:745
 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596
Code: 54000e80 52800037 321f77f8 d343ff28 (38746908) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	54000e80 	b.eq	0x1d0  // b.none
   4:	52800037 	mov	w23, #0x1                   	// #1
   8:	321f77f8 	mov	w24, #0x7ffffffe            	// #2147483646
   c:	d343ff28 	lsr	x8, x25, #3
* 10:	38746908 	ldrb	w8, [x8, x20] <-- trapping instruction

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/16 15:59 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 8736259279a3 e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: unable to handle kernel paging request in l2cap_conn_del
* Struck through repros no longer work on HEAD.