syzbot


KASAN: global-out-of-bounds Read in __timer_delete

Status: upstream: reported on 2024/04/08 08:31
Subsystems: bluetooth
[Documentation on labels]
Reported-by: syzbot+0a63bf51a80298491d8e@syzkaller.appspotmail.com
First crash: 55d, last: 55d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [bluetooth?] KASAN: global-out-of-bounds Read in __timer_delete 0 (1) 2024/04/08 08:31

Sample crash report:
==================================================================
BUG: KASAN: global-out-of-bounds in timer_is_static_object+0x5f/0x80 kernel/time/timer.c:735
Read of size 8 at addr ffffffff94884578 by task syz-executor.2/7343

CPU: 1 PID: 7343 Comm: syz-executor.2 Not tainted 6.8.0-syzkaller-05271-gf99c5f563c17 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:488
 kasan_report+0x143/0x180 mm/kasan/report.c:601
 timer_is_static_object+0x5f/0x80 kernel/time/timer.c:735
 lookup_object_or_alloc lib/debugobjects.c:581 [inline]
 debug_object_assert_init+0x228/0x440 lib/debugobjects.c:898
 debug_timer_assert_init kernel/time/timer.c:846 [inline]
 debug_assert_init kernel/time/timer.c:891 [inline]
 __timer_delete+0xad/0x380 kernel/time/timer.c:1413
 del_timer include/linux/timer.h:194 [inline]
 try_to_grab_pending+0x159/0xab0 kernel/workqueue.c:2089
 __cancel_work+0xb8/0x390 kernel/workqueue.c:4278
 sco_sock_clear_timer net/bluetooth/sco.c:119 [inline]
 sco_conn_del+0x161/0x310 net/bluetooth/sco.c:200
 hci_disconn_cfm include/net/bluetooth/hci_core.h:2022 [inline]
 hci_conn_hash_flush+0xff/0x240 net/bluetooth/hci_conn.c:2566
 hci_dev_close_sync+0x9ab/0x1050 net/bluetooth/hci_sync.c:5153
 hci_dev_do_close net/bluetooth/hci_core.c:554 [inline]
 hci_unregister_dev+0x1e3/0x4e0 net/bluetooth/hci_core.c:2773
 vhci_release+0x83/0xd0 drivers/bluetooth/hci_vhci.c:674
 __fput+0x429/0x8a0 fs/file_table.c:423
 task_work_run+0x24f/0x310 kernel/task_work.c:180
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0xa1b/0x27e0 kernel/exit.c:878
 do_group_exit+0x207/0x2c0 kernel/exit.c:1027
 get_signal+0x176e/0x1850 kernel/signal.c:2907
 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:105 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:201 [inline]
 syscall_exit_to_user_mode+0xc9/0x360 kernel/entry/common.c:212
 do_syscall_64+0x10a/0x240 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x6d/0x75
RIP: 0033:0x7fb920c7cc9a
Code: Unable to access opcode bytes at 0x7fb920c7cc70.
RSP: 002b:00007fff790ac930 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007fb920c7cc9a
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007fff790ac9ac R08: 00007fff790ac28c R09: 00007fff790ac697
R10: 00007fff790ac310 R11: 0000000000000293 R12: 0000000000000032
R13: 000000000002aad7 R14: 000000000002aac1 R15: 0000000000000003
 </TASK>

The buggy address belongs to the variable:
 xa_init_flags.__key+0x18/0x20

The buggy address belongs to the physical page:
page:ffffea0000522100 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x14884
flags: 0xfff00000004000(reserved|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000004000 ffffea0000522108 ffffea0000522108 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner info is not present (never set?)

Memory state around the buggy address:
 ffffffff94884400: 00 00 00 00 00 00 00 00 00 00 00 00 f9 f9 f9 f9
 ffffffff94884480: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 00 00 00 00
>ffffffff94884500: 00 00 f9 f9 00 00 f9 f9 04 f9 f9 f9 00 00 f9 f9
                                                                ^
 ffffffff94884580: 00 f9 f9 f9 01 f9 f9 f9 00 f9 f9 f9 04 f9 f9 f9
 ffffffff94884600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/04/02 16:59 net f99c5f563c17 6baf5069 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce KASAN: global-out-of-bounds Read in __timer_delete
* Struck through repros no longer work on HEAD.