From: syzbot <syzbot+e4b1171e7c5ae2556f9e@syzkaller.appspotmail.com>
To: 3chas3@gmail.com, accessrunner-general@lists.sourceforge.net,
gregkh@linuxfoundation.org,
linux-atm-general@lists.sourceforge.net,
linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com
Subject: [syzbot] [usb?] KASAN: slab-use-after-free Read in lookup_object_or_alloc (4)
Date: Mon, 03 Aug 2026 17:40:25 -0700 [thread overview]
Message-ID: <6a7134f9.13623e66.bdc14.0005.GAE@google.com> (raw)
Hello,
syzbot found the following issue on:
HEAD commit: 11028ab62899 Merge tag 'probes-fixes-v7.2-rc5' of git://gi..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=159225b9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=145fa60d73086782
dashboard link: https://syzkaller.appspot.com/bug?extid=e4b1171e7c5ae2556f9e
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/dbf4cb7b4116/disk-11028ab6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/77761f1559a8/vmlinux-11028ab6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/bb1ed2bbff0e/bzImage-11028ab6.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e4b1171e7c5ae2556f9e@syzkaller.appspotmail.com
ATM dev 0: poll status: error -5
ATM dev 0: polling disabled, set adsl_state to 'start' or 'poll' to resume
==================================================================
BUG: KASAN: slab-use-after-free in timer_is_static_object+0x80/0x90 kernel/time/timer.c:691
Read of size 8 at addr ffff88805443f8f8 by task kworker/0:7/5803
CPU: 0 UID: 0 PID: 5803 Comm: kworker/0:7 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Workqueue: events cxacru_poll_status
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0x13d/0x4b0 mm/kasan/report.c:482
kasan_report+0xdf/0x1c0 mm/kasan/report.c:595
timer_is_static_object+0x80/0x90 kernel/time/timer.c:691
lookup_object_or_alloc.part.0+0x386/0x4f0 lib/debugobjects.c:696
lookup_object_or_alloc lib/debugobjects.c:682 [inline]
debug_object_activate+0x2fd/0x4b0 lib/debugobjects.c:875
debug_timer_activate kernel/time/timer.c:793 [inline]
__mod_timer+0x845/0xca0 kernel/time/timer.c:1124
add_timer_global+0x8e/0xd0 kernel/time/timer.c:1283
__queue_delayed_work+0x331/0x450 kernel/workqueue.c:2585
queue_delayed_work_on+0x180/0x1e0 kernel/workqueue.c:2620
queue_delayed_work include/linux/workqueue.h:714 [inline]
schedule_delayed_work include/linux/workqueue.h:856 [inline]
cxacru_poll_status+0x622/0xdc0 drivers/usb/atm/cxacru.c:931
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Allocated by task 5803:
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
kasan_kmalloc include/linux/kasan.h:263 [inline]
__kmalloc_cache_noprof+0x2e5/0x6c0 mm/slub.c:5489
_kmalloc_noprof include/linux/slab.h:988 [inline]
_kzalloc_noprof include/linux/slab.h:1309 [inline]
cxacru_bind+0xac/0x1440 drivers/usb/atm/cxacru.c:1133
usbatm_usb_probe+0x378/0x1b50 drivers/usb/atm/usbatm.c:1058
cxacru_usb_probe+0x101/0x200 drivers/usb/atm/cxacru.c:1370
usb_probe_interface+0x303/0x8f0 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:628 [inline]
really_probe+0x241/0xa60 drivers/base/dd.c:706
__driver_probe_device+0x20e/0x450 drivers/base/dd.c:868
driver_probe_device+0x4a/0x140 drivers/base/dd.c:898
__device_attach_driver+0x1df/0x320 drivers/base/dd.c:1026
bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
__device_attach+0x1e4/0x4d0 drivers/base/dd.c:1098
device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1153
bus_probe_device+0x64/0x160 drivers/base/bus.c:620
device_add+0x121d/0x1970 drivers/base/core.c:3772
usb_set_configuration+0xd97/0x1c60 drivers/usb/core/message.c:2268
usb_generic_driver_probe+0xa1/0xe0 drivers/usb/core/generic.c:250
usb_probe_device+0xef/0x400 drivers/usb/core/driver.c:291
call_driver_probe drivers/base/dd.c:628 [inline]
really_probe+0x241/0xa60 drivers/base/dd.c:706
__driver_probe_device+0x20e/0x450 drivers/base/dd.c:868
driver_probe_device+0x4a/0x140 drivers/base/dd.c:898
__device_attach_driver+0x1df/0x320 drivers/base/dd.c:1026
bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500
__device_attach+0x1e4/0x4d0 drivers/base/dd.c:1098
device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1153
bus_probe_device+0x64/0x160 drivers/base/bus.c:620
device_add+0x121d/0x1970 drivers/base/core.c:3772
usb_new_device.cold+0x685/0x115c drivers/usb/core/hub.c:2695
hub_port_connect drivers/usb/core/hub.c:5567 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
port_event drivers/usb/core/hub.c:5871 [inline]
hub_event+0x30a3/0x4a60 drivers/usb/core/hub.c:5953
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Freed by task 5718:
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_save_track+0x14/0x30 mm/kasan/common.c:78
kasan_save_free_info+0x3b/0x70 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:253 [inline]
__kasan_slab_free+0x5f/0x80 mm/kasan/common.c:285
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2677 [inline]
slab_free mm/slub.c:6377 [inline]
kfree+0x22b/0x6c0 mm/slub.c:6692
cxacru_unbind+0x1fc/0x3d0 drivers/usb/atm/cxacru.c:1266
usbatm_usb_disconnect+0x449/0x7e0 drivers/usb/atm/usbatm.c:1255
usb_unbind_interface+0x1dd/0x9e0 drivers/usb/core/driver.c:458
device_remove drivers/base/dd.c:618 [inline]
device_remove+0x12a/0x180 drivers/base/dd.c:610
__device_release_driver drivers/base/dd.c:1349 [inline]
device_release_driver_internal+0x44e/0x620 drivers/base/dd.c:1372
bus_remove_device+0x2bc/0x560 drivers/base/bus.c:664
device_del+0x376/0x9b0 drivers/base/core.c:3961
usb_disable_device+0x367/0x810 drivers/usb/core/message.c:1478
usb_disconnect+0x2e2/0x9a0 drivers/usb/core/hub.c:2345
hub_port_connect drivers/usb/core/hub.c:5407 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
port_event drivers/usb/core/hub.c:5871 [inline]
hub_event+0x1c4f/0x4a60 drivers/usb/core/hub.c:5953
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Last potentially related work creation:
kasan_save_stack+0x30/0x50 mm/kasan/common.c:57
kasan_record_aux_stack+0xa7/0xc0 mm/kasan/generic.c:556
insert_work+0x36/0x230 kernel/workqueue.c:2226
__queue_work+0x9bc/0x12b0 kernel/workqueue.c:2401
call_timer_fn+0x19a/0x610 kernel/time/timer.c:1748
expire_timers kernel/time/timer.c:1794 [inline]
__run_timers+0x570/0xb00 kernel/time/timer.c:2374
__run_timer_base kernel/time/timer.c:2386 [inline]
__run_timer_base kernel/time/timer.c:2378 [inline]
run_timer_base+0x114/0x190 kernel/time/timer.c:2395
run_timer_softirq+0x1a/0x50 kernel/time/timer.c:2405
handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
invoke_softirq kernel/softirq.c:496 [inline]
__irq_exit_rcu+0x162/0x210 kernel/softirq.c:735
irq_exit_rcu+0x9/0x30 kernel/softirq.c:752
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
The buggy address belongs to the object at ffff88805443f800
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 248 bytes inside of
freed 1024-byte region [ffff88805443f800, ffff88805443fc00)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x54438
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88813fe23dc0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88813fe23dc0 dead000000000100 dead000000000122
head: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
head: 00fff00000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd2820(GFP_ATOMIC|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1019, tgid 1019 (kworker/u8:7), ts 92204884189, free_ts 91158504294
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1859
prep_new_page mm/page_alloc.c:1867 [inline]
get_page_from_freelist+0xf48/0x3530 mm/page_alloc.c:3946
__alloc_frozen_pages_noprof+0x299/0x2dc0 mm/page_alloc.c:5304
alloc_slab_page mm/slub.c:3266 [inline]
allocate_slab mm/slub.c:3380 [inline]
new_slab+0xa2/0x640 mm/slub.c:3426
refill_objects+0xe3/0x410 mm/slub.c:7310
refill_sheaf mm/slub.c:2804 [inline]
__pcs_replace_empty_main+0x376/0x680 mm/slub.c:4675
alloc_from_pcs mm/slub.c:4773 [inline]
slab_alloc_node mm/slub.c:4905 [inline]
__do_kmalloc_node mm/slub.c:5333 [inline]
__kmalloc_noprof+0x66d/0x820 mm/slub.c:5359
_kmalloc_noprof include/linux/slab.h:992 [inline]
_kzalloc_noprof include/linux/slab.h:1309 [inline]
ieee802_11_parse_elems_full+0x17c/0x3bc0 net/mac80211/parse.c:1073
ieee802_11_parse_elems net/mac80211/ieee80211_i.h:2551 [inline]
ieee80211_rx_mgmt_probe_beacon net/mac80211/ibss.c:1540 [inline]
ieee80211_ibss_rx_queued_mgmt+0xc96/0x1c70 net/mac80211/ibss.c:1571
ieee80211_iface_process_skb net/mac80211/iface.c:1769 [inline]
ieee80211_iface_work+0xa9a/0x1070 net/mac80211/iface.c:1823
cfg80211_wiphy_work+0x2b7/0x550 net/wireless/core.c:538
process_one_work+0xa23/0x1940 kernel/workqueue.c:3322
process_scheduled_works kernel/workqueue.c:3405 [inline]
worker_thread+0x5ef/0xe50 kernel/workqueue.c:3486
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
page last free pid 5873 tgid 5870 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1406 [inline]
__free_frozen_pages+0x79f/0x1090 mm/page_alloc.c:2950
__folio_put+0x3b4/0x5f0 mm/swap.c:112
folio_put include/linux/mm.h:2124 [inline]
put_page include/linux/mm.h:2193 [inline]
put_netmem include/net/netmem.h:394 [inline]
skb_page_unref include/linux/skbuff_ref.h:43 [inline]
__skb_frag_unref include/linux/skbuff_ref.h:56 [inline]
skb_release_data+0x649/0x8e0 net/core/skbuff.c:1110
skb_release_all net/core/skbuff.c:1191 [inline]
__kfree_skb net/core/skbuff.c:1205 [inline]
kfree_skb_napi_cache net/core/skbuff.c:7281 [inline]
skb_attempt_defer_free+0x38d/0x830 net/core/skbuff.c:7319
tcp_eat_recv_skb net/ipv4/tcp.c:1621 [inline]
tcp_recvmsg_locked+0x11ed/0x2a30 net/ipv4/tcp.c:2899
tcp_recvmsg+0x141/0x630 net/ipv4/tcp.c:2944
inet_recvmsg+0xd5/0x4c0 net/ipv4/af_inet.c:894
sock_recvmsg_nosec net/socket.c:1126 [inline]
sock_recvmsg+0x1b8/0x220 net/socket.c:1148
__sys_recvfrom+0x1f2/0x2f0 net/socket.c:2302
__do_sys_recvfrom net/socket.c:2317 [inline]
__se_sys_recvfrom net/socket.c:2313 [inline]
__x64_sys_recvfrom+0xe0/0x1c0 net/socket.c:2313
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Memory state around the buggy address:
ffff88805443f780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88805443f800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88805443f880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88805443f900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88805443f980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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reply other threads:[~2026-08-04 0:40 UTC|newest]
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