syzbot


KASAN: slab-use-after-free Read in raw_queue_event (2)

Status: moderation: reported on 2026/01/11 06:38
Subsystems: usb
[Documentation on labels]
Reported-by: syzbot+e033e8eb146e2a10e23f@syzkaller.appspotmail.com
First crash: 9d21h, last: 9d21h
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-use-after-free Read in raw_queue_event usb 19 1 558d 511d 0/29 closed as dup on 2024/09/21 21:01

Sample crash report:
usb 5-1: device descriptor read/64, error -71
usb usb5-port1: attempt power cycle
==================================================================
BUG: KASAN: slab-use-after-free in __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
BUG: KASAN: slab-use-after-free in _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:162
Read of size 1 at addr ffff8880524608b8 by task kworker/1:10/5982

CPU: 1 UID: 0 PID: 5982 Comm: kworker/1:10 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: usb_hub_wq hub_event
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x240 mm/kasan/report.c:482
 kasan_report+0x118/0x150 mm/kasan/report.c:595
 __kasan_check_byte+0x2a/0x40 mm/kasan/common.c:574
 kasan_check_byte include/linux/kasan.h:402 [inline]
 lock_acquire+0x84/0x340 kernel/locking/lockdep.c:5842
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:162
 rtlock_slowlock kernel/locking/rtmutex.c:1894 [inline]
 rtlock_lock kernel/locking/spinlock_rt.c:43 [inline]
 __rt_spin_lock kernel/locking/spinlock_rt.c:49 [inline]
 rt_spin_lock+0x14a/0x3e0 kernel/locking/spinlock_rt.c:57
 spin_lock include/linux/spinlock_rt.h:44 [inline]
 raw_event_queue_add drivers/usb/gadget/legacy/raw_gadget.c:68 [inline]
 raw_queue_event+0x39/0x2e0 drivers/usb/gadget/legacy/raw_gadget.c:240
 gadget_disconnect+0x51/0xf0 drivers/usb/gadget/legacy/raw_gadget.c:388
 set_link_state+0xc0a/0x1220 drivers/usb/gadget/udc/dummy_hcd.c:471
 dummy_hub_control+0xafc/0x1a30 drivers/usb/gadget/udc/dummy_hcd.c:-1
 rh_call_control drivers/usb/core/hcd.c:656 [inline]
 rh_urb_enqueue drivers/usb/core/hcd.c:821 [inline]
 usb_hcd_submit_urb+0xdbe/0x1b60 drivers/usb/core/hcd.c:1542
 usb_start_wait_urb+0x115/0x4f0 drivers/usb/core/message.c:59
 usb_internal_control_msg drivers/usb/core/message.c:103 [inline]
 usb_control_msg+0x232/0x3e0 drivers/usb/core/message.c:154
 usb_clear_port_feature drivers/usb/core/hub.c:456 [inline]
 usb_hub_set_port_power drivers/usb/core/hub.c:894 [inline]
 hub_port_connect drivers/usb/core/hub.c:5607 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5707 [inline]
 port_event drivers/usb/core/hub.c:5871 [inline]
 hub_event+0x2d55/0x4f30 drivers/usb/core/hub.c:5953
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>

Allocated by task 6293:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x1fb/0x6d0 mm/slub.c:5776
 kmalloc_noprof include/linux/slab.h:957 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 dev_new drivers/usb/gadget/legacy/raw_gadget.c:193 [inline]
 raw_open+0x8d/0x530 drivers/usb/gadget/legacy/raw_gadget.c:435
 misc_open+0x2de/0x350 drivers/char/misc.c:163
 chrdev_open+0x4cf/0x5e0 fs/char_dev.c:414
 do_dentry_open+0x7d0/0x1270 fs/open.c:962
 vfs_open+0x3b/0x350 fs/open.c:1094
 do_open fs/namei.c:4628 [inline]
 path_openat+0x342a/0x3df0 fs/namei.c:4787
 do_filp_open+0x1fa/0x410 fs/namei.c:4814
 do_sys_openat2+0x121/0x200 fs/open.c:1430
 do_sys_open fs/open.c:1436 [inline]
 __do_sys_openat fs/open.c:1452 [inline]
 __se_sys_openat fs/open.c:1447 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1447
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 6293:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2540 [inline]
 slab_free mm/slub.c:6670 [inline]
 kfree+0x1bd/0x900 mm/slub.c:6878
 kref_put include/linux/kref.h:65 [inline]
 raw_release+0x191/0x260 drivers/usb/gadget/legacy/raw_gadget.c:474
 __fput+0x45b/0xa80 fs/file_table.c:468
 task_work_run+0x1d4/0x260 kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x694/0x22f0 kernel/exit.c:971
 do_group_exit+0x21c/0x2d0 kernel/exit.c:1112
 get_signal+0x125d/0x1310 kernel/signal.c:3034
 arch_do_signal_or_restart+0x9a/0x7a0 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:41 [inline]
 exit_to_user_mode_loop+0x87/0x4e0 kernel/entry/common.c:75
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x2c1/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888052460000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 2232 bytes inside of
 freed 4096-byte region [ffff888052460000, ffff888052461000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x52460
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x80000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000040 ffff88813ff27140 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000
head: 0080000000000040 ffff88813ff27140 dead000000000122 0000000000000000
head: 0000000000000000 0000000000040004 00000000f5000000 0000000000000000
head: 0080000000000003 ffffea0001491801 00000000ffffffff 00000000ffffffff
head: 0000000000000000 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 6293, tgid 6292 (syz.4.91), ts 187223965101, free_ts 187217645183
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x234/0x290 mm/page_alloc.c:1857
 prep_new_page mm/page_alloc.c:1865 [inline]
 get_page_from_freelist+0x28c0/0x2960 mm/page_alloc.c:3915
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5210
 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2486
 alloc_slab_page mm/slub.c:3075 [inline]
 allocate_slab+0x86/0x3b0 mm/slub.c:3248
 new_slab mm/slub.c:3302 [inline]
 ___slab_alloc+0xb10/0x13e0 mm/slub.c:4656
 __slab_alloc+0xc6/0x1f0 mm/slub.c:4779
 __slab_alloc_node mm/slub.c:4855 [inline]
 slab_alloc_node mm/slub.c:5251 [inline]
 __kmalloc_cache_noprof+0x101/0x6d0 mm/slub.c:5771
 kmalloc_noprof include/linux/slab.h:957 [inline]
 kzalloc_noprof include/linux/slab.h:1094 [inline]
 dev_new drivers/usb/gadget/legacy/raw_gadget.c:193 [inline]
 raw_open+0x8d/0x530 drivers/usb/gadget/legacy/raw_gadget.c:435
 misc_open+0x2de/0x350 drivers/char/misc.c:163
 chrdev_open+0x4cf/0x5e0 fs/char_dev.c:414
 do_dentry_open+0x7d0/0x1270 fs/open.c:962
 vfs_open+0x3b/0x350 fs/open.c:1094
 do_open fs/namei.c:4628 [inline]
 path_openat+0x342a/0x3df0 fs/namei.c:4787
 do_filp_open+0x1fa/0x410 fs/namei.c:4814
 do_sys_openat2+0x121/0x200 fs/open.c:1430
page last free pid 6292 tgid 6292 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1406 [inline]
 __free_frozen_pages+0xfe1/0x1170 mm/page_alloc.c:2943
 discard_slab mm/slub.c:3346 [inline]
 __put_partials+0x149/0x170 mm/slub.c:3886
 __slab_free+0x2af/0x330 mm/slub.c:5952
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x97/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4953 [inline]
 slab_alloc_node mm/slub.c:5263 [inline]
 kmem_cache_alloc_noprof+0x18d/0x6c0 mm/slub.c:5270
 getname_flags+0xb8/0x540 fs/namei.c:146
 user_path_at+0x24/0x60 fs/namei.c:3566
 __do_sys_chdir fs/open.c:558 [inline]
 __se_sys_chdir+0x91/0x280 fs/open.c:552
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888052460780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888052460800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888052460880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                        ^
 ffff888052460900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888052460980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/07 06:34 upstream f0b9d8eb98df d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root KASAN: slab-use-after-free Read in raw_queue_event
* Struck through repros no longer work on HEAD.