syzbot


KASAN: slab-use-after-free Read in event_handler

Status: moderation: reported on 2025/10/03 03:40
Subsystems: usb
[Documentation on labels]
Reported-by: syzbot+f46f05cc6b2d0dcbd698@syzkaller.appspotmail.com
First crash: 4d22h, last: 4d22h

Sample crash report:
vhci_hcd: stop threads
vhci_hcd: release socket
vhci_hcd: disconnect device
vhci_hcd: stop threads
vhci_hcd: release socket
vhci_hcd: disconnect device
vhci_hcd: stop threads
vhci_hcd: release socket
vhci_hcd: disconnect device
vhci_hcd: stop threads
vhci_hcd: release socket
vhci_hcd: disconnect device
vhci_hcd: stop threads
vhci_hcd: release socket
vhci_hcd: disconnect device
vhci_hcd: stop threads
vhci_hcd: release socket
vhci_hcd: disconnect device
vhci_hcd: stop threads
vhci_hcd: release socket
vhci_hcd: disconnect device
vhci_hcd: stop threads
vhci_hcd: release socket
vhci_hcd: disconnect device
==================================================================
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+0xa7/0xf0 kernel/locking/spinlock.c:162
Read of size 1 at addr ffff888146f21d10 by task kworker/u8:3/57

CPU: 0 UID: 0 PID: 57 Comm: kworker/u8:3 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: usbip_event event_handler
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 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:568
 kasan_check_byte include/linux/kasan.h:399 [inline]
 lock_acquire+0x8d/0x360 kernel/locking/lockdep.c:5842
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xa7/0xf0 kernel/locking/spinlock.c:162
 rt_mutex_slowunlock+0xb0/0x8a0 kernel/locking/rtmutex.c:1417
 spin_unlock_irqrestore include/linux/spinlock_rt.h:122 [inline]
 __wake_up_common_lock+0x18a/0x1e0 kernel/sched/wait.c:127
 event_handler+0x3cc/0x480 drivers/usb/usbip/usbip_event.c:96
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 1:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:388 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:405
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4376 [inline]
 __kmalloc_noprof+0x1ef/0x430 mm/slub.c:4388
 kmalloc_noprof include/linux/slab.h:909 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 __usb_create_hcd+0x68/0x930 drivers/usb/core/hcd.c:2570
 vhci_hcd_probe+0x103/0x380 drivers/usb/usbip/vhci_hcd.c:1352
 platform_probe+0xf9/0x190 drivers/base/platform.c:1405
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x26a/0x9e0 drivers/base/dd.c:659
 __driver_probe_device+0x18c/0x2f0 drivers/base/dd.c:801
 driver_probe_device+0x4f/0x430 drivers/base/dd.c:831
 __device_attach_driver+0x2ce/0x530 drivers/base/dd.c:959
 bus_for_each_drv+0x251/0x2e0 drivers/base/bus.c:462
 __device_attach+0x2bb/0x400 drivers/base/dd.c:1031
 bus_probe_device+0x188/0x260 drivers/base/bus.c:537
 device_add+0x7b6/0xb50 drivers/base/core.c:3689
 platform_device_add+0x4b4/0x820 drivers/base/platform.c:716
 platform_device_register_full+0x46c/0x570 drivers/base/platform.c:844
 vhci_hcd_init+0x1bc/0x320 drivers/usb/usbip/vhci_hcd.c:1533
 do_one_initcall+0x233/0x820 init/main.c:1269
 do_initcall_level+0x104/0x190 init/main.c:1331
 do_initcalls+0x59/0xa0 init/main.c:1347
 kernel_init_freeable+0x334/0x4b0 init/main.c:1579
 kernel_init+0x1d/0x1d0 init/main.c:1469
 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 1:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:243 [inline]
 __kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2422 [inline]
 slab_free mm/slub.c:4695 [inline]
 kfree+0x195/0x550 mm/slub.c:4894
 vhci_hcd_probe+0x2a7/0x380 drivers/usb/usbip/vhci_hcd.c:1391
 platform_probe+0xf9/0x190 drivers/base/platform.c:1405
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x26a/0x9e0 drivers/base/dd.c:659
 __driver_probe_device+0x18c/0x2f0 drivers/base/dd.c:801
 driver_probe_device+0x4f/0x430 drivers/base/dd.c:831
 __device_attach_driver+0x2ce/0x530 drivers/base/dd.c:959
 bus_for_each_drv+0x251/0x2e0 drivers/base/bus.c:462
 __device_attach+0x2bb/0x400 drivers/base/dd.c:1031
 bus_probe_device+0x188/0x260 drivers/base/bus.c:537
 device_add+0x7b6/0xb50 drivers/base/core.c:3689
 platform_device_add+0x4b4/0x820 drivers/base/platform.c:716
 platform_device_register_full+0x46c/0x570 drivers/base/platform.c:844
 vhci_hcd_init+0x1bc/0x320 drivers/usb/usbip/vhci_hcd.c:1533
 do_one_initcall+0x233/0x820 init/main.c:1269
 do_initcall_level+0x104/0x190 init/main.c:1331
 do_initcalls+0x59/0xa0 init/main.c:1347
 kernel_init_freeable+0x334/0x4b0 init/main.c:1579
 kernel_init+0x1d/0x1d0 init/main.c:1469
 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Last potentially related work creation:
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:47
 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:548
 insert_work+0x3d/0x330 kernel/workqueue.c:2184
 __queue_work+0xd63/0x1010 kernel/workqueue.c:2339
 queue_work_on+0x181/0x270 kernel/workqueue.c:2390
 usb_rh_urb_dequeue drivers/usb/core/hcd.c:849 [inline]
 unlink1+0x34c/0x3f0 drivers/usb/core/hcd.c:1584
 usb_hcd_unlink_urb+0xd9/0x1a0 drivers/usb/core/hcd.c:1621
 usb_kill_urb+0x10c/0x2d0 drivers/usb/core/urb.c:711
 hub_quiesce+0x210/0x320 drivers/usb/core/hub.c:1416
 hub_suspend+0x7e7/0x990 drivers/usb/core/hub.c:4007
 usb_suspend_interface drivers/usb/core/driver.c:1323 [inline]
 usb_suspend_both+0x28d/0x1060 drivers/usb/core/driver.c:1428
 usb_runtime_suspend+0x58/0x110 drivers/usb/core/driver.c:1963
 __rpm_callback+0x2bb/0x7a0 drivers/base/power/runtime.c:406
 rpm_callback drivers/base/power/runtime.c:460 [inline]
 rpm_suspend+0x84e/0x1710 drivers/base/power/runtime.c:695
 __pm_runtime_suspend+0x12c/0x1a0 drivers/base/power/runtime.c:1162
 pm_runtime_put_sync_autosuspend include/linux/pm_runtime.h:695 [inline]
 usb_new_device+0xba2/0x16e0 drivers/usb/core/hub.c:2726
 register_root_hub+0x275/0x590 drivers/usb/core/hcd.c:994
 usb_add_hcd+0xba1/0x1050 drivers/usb/core/hcd.c:2993
 vhci_hcd_probe+0x144/0x380 drivers/usb/usbip/vhci_hcd.c:1363
 platform_probe+0xf9/0x190 drivers/base/platform.c:1405
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x26a/0x9e0 drivers/base/dd.c:659
 __driver_probe_device+0x18c/0x2f0 drivers/base/dd.c:801
 driver_probe_device+0x4f/0x430 drivers/base/dd.c:831
 __device_attach_driver+0x2ce/0x530 drivers/base/dd.c:959
 bus_for_each_drv+0x251/0x2e0 drivers/base/bus.c:462
 __device_attach+0x2bb/0x400 drivers/base/dd.c:1031
 bus_probe_device+0x188/0x260 drivers/base/bus.c:537
 device_add+0x7b6/0xb50 drivers/base/core.c:3689
 platform_device_add+0x4b4/0x820 drivers/base/platform.c:716
 platform_device_register_full+0x46c/0x570 drivers/base/platform.c:844
 vhci_hcd_init+0x1bc/0x320 drivers/usb/usbip/vhci_hcd.c:1533
 do_one_initcall+0x233/0x820 init/main.c:1269
 do_initcall_level+0x104/0x190 init/main.c:1331
 do_initcalls+0x59/0xa0 init/main.c:1347
 kernel_init_freeable+0x334/0x4b0 init/main.c:1579
 kernel_init+0x1d/0x1d0 init/main.c:1469
 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Second to last potentially related work creation:
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:47
 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:548
 insert_work+0x3d/0x330 kernel/workqueue.c:2184
 __queue_work+0xd63/0x1010 kernel/workqueue.c:2339
 queue_work_on+0x181/0x270 kernel/workqueue.c:2390
 rh_call_control drivers/usb/core/hcd.c:711 [inline]
 rh_urb_enqueue drivers/usb/core/hcd.c:821 [inline]
 usb_hcd_submit_urb+0x1505/0x1a80 drivers/usb/core/hcd.c:1542
 usb_start_wait_urb+0x114/0x4c0 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
 get_port_status drivers/usb/core/hub.c:611 [inline]
 hub_ext_port_status+0x116/0x820 drivers/usb/core/hub.c:628
 usb_hub_port_status drivers/usb/core/hub.c:678 [inline]
 hub_activate+0x77d/0x1a60 drivers/usb/core/hub.c:1189
 process_one_work kernel/workqueue.c:3236 [inline]
 process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff888146f20000
 which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 7440 bytes inside of
 freed 8192-byte region [ffff888146f20000, ffff888146f22000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x146f20
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x500000000000040(head|node=1|zone=2)
page_type: f5(slab)
raw: 0500000000000040 ffff888019842280 dead000000000122 0000000000000000
raw: 0000000000000000 0000000080020002 00000000f5000000 0000000000000000
head: 0500000000000040 ffff888019842280 dead000000000122 0000000000000000
head: 0000000000000000 0000000080020002 00000000f5000000 0000000000000000
head: 0500000000000003 ffffea00051bc801 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 1, tgid 1 (swapper/0), ts 19592829893, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1851
 prep_new_page mm/page_alloc.c:1859 [inline]
 get_page_from_freelist+0x2119/0x21b0 mm/page_alloc.c:3858
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5148
 alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2416
 alloc_slab_page mm/slub.c:2492 [inline]
 allocate_slab+0x8a/0x370 mm/slub.c:2660
 new_slab mm/slub.c:2714 [inline]
 ___slab_alloc+0x8d1/0xdc0 mm/slub.c:3901
 __slab_alloc mm/slub.c:3992 [inline]
 __slab_alloc_node mm/slub.c:4067 [inline]
 slab_alloc_node mm/slub.c:4228 [inline]
 __do_kmalloc_node mm/slub.c:4375 [inline]
 __kmalloc_noprof+0x145/0x430 mm/slub.c:4388
 kmalloc_noprof include/linux/slab.h:909 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 __usb_create_hcd+0x68/0x930 drivers/usb/core/hcd.c:2570
 vhci_hcd_probe+0x103/0x380 drivers/usb/usbip/vhci_hcd.c:1352
 platform_probe+0xf9/0x190 drivers/base/platform.c:1405
 call_driver_probe drivers/base/dd.c:-1 [inline]
 really_probe+0x26a/0x9e0 drivers/base/dd.c:659
 __driver_probe_device+0x18c/0x2f0 drivers/base/dd.c:801
 driver_probe_device+0x4f/0x430 drivers/base/dd.c:831
 __device_attach_driver+0x2ce/0x530 drivers/base/dd.c:959
 bus_for_each_drv+0x251/0x2e0 drivers/base/bus.c:462
 __device_attach+0x2bb/0x400 drivers/base/dd.c:1031
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888146f21c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888146f21c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888146f21d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff888146f21d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888146f21e00: 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
2025/09/29 03:35 upstream 8f9736633f8c 001c9061 .config console log report [disk image] [vmlinux] [kernel image] ci2-upstream-fs KASAN: slab-use-after-free Read in event_handler
* Struck through repros no longer work on HEAD.