[v6.1] KASAN: use-after-free Read in event_handler

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: dc5c83b7f5f8 Linux 6.1.178
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=113de449580000
kernel config: https://syzkaller.appspot.com/x/.config?x=872c04466179833f
dashboard link: https://syzkaller.appspot.com/bug?extid=c1ec904fad7e65d908b2
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/96393e4697a3/disk-dc5c83b7.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/0d4afce44fab/vmlinux-dc5c83b7.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4787e310d875/Image-dc5c83b7.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c1ec90...@syzkaller.appspotmail.com

vhci_hcd: release socket
vhci_hcd: disconnect device
==================================================================
BUG: KASAN: use-after-free in __lock_acquire+0x104/0x6634 kernel/locking/lockdep.c:4933
Read of size 8 at addr ffff0000d1995250 by task kworker/u4:5/4384

CPU: 0 PID: 4384 Comm: kworker/u4:5 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026
Workqueue: usbip_event event_handler
Call trace:
dump_backtrace+0x1c4/0x1f0 arch/arm64/kernel/stacktrace.c:158
show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:165
__dump_stack+0x30/0x40 lib/dump_stack.c:88
dump_stack_lvl+0xf4/0x15c lib/dump_stack.c:106
print_address_description+0x88/0x218 mm/kasan/report.c:316
print_report+0x50/0x68 mm/kasan/report.c:420
kasan_report+0xa8/0xfc mm/kasan/report.c:524
__asan_report_load8_noabort+0x2c/0x38 mm/kasan/report_generic.c:351
__lock_acquire+0x104/0x6634 kernel/locking/lockdep.c:4933
lock_acquire+0x20c/0x638 kernel/locking/lockdep.c:5676
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0x6c/0xb0 kernel/locking/spinlock.c:162
unset_event drivers/usb/usbip/usbip_event.c:35 [inline]
event_handler+0x290/0x454 drivers/usb/usbip/usbip_event.c:80
process_one_work+0x7e4/0x13bc kernel/workqueue.c:2292
worker_thread+0x8cc/0xfe8 kernel/workqueue.c:2439
kthread+0x254/0x2e0 kernel/kthread.c:376
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850

Allocated by task 1:
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4c/0x80 mm/kasan/common.c:53
kasan_save_alloc_info+0x24/0x30 mm/kasan/generic.c:505
____kasan_kmalloc mm/kasan/common.c:375 [inline]
__kasan_kmalloc+0xa0/0xb8 mm/kasan/common.c:384
kasan_kmalloc include/linux/kasan.h:211 [inline]
__do_kmalloc_node mm/slab_common.c:936 [inline]
__kmalloc+0xd8/0x180 mm/slab_common.c:949
kmalloc include/linux/slab.h:568 [inline]
kzalloc include/linux/slab.h:699 [inline]
__usb_create_hcd+0x6c/0x740 drivers/usb/core/hcd.c:2581
usb_create_hcd+0x3c/0x50 drivers/usb/core/hcd.c:2679
vhci_hcd_probe+0x108/0x354 drivers/usb/usbip/vhci_hcd.c:1376
platform_probe+0x148/0x1c8 drivers/base/platform.c:1400
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x3a0/0xac4 drivers/base/dd.c:638
__driver_probe_device+0x1c8/0x368 drivers/base/dd.c:804
driver_probe_device+0x78/0x324 drivers/base/dd.c:834
__device_attach_driver+0x28c/0x4c0 drivers/base/dd.c:962
bus_for_each_drv+0x154/0x1e4 drivers/base/bus.c:429
__device_attach+0x2a4/0x3d8 drivers/base/dd.c:1034
device_initial_probe+0x24/0x34 drivers/base/dd.c:1083
bus_probe_device+0xbc/0x1c4 drivers/base/bus.c:489
device_add+0x93c/0xe4c drivers/base/core.c:3712
platform_device_add+0x3f8/0x6f4 drivers/base/platform.c:717
vhci_hcd_init+0x390/0x4b0 drivers/usb/usbip/vhci_hcd.c:1571
do_one_initcall+0x278/0x9f0 init/main.c:1309
do_initcall_level+0x158/0x214 init/main.c:1382
do_initcalls+0x58/0xac init/main.c:1398
do_basic_setup+0x8c/0xa0 init/main.c:1417
kernel_init_freeable+0x35c/0x4f0 init/main.c:1637
kernel_init+0x24/0x1d8 init/main.c:1525
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850

Freed by task 9856:
kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4c/0x80 mm/kasan/common.c:53
kasan_save_free_info+0x38/0x5c mm/kasan/generic.c:516
____kasan_slab_free+0x148/0x1b0 mm/kasan/common.c:237
__kasan_slab_free+0x18/0x28 mm/kasan/common.c:245
kasan_slab_free include/linux/kasan.h:177 [inline]
slab_free_hook mm/slub.c:1729 [inline]
slab_free_freelist_hook+0x16c/0x1e8 mm/slub.c:1755
slab_free mm/slub.c:3687 [inline]
__kmem_cache_free+0xbc/0x21c mm/slub.c:3700
kfree+0xd0/0x1a8 mm/slab_common.c:988
hcd_release drivers/usb/core/hcd.c:2707 [inline]
kref_put include/linux/kref.h:65 [inline]
usb_put_hcd+0x124/0x16c drivers/usb/core/hcd.c:2721
vhci_hcd_remove+0xd8/0x100 drivers/usb/usbip/vhci_hcd.c:1434
platform_remove+0x98/0xf0 drivers/base/platform.c:1422
device_remove drivers/base/dd.c:547 [inline]
__device_release_driver drivers/base/dd.c:1279 [inline]
device_release_driver_internal+0x3d4/0x6e4 drivers/base/dd.c:1305
device_driver_detach+0x48/0x58 drivers/base/dd.c:1341
unbind_store+0x2a8/0x2b4 drivers/base/bus.c:193
drv_attr_store+0x80/0xa4 drivers/base/bus.c:77
sysfs_kf_write+0x1f8/0x274 fs/sysfs/file.c:140
kernfs_fop_write_iter+0x390/0x4b4 fs/kernfs/file.c:352
call_write_iter include/linux/fs.h:2265 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x3c8/0x7c8 fs/read_write.c:584
ksys_write+0x12c/0x228 fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__arm64_sys_write+0x7c/0x90 fs/read_write.c:646
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

The buggy address belongs to the object at ffff0000d1994000
which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 4688 bytes inside of
8192-byte region [ffff0000d1994000, ffff0000d1996000)

The buggy address belongs to the physical page:
page:000000000ffaf86d refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x111990
head:000000000ffaf86d order:3 compound_mapcount:0 compound_pincount:0
flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000010200 0000000000000000 dead000000000122 ffff0000c0002c00
raw: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff0000d1995100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff0000d1995180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff0000d1995200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff0000d1995280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff0000d1995300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
vhci_hcd: stop threads
vhci_hcd: release socket
vhci_hcd: disconnect device


---
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[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 674f684f7c61 Linux 5.15.212
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=13a531b9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f161cbc9aef65db0
dashboard link: https://syzkaller.appspot.com/bug?extid=3c50f29ba24ea553aab3

compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:

disk image: https://storage.googleapis.com/syzbot-assets/f55be2937b89/disk-674f684f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a19fb0ffc049/vmlinux-674f684f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/365d4529a007/bzImage-674f684f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:

Reported-by: syzbot+3c50f2...@syzkaller.appspotmail.com

vhci_hcd: stop threads
vhci_hcd: release socket
vhci_hcd: disconnect device

==================================================================
BUG: KASAN: use-after-free in __lock_acquire+0x107/0x7b50 kernel/locking/lockdep.c:4882
Read of size 8 at addr ffff888148320698 by task kworker/u4:4/1277

CPU: 1 PID: 1277 Comm: kworker/u4:4 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
Workqueue: usbip_event event_handler
Call Trace:
<TASK>
dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
print_address_description+0x60/0x2d0 mm/kasan/report.c:248
__kasan_report mm/kasan/report.c:434 [inline]
kasan_report+0xdf/0x130 mm/kasan/report.c:451
__lock_acquire+0x107/0x7b50 kernel/locking/lockdep.c:4882
lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
_raw_spin_lock_irqsave+0xb0/0x100 kernel/locking/spinlock.c:162
unset_event drivers/usb/usbip/usbip_event.c:35 [inline]
event_handler+0x2a5/0x460 drivers/usb/usbip/usbip_event.c:80
process_one_work+0x867/0xff0 kernel/workqueue.c:2310
worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
kthread+0x42e/0x520 kernel/kthread.c:334
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
</TASK>

Allocated by task 1:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track mm/kasan/common.c:46 [inline]
set_alloc_info mm/kasan/common.c:434 [inline]
____kasan_kmalloc mm/kasan/common.c:513 [inline]
__kasan_kmalloc+0xaf/0xe0 mm/kasan/common.c:522
kmalloc include/linux/slab.h:612 [inline]
kzalloc include/linux/slab.h:738 [inline]
__usb_create_hcd+0x5f/0x830 drivers/usb/core/hcd.c:2587
vhci_hcd_probe+0x1a5/0x370 drivers/usb/usbip/vhci_hcd.c:1393
platform_probe+0x137/0x1c0 drivers/base/platform.c:1391
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x276/0xc70 drivers/base/dd.c:595
__driver_probe_device+0x1f5/0x390 drivers/base/dd.c:775
driver_probe_device+0x4f/0x420 drivers/base/dd.c:805
__device_attach_driver+0x2b0/0x500 drivers/base/dd.c:927
bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
__device_attach+0x2a7/0x480 drivers/base/dd.c:999
bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489
device_add+0xbcf/0x1050 drivers/base/core.c:3427
platform_device_add+0x4bf/0x830 drivers/base/platform.c:712
vhci_hcd_init+0x3c7/0x500 drivers/usb/usbip/vhci_hcd.c:1571
do_one_initcall+0x272/0x730 init/main.c:1315
do_initcall_level+0x13d/0x1f0 init/main.c:1388
do_initcalls+0x4b/0x90 init/main.c:1404
kernel_init_freeable+0x3d5/0x560 init/main.c:1628
kernel_init+0x19/0x1b0 init/main.c:1519
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Freed by task 4317:
kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:1710 [inline]
slab_free_freelist_hook+0xec/0x170 mm/slub.c:1736
slab_free mm/slub.c:3504 [inline]
kfree+0xef/0x2a0 mm/slub.c:4564
vhci_hcd_remove+0x9a/0x100 drivers/usb/usbip/vhci_hcd.c:1431
platform_remove+0x92/0xe0 drivers/base/platform.c:1413
__device_release_driver drivers/base/dd.c:1247 [inline]
device_release_driver_internal+0x44c/0x710 drivers/base/dd.c:1282
unbind_store+0x2e2/0x300 drivers/base/bus.c:193
kernfs_fop_write_iter+0x3a8/0x500 fs/kernfs/file.c:296
call_write_iter include/linux/fs.h:2173 [inline]
new_sync_write fs/read_write.c:507 [inline]
vfs_write+0x748/0xd70 fs/read_write.c:594
ksys_write+0x153/0x260 fs/read_write.c:647
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0

The buggy address belongs to the object at ffff888148320000

which belongs to the cache kmalloc-8k of size 8192

The buggy address is located 1688 bytes inside of
8192-byte region [ffff888148320000, ffff888148322000)
The buggy address belongs to the page:
page:ffffea000520c800 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x148320
head:ffffea000520c800 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x57ff00000010200(slab|head|node=1|zone=2|lastcpupid=0x7ff)
raw: 057ff00000010200 0000000000000000 dead000000000122 ffff888016c42280

raw: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000
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, ts 14287084608, free_ts 0
prep_new_page mm/page_alloc.c:2426 [inline]
get_page_from_freelist+0x24f6/0x2670 mm/page_alloc.c:4192
__alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501
alloc_page_interleave+0x24/0x1e0 mm/mempolicy.c:2031
alloc_slab_page mm/slub.c:1780 [inline]
allocate_slab mm/slub.c:1917 [inline]
new_slab+0xc0/0x4b0 mm/slub.c:1980
___slab_alloc+0x807/0xdd0 mm/slub.c:3013
__slab_alloc mm/slub.c:3100 [inline]
slab_alloc_node mm/slub.c:3191 [inline]
slab_alloc mm/slub.c:3233 [inline]
__kmalloc+0x11d/0x340 mm/slub.c:4408
kmalloc include/linux/slab.h:612 [inline]
kzalloc include/linux/slab.h:738 [inline]
__usb_create_hcd+0x5f/0x830 drivers/usb/core/hcd.c:2587
vhci_hcd_probe+0x1a5/0x370 drivers/usb/usbip/vhci_hcd.c:1393
platform_probe+0x137/0x1c0 drivers/base/platform.c:1391
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x276/0xc70 drivers/base/dd.c:595
__driver_probe_device+0x1f5/0x390 drivers/base/dd.c:775
driver_probe_device+0x4f/0x420 drivers/base/dd.c:805
__device_attach_driver+0x2b0/0x500 drivers/base/dd.c:927
bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
__device_attach+0x2a7/0x480 drivers/base/dd.c:999
bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489
page_owner free stack trace missing

Memory state around the buggy address:

ffff888148320580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888148320600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888148320680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888148320700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888148320780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: 6e2fd6534337 Linux 5.15.213
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=159bcaea580000

kernel config: https://syzkaller.appspot.com/x/.config?x=f161cbc9aef65db0
dashboard link: https://syzkaller.appspot.com/bug?extid=3c50f29ba24ea553aab3
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=174257b1580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1056703e580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d7b46606b13d/disk-6e2fd653.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/da120fdeb081/vmlinux-6e2fd653.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3c2643457e3f/bzImage-6e2fd653.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+3c50f2...@syzkaller.appspotmail.com

vhci_hcd: stop threads
vhci_hcd: release socket
vhci_hcd: disconnect device
==================================================================
BUG: KASAN: use-after-free in __lock_acquire+0x107/0x7b50 kernel/locking/lockdep.c:4882

Read of size 8 at addr ffff888147da54a8 by task kworker/u4:1/144

CPU: 1 PID: 144 Comm: kworker/u4:1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026

vhci_hcd_probe+0xff/0x370 drivers/usb/usbip/vhci_hcd.c:1376

platform_probe+0x137/0x1c0 drivers/base/platform.c:1391
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x276/0xc70 drivers/base/dd.c:595
__driver_probe_device+0x1f5/0x390 drivers/base/dd.c:775
driver_probe_device+0x4f/0x420 drivers/base/dd.c:805
__device_attach_driver+0x2b0/0x500 drivers/base/dd.c:927
bus_for_each_drv+0x184/0x210 drivers/base/bus.c:429
__device_attach+0x2a7/0x480 drivers/base/dd.c:999
bus_probe_device+0xba/0x1d0 drivers/base/bus.c:489
device_add+0xbcf/0x1050 drivers/base/core.c:3427
platform_device_add+0x4bf/0x830 drivers/base/platform.c:712
vhci_hcd_init+0x3c7/0x500 drivers/usb/usbip/vhci_hcd.c:1571
do_one_initcall+0x272/0x730 init/main.c:1315
do_initcall_level+0x13d/0x1f0 init/main.c:1388
do_initcalls+0x4b/0x90 init/main.c:1404
kernel_init_freeable+0x3d5/0x560 init/main.c:1628
kernel_init+0x19/0x1b0 init/main.c:1519
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Freed by task 4361:

kasan_save_stack mm/kasan/common.c:38 [inline]
kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:1710 [inline]
slab_free_freelist_hook+0xec/0x170 mm/slub.c:1736
slab_free mm/slub.c:3504 [inline]
kfree+0xef/0x2a0 mm/slub.c:4564

vhci_hcd_remove+0xe0/0x100 drivers/usb/usbip/vhci_hcd.c:1434

platform_remove+0x92/0xe0 drivers/base/platform.c:1413
__device_release_driver drivers/base/dd.c:1247 [inline]
device_release_driver_internal+0x44c/0x710 drivers/base/dd.c:1282
unbind_store+0x2e2/0x300 drivers/base/bus.c:193
kernfs_fop_write_iter+0x3a8/0x500 fs/kernfs/file.c:296
call_write_iter include/linux/fs.h:2173 [inline]
new_sync_write fs/read_write.c:507 [inline]
vfs_write+0x748/0xd70 fs/read_write.c:594
ksys_write+0x153/0x260 fs/read_write.c:647
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0

The buggy address belongs to the object at ffff888147da4000

which belongs to the cache kmalloc-8k of size 8192

The buggy address is located 5288 bytes inside of
8192-byte region [ffff888147da4000, ffff888147da6000)

The buggy address belongs to the page:

page:ffffea00051f6800 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x147da0
head:ffffea00051f6800 order:3 compound_mapcount:0 compound_pincount:0

flags: 0x57ff00000010200(slab|head|node=1|zone=2|lastcpupid=0x7ff)
raw: 057ff00000010200 0000000000000000 dead000000000122 ffff888016c42280
raw: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000
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, ts 9809550787, free_ts 0

prep_new_page mm/page_alloc.c:2426 [inline]
get_page_from_freelist+0x24f6/0x2670 mm/page_alloc.c:4192
__alloc_pages+0x1ee/0x480 mm/page_alloc.c:5501
alloc_page_interleave+0x24/0x1e0 mm/mempolicy.c:2031
alloc_slab_page mm/slub.c:1780 [inline]
allocate_slab mm/slub.c:1917 [inline]
new_slab+0xc0/0x4b0 mm/slub.c:1980
___slab_alloc+0x807/0xdd0 mm/slub.c:3013
__slab_alloc mm/slub.c:3100 [inline]
slab_alloc_node mm/slub.c:3191 [inline]
slab_alloc mm/slub.c:3233 [inline]

kmem_cache_alloc_trace+0xf9/0x290 mm/slub.c:3250
kmalloc include/linux/slab.h:607 [inline]
kzalloc include/linux/slab.h:738 [inline]
rd_alloc_device+0x6a/0xb0 drivers/target/target_core_rd.c:275
target_alloc_device+0x9e/0x1390 drivers/target/target_core_device.c:721
core_dev_setup_virtual_lun0+0xdd/0x210 drivers/target/target_core_device.c:1044
target_core_init_configfs+0x3b8/0x540 drivers/target/target_core_configfs.c:3638

do_one_initcall+0x272/0x730 init/main.c:1315
do_initcall_level+0x13d/0x1f0 init/main.c:1388
do_initcalls+0x4b/0x90 init/main.c:1404
kernel_init_freeable+0x3d5/0x560 init/main.c:1628
kernel_init+0x19/0x1b0 init/main.c:1519
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

page_owner free stack trace missing

Memory state around the buggy address:

ffff888147da5380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888147da5400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888147da5480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888147da5500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888147da5580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: fb28aa725e05 Linux 6.1.180
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=17c92c9e580000

kernel config: https://syzkaller.appspot.com/x/.config?x=872c04466179833f
dashboard link: https://syzkaller.appspot.com/bug?extid=c1ec904fad7e65d908b2
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
userspace arch: arm64

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15548db9580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12ae74c6580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d420eb944682/disk-fb28aa72.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/affae450ab23/vmlinux-fb28aa72.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b9e6919ed519/Image-fb28aa72.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c1ec90...@syzkaller.appspotmail.com

vhci_hcd: disconnect device
==================================================================
BUG: KASAN: use-after-free in __lock_acquire+0x104/0x6634 kernel/locking/lockdep.c:4933

Read of size 8 at addr ffff0000d1ce48f0 by task kworker/u4:0/9

CPU: 1 PID: 9 Comm: kworker/u4:0 Not tainted syzkaller #0

usb_create_shared_hcd+0x40/0x54 drivers/usb/core/hcd.c:2657
vhci_hcd_probe+0x1a4/0x354 drivers/usb/usbip/vhci_hcd.c:1393

platform_probe+0x148/0x1c8 drivers/base/platform.c:1400
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x3a0/0xac4 drivers/base/dd.c:638
__driver_probe_device+0x1c8/0x368 drivers/base/dd.c:804
driver_probe_device+0x78/0x324 drivers/base/dd.c:834
__device_attach_driver+0x28c/0x4c0 drivers/base/dd.c:962
bus_for_each_drv+0x154/0x1e4 drivers/base/bus.c:429
__device_attach+0x2a4/0x3d8 drivers/base/dd.c:1034
device_initial_probe+0x24/0x34 drivers/base/dd.c:1083
bus_probe_device+0xbc/0x1c4 drivers/base/bus.c:489
device_add+0x93c/0xe4c drivers/base/core.c:3712
platform_device_add+0x3f8/0x6f4 drivers/base/platform.c:717
vhci_hcd_init+0x390/0x4b0 drivers/usb/usbip/vhci_hcd.c:1571
do_one_initcall+0x278/0x9f0 init/main.c:1309
do_initcall_level+0x158/0x214 init/main.c:1382
do_initcalls+0x58/0xac init/main.c:1398
do_basic_setup+0x8c/0xa0 init/main.c:1417
kernel_init_freeable+0x35c/0x4f0 init/main.c:1637
kernel_init+0x24/0x1d8 init/main.c:1525
ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:850

Freed by task 4505:

kasan_save_stack mm/kasan/common.c:46 [inline]
kasan_set_track+0x4c/0x80 mm/kasan/common.c:53
kasan_save_free_info+0x38/0x5c mm/kasan/generic.c:516
____kasan_slab_free+0x148/0x1b0 mm/kasan/common.c:237
__kasan_slab_free+0x18/0x28 mm/kasan/common.c:245
kasan_slab_free include/linux/kasan.h:177 [inline]
slab_free_hook mm/slub.c:1729 [inline]
slab_free_freelist_hook+0x16c/0x1e8 mm/slub.c:1755
slab_free mm/slub.c:3687 [inline]
__kmem_cache_free+0xbc/0x21c mm/slub.c:3700
kfree+0xd0/0x1a8 mm/slab_common.c:988
hcd_release drivers/usb/core/hcd.c:2707 [inline]
kref_put include/linux/kref.h:65 [inline]
usb_put_hcd+0x124/0x16c drivers/usb/core/hcd.c:2721

vhci_hcd_remove+0x98/0x100 drivers/usb/usbip/vhci_hcd.c:1431

platform_remove+0x98/0xf0 drivers/base/platform.c:1422
device_remove drivers/base/dd.c:547 [inline]
__device_release_driver drivers/base/dd.c:1279 [inline]
device_release_driver_internal+0x3d4/0x6e4 drivers/base/dd.c:1305
device_driver_detach+0x48/0x58 drivers/base/dd.c:1341
unbind_store+0x2a8/0x2b4 drivers/base/bus.c:193
drv_attr_store+0x80/0xa4 drivers/base/bus.c:77
sysfs_kf_write+0x1f8/0x274 fs/sysfs/file.c:140
kernfs_fop_write_iter+0x390/0x4b4 fs/kernfs/file.c:352
call_write_iter include/linux/fs.h:2265 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x3c8/0x7c8 fs/read_write.c:584
ksys_write+0x12c/0x228 fs/read_write.c:637
__do_sys_write fs/read_write.c:649 [inline]
__se_sys_write fs/read_write.c:646 [inline]
__arm64_sys_write+0x7c/0x90 fs/read_write.c:646
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x290 arch/arm64/kernel/syscall.c:52
el0_svc_common+0x13c/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x5c/0x134 arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x128 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

The buggy address belongs to the object at ffff0000d1ce4000

which belongs to the cache kmalloc-8k of size 8192

The buggy address is located 2288 bytes inside of
8192-byte region [ffff0000d1ce4000, ffff0000d1ce6000)

The buggy address belongs to the physical page:

page:00000000c8b08ede refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x111ce0
head:00000000c8b08ede order:3 compound_mapcount:0 compound_pincount:0

flags: 0x5ffc00000010200(slab|head|node=0|zone=2|lastcpupid=0x7ff)
raw: 05ffc00000010200 0000000000000000 dead000000000122 ffff0000c0002c00
raw: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:

ffff0000d1ce4780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff0000d1ce4800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff0000d1ce4880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff0000d1ce4900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff0000d1ce4980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb