[moderation] [usb?] KASAN: slab-use-after-free Read in ld_usb_release (2)

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Nov 3, 2025, 9:41:29 PM (2 days ago) Nov 3
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Hello,

syzbot found the following issue on:

HEAD commit: e53642b87a4f Merge tag 'v6.18-rc3-smb-server-fixes' of git..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=163f4e14580000
kernel config: https://syzkaller.appspot.com/x/.config?x=e46b8a1c645465a9
dashboard link: https://syzkaller.appspot.com/bug?extid=881ec804fb67c5180473
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
CC: [gre...@linuxfoundation.org linux-...@vger.kernel.org linu...@vger.kernel.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/63c57b92744d/disk-e53642b8.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9ecc5b1f9b62/vmlinux-e53642b8.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f6f2fea77c41/bzImage-e53642b8.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+881ec8...@syzkaller.appspotmail.com

==================================================================
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 ffff8880316e1c20 by task syz.4.2641/15079

CPU: 0 UID: 0 PID: 15079 Comm: syz.4.2641 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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:580
kasan_check_byte include/linux/kasan.h:401 [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
__mutex_unlock_slowpath+0x2f5/0x740 kernel/locking/mutex.c:947
ld_usb_release+0x52f/0x680 drivers/usb/misc/ldusb.c:403
__fput+0x44c/0xa70 fs/file_table.c:468
task_work_run+0x1d4/0x260 kernel/task_work.c:227
get_signal+0x11ec/0x1340 kernel/signal.c:2807
arch_do_signal_or_restart+0xa0/0x790 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop+0x72/0x130 kernel/entry/common.c:40
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa01978efc9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa01a631038 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: fffffffffffffe00 RBX: 00007fa0199e5fa0 RCX: 00007fa01978efc9
RDX: 0000000000000097 RSI: 00002000000002c0 RDI: 0000000000000005
RBP: 00007fa019811f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa0199e6038 R14: 00007fa0199e5fa0 R15: 00007fffcd2910a8
</TASK>

Allocated by task 5972:
kasan_save_stack mm/kasan/common.c:56 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
poison_kmalloc_redzone mm/kasan/common.c:400 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:417
kasan_kmalloc include/linux/kasan.h:262 [inline]
__kmalloc_cache_noprof+0x3d5/0x6f0 mm/slub.c:5763
kmalloc_noprof include/linux/slab.h:957 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
ld_usb_probe+0x78/0xae0 drivers/usb/misc/ldusb.c:659
usb_probe_interface+0x668/0xc30 drivers/usb/core/driver.c:396
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x26d/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+0x2b8/0x400 drivers/base/dd.c:1031
bus_probe_device+0x185/0x260 drivers/base/bus.c:537
device_add+0x7b6/0xb50 drivers/base/core.c:3689
usb_set_configuration+0x1a87/0x20e0 drivers/usb/core/message.c:2210
usb_generic_driver_probe+0x8d/0x150 drivers/usb/core/generic.c:250
usb_probe_device+0x1c4/0x390 drivers/usb/core/driver.c:291
call_driver_probe drivers/base/dd.c:-1 [inline]
really_probe+0x26d/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+0x2b8/0x400 drivers/base/dd.c:1031
bus_probe_device+0x185/0x260 drivers/base/bus.c:537
device_add+0x7b6/0xb50 drivers/base/core.c:3689
usb_new_device+0xa39/0x16f0 drivers/usb/core/hub.c:2694
hub_port_connect drivers/usb/core/hub.c:5566 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5706 [inline]
port_event drivers/usb/core/hub.c:5870 [inline]
hub_event+0x2958/0x4a20 drivers/usb/core/hub.c:5952
process_one_work kernel/workqueue.c:3263 [inline]
process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

Freed by task 43:
kasan_save_stack mm/kasan/common.c:56 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:77
__kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:587
kasan_save_free_info mm/kasan/kasan.h:406 [inline]
poison_slab_object mm/kasan/common.c:252 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284
kasan_slab_free include/linux/kasan.h:234 [inline]
slab_free_hook mm/slub.c:2539 [inline]
slab_free mm/slub.c:6630 [inline]
kfree+0x19a/0x6d0 mm/slub.c:6837
ld_usb_delete drivers/usb/misc/ldusb.c:212 [inline]
ld_usb_disconnect+0x1df/0x2c0 drivers/usb/misc/ldusb.c:774
usb_unbind_interface+0x26e/0x910 drivers/usb/core/driver.c:458
device_remove drivers/base/dd.c:571 [inline]
__device_release_driver drivers/base/dd.c:1274 [inline]
device_release_driver_internal+0x4d9/0x800 drivers/base/dd.c:1297
bus_remove_device+0x34d/0x410 drivers/base/bus.c:579
device_del+0x511/0x8e0 drivers/base/core.c:3878
usb_disable_device+0x3e9/0x8a0 drivers/usb/core/message.c:1418
usb_disconnect+0x330/0x950 drivers/usb/core/hub.c:2344
hub_port_connect drivers/usb/core/hub.c:5406 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5706 [inline]
port_event drivers/usb/core/hub.c:5870 [inline]
hub_event+0x1cf5/0x4a20 drivers/usb/core/hub.c:5952
process_one_work kernel/workqueue.c:3263 [inline]
process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3346
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3427
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

The buggy address belongs to the object at ffff8880316e1c00
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 32 bytes inside of
freed 512-byte region [ffff8880316e1c00, ffff8880316e1e00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x316e0
head: order:2 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 ffff88801a026c80 ffffea0001efc900 dead000000000002
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801a026c80 ffffea0001efc900 dead000000000002
head: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
head: 00fff00000000002 ffffea0000c5b801 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000004
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5198, tgid 5198 (udevadm), ts 33316099171, free_ts 33312014974
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1850
prep_new_page mm/page_alloc.c:1858 [inline]
get_page_from_freelist+0x2365/0x2440 mm/page_alloc.c:3884
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5183
alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416
alloc_slab_page mm/slub.c:3055 [inline]
allocate_slab+0x96/0x350 mm/slub.c:3228
new_slab mm/slub.c:3282 [inline]
___slab_alloc+0xe94/0x18a0 mm/slub.c:4651
__slab_alloc+0x65/0x100 mm/slub.c:4770
__slab_alloc_node mm/slub.c:4846 [inline]
slab_alloc_node mm/slub.c:5268 [inline]
__kmalloc_cache_noprof+0x411/0x6f0 mm/slub.c:5758
kmalloc_noprof include/linux/slab.h:957 [inline]
kzalloc_noprof include/linux/slab.h:1094 [inline]
kernfs_fop_open+0x397/0xca0 fs/kernfs/file.c:641
do_dentry_open+0x953/0x13f0 fs/open.c:965
vfs_open+0x3b/0x340 fs/open.c:1097
do_open fs/namei.c:3975 [inline]
path_openat+0x2ee5/0x3830 fs/namei.c:4134
do_filp_open+0x1fa/0x410 fs/namei.c:4161
do_sys_openat2+0x121/0x1c0 fs/open.c:1437
do_sys_open fs/open.c:1452 [inline]
__do_sys_openat fs/open.c:1468 [inline]
__se_sys_openat fs/open.c:1463 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1463
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
page last free pid 5209 tgid 5209 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1394 [inline]
__free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2906
discard_slab mm/slub.c:3326 [inline]
__put_partials+0x146/0x170 mm/slub.c:3872
put_cpu_partial+0x1f2/0x2e0 mm/slub.c:3947
__slab_free+0x2b9/0x390 mm/slub.c:5921
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:352
kasan_slab_alloc include/linux/kasan.h:252 [inline]
slab_post_alloc_hook mm/slub.c:4970 [inline]
slab_alloc_node mm/slub.c:5280 [inline]
kmem_cache_alloc_noprof+0x367/0x6e0 mm/slub.c:5287
getname_flags+0xb8/0x540 fs/namei.c:146
getname include/linux/fs.h:2922 [inline]
do_sys_openat2+0xbc/0x1c0 fs/open.c:1431
do_sys_open fs/open.c:1452 [inline]
__do_sys_openat fs/open.c:1468 [inline]
__se_sys_openat fs/open.c:1463 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1463
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
ffff8880316e1b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8880316e1b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880316e1c00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880316e1c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880316e1d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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