Hello,
syzbot has tested the proposed patch but the reproducer still triggered
crash:
KASAN: use-after-free Read in device_release_driver_internal
==================================================================
BUG: KASAN: use-after-free in __mutex_lock_common
kernel/locking/mutex.c:912 [inline]
BUG: KASAN: use-after-free in __mutex_lock+0xf23/0x1360
kernel/locking/mutex.c:1077
Read of size 8 at addr ffff8881d644bd78 by task kworker/0:4/2855
CPU: 0 PID: 2855 Comm: kworker/0:4 Not tainted 5.3.0-rc5+ #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Workqueue: usb_hub_wq hub_event
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0xca/0x13e lib/dump_stack.c:113
print_address_description+0x6a/0x32c mm/kasan/report.c:351
__kasan_report.cold+0x1a/0x33 mm/kasan/report.c:482
kasan_report+0xe/0x12 mm/kasan/common.c:612
__mutex_lock_common kernel/locking/mutex.c:912 [inline]
__mutex_lock+0xf23/0x1360 kernel/locking/mutex.c:1077
device_release_driver_internal+0x23/0x500 drivers/base/dd.c:1162
bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:556
device_del+0x420/0xb10 drivers/base/core.c:2339
usb_disconnect+0x4c3/0x8d0 drivers/usb/core/hub.c:2225
hub_port_connect drivers/usb/core/hub.c:4949 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
port_event drivers/usb/core/hub.c:5359 [inline]
hub_event+0x1454/0x3640 drivers/usb/core/hub.c:5441
process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
worker_thread+0x96/0xe20 kernel/workqueue.c:2415
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Allocated by task 12:
save_stack+0x1b/0x80 mm/kasan/common.c:69
set_track mm/kasan/common.c:77 [inline]
__kasan_kmalloc mm/kasan/common.c:487 [inline]
__kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:460
kmalloc include/linux/slab.h:552 [inline]
kzalloc include/linux/slab.h:748 [inline]
usb_alloc_dev+0x51/0xf95 drivers/usb/core/usb.c:583
hub_port_connect drivers/usb/core/hub.c:5004 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
port_event drivers/usb/core/hub.c:5359 [inline]
hub_event+0x15c0/0x3640 drivers/usb/core/hub.c:5441
process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
worker_thread+0x96/0xe20 kernel/workqueue.c:2415
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Freed by task 2855:
save_stack+0x1b/0x80 mm/kasan/common.c:69
set_track mm/kasan/common.c:77 [inline]
__kasan_slab_free+0x130/0x180 mm/kasan/common.c:449
slab_free_hook mm/slub.c:1423 [inline]
slab_free_freelist_hook mm/slub.c:1474 [inline]
slab_free mm/slub.c:3016 [inline]
kfree+0xe4/0x2f0 mm/slub.c:3957
device_release+0x71/0x200 drivers/base/core.c:1064
kobject_cleanup lib/kobject.c:693 [inline]
kobject_release lib/kobject.c:722 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x171/0x280 lib/kobject.c:739
put_device+0x1b/0x30 drivers/base/core.c:2264
klist_put+0xce/0x170 lib/klist.c:221
bus_remove_device+0x3a4/0x4a0 drivers/base/bus.c:552
device_del+0x420/0xb10 drivers/base/core.c:2339
usb_disconnect+0x4c3/0x8d0 drivers/usb/core/hub.c:2225
hub_port_connect drivers/usb/core/hub.c:4949 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
port_event drivers/usb/core/hub.c:5359 [inline]
hub_event+0x1454/0x3640 drivers/usb/core/hub.c:5441
process_one_work+0x92b/0x1530 kernel/workqueue.c:2269
worker_thread+0x96/0xe20 kernel/workqueue.c:2415
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
The buggy address belongs to the object at ffff8881d644bb80
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 504 bytes inside of
2048-byte region [ffff8881d644bb80, ffff8881d644c380)
The buggy address belongs to the page:
page:ffffea0007591200 refcount:1 mapcount:0 mapping:ffff8881da00c000
index:0xffff8881d6448000 compound_mapcount: 0
flags: 0x200000000010200(slab|head)
raw: 0200000000010200 ffffea000760ac00 0000000200000002 ffff8881da00c000
raw: ffff8881d6448000 00000000800f000a 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8881d644bc00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881d644bc80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881d644bd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8881d644bd80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881d644be00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
Tested on:
commit: eea39f24 usb-fuzzer: main usb gadget fuzzer driver
git tree: https://github.com/google/kasan.git
console output: https://syzkaller.appspot.com/x/log.txt?x=1018661e600000
kernel config: https://syzkaller.appspot.com/x/.config?x=d0c62209eedfd54e
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
patch: https://syzkaller.appspot.com/x/patch.diff?x=1425bc2e600000
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