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 __lock_acquire+0x3a5d/0x5340
kernel/locking/lockdep.c:3665
Read of size 8 at addr ffff8881d4b1e710 by task kworker/1:2/89
CPU: 1 PID: 89 Comm: kworker/1:2 Not tainted 5.2.0-rc6+ #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+0x67/0x231 mm/kasan/report.c:188
__kasan_report.cold+0x1a/0x32 mm/kasan/report.c:317
kasan_report+0xe/0x20 mm/kasan/common.c:614
__lock_acquire+0x3a5d/0x5340 kernel/locking/lockdep.c:3665
lock_acquire+0x100/0x2b0 kernel/locking/lockdep.c:4303
__mutex_lock_common kernel/locking/mutex.c:926 [inline]
__mutex_lock+0xf9/0x12b0 kernel/locking/mutex.c:1073
device_release_driver_internal+0x23/0x4c0 drivers/base/dd.c:1109
bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:556
device_del+0x460/0xb80 drivers/base/core.c:2274
usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237
usb_disconnect+0x284/0x830 drivers/usb/core/hub.c:2199
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+0x13bd/0x3550 drivers/usb/core/hub.c:5441
process_one_work+0x905/0x1570 kernel/workqueue.c:2269
process_scheduled_works kernel/workqueue.c:2331 [inline]
worker_thread+0x7ab/0xe20 kernel/workqueue.c:2417
kthread+0x30b/0x410 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Allocated by task 89:
save_stack+0x1b/0x80 mm/kasan/common.c:71
set_track mm/kasan/common.c:79 [inline]
__kasan_kmalloc mm/kasan/common.c:489 [inline]
__kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:462
kmalloc include/linux/slab.h:547 [inline]
kzalloc include/linux/slab.h:742 [inline]
usb_set_configuration+0x2c4/0x1670 drivers/usb/core/message.c:1846
generic_probe+0x9d/0xd5 drivers/usb/core/generic.c:210
usb_probe_device+0x99/0x100 drivers/usb/core/driver.c:266
really_probe+0x281/0x660 drivers/base/dd.c:509
driver_probe_device+0x104/0x210 drivers/base/dd.c:670
__device_attach_driver+0x1c2/0x220 drivers/base/dd.c:777
bus_for_each_drv+0x15c/0x1e0 drivers/base/bus.c:454
__device_attach+0x217/0x360 drivers/base/dd.c:843
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514
device_add+0xae6/0x16f0 drivers/base/core.c:2111
usb_new_device.cold+0x6a4/0xe61 drivers/usb/core/hub.c:2536
hub_port_connect drivers/usb/core/hub.c:5098 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5213 [inline]
port_event drivers/usb/core/hub.c:5359 [inline]
hub_event+0x1abd/0x3550 drivers/usb/core/hub.c:5441
process_one_work+0x905/0x1570 kernel/workqueue.c:2269
worker_thread+0x96/0xe20 kernel/workqueue.c:2415
kthread+0x30b/0x410 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Freed by task 89:
save_stack+0x1b/0x80 mm/kasan/common.c:71
set_track mm/kasan/common.c:79 [inline]
__kasan_slab_free+0x130/0x180 mm/kasan/common.c:451
slab_free_hook mm/slub.c:1421 [inline]
slab_free_freelist_hook mm/slub.c:1448 [inline]
slab_free mm/slub.c:2994 [inline]
kfree+0xd7/0x280 mm/slub.c:3949
device_release+0x71/0x200 drivers/base/core.c:1064
kobject_cleanup lib/kobject.c:691 [inline]
kobject_release lib/kobject.c:720 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x171/0x280 lib/kobject.c:737
put_device+0x1b/0x30 drivers/base/core.c:2210
klist_put+0xce/0x170 lib/klist.c:221
bus_remove_device+0x3a4/0x4a0 drivers/base/bus.c:552
device_del+0x460/0xb80 drivers/base/core.c:2274
usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237
usb_disconnect+0x284/0x830 drivers/usb/core/hub.c:2199
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+0x13bd/0x3550 drivers/usb/core/hub.c:5441
process_one_work+0x905/0x1570 kernel/workqueue.c:2269
process_scheduled_works kernel/workqueue.c:2331 [inline]
worker_thread+0x7ab/0xe20 kernel/workqueue.c:2417
kthread+0x30b/0x410 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
The buggy address belongs to the object at ffff8881d4b1e600
which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 272 bytes inside of
2048-byte region [ffff8881d4b1e600, ffff8881d4b1ee00)
The buggy address belongs to the page:
page:ffffea000752c600 refcount:1 mapcount:0 mapping:ffff8881dac02800
index:0x0 compound_mapcount: 0
flags: 0x200000000010200(slab|head)
raw: 0200000000010200 ffffea0007536e00 0000000600000006 ffff8881dac02800
raw: 0000000000000000 00000000800f000f 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8881d4b1e600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881d4b1e680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881d4b1e700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8881d4b1e780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881d4b1e800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
Tested on:
commit: 6a3599ce 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=142eec8c600000
kernel config: https://syzkaller.appspot.com/x/.config?x=700ca426ab83faae
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
patch: https://syzkaller.appspot.com/x/patch.diff?x=15d95bf6600000
