Hello,
syzbot found the following crash on:
HEAD commit: 4cc037ec usb: gadget: add raw-gadget interface
git tree: https://github.com/google/kasan.git usb-fuzzer
console output: https://syzkaller.appspot.com/x/log.txt?x=104e177ee00000
kernel config: https://syzkaller.appspot.com/x/.config?x=e9c2b6de462bc469
dashboard link: https://syzkaller.appspot.com/bug?extid=0b0095300dfeb8a83dc8
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=117f2fb1e00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16842d2ee00000
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+0b0095300dfeb8a83dc8@xxxxxxxxxxxxxxxxxxxxxxxxx
usb 1-1: USB disconnect, device number 2
==================================================================
BUG: KASAN: use-after-free in __media_entity_remove_links+0x134/0x160
drivers/media/mc/mc-entity.c:779
Read of size 8 at addr ffff8881d199f120 by task kworker/1:2/1719
CPU: 1 PID: 1719 Comm: kworker/1:2 Not tainted 5.5.0-rc1-syzkaller #0
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+0xef/0x16e lib/dump_stack.c:118
print_address_description.constprop.0+0x16/0x200 mm/kasan/report.c:374
__kasan_report.cold+0x37/0x7f mm/kasan/report.c:506
kasan_report+0xe/0x20 mm/kasan/common.c:639
__media_entity_remove_links+0x134/0x160 drivers/media/mc/mc-entity.c:779
__media_device_unregister_entity+0x187/0x300
drivers/media/mc/mc-device.c:596
media_device_unregister_entity+0x49/0x70 drivers/media/mc/mc-device.c:688
v4l2_device_unregister_subdev+0x257/0x380
drivers/media/v4l2-core/v4l2-device.c:283
v4l2_device_unregister drivers/media/v4l2-core/v4l2-device.c:100 [inline]
v4l2_device_unregister+0x139/0x220 drivers/media/v4l2-core/v4l2-device.c:88
uvc_unregister_video+0x11a/0x210 drivers/media/usb/uvc/uvc_driver.c:1929
uvc_disconnect+0xbc/0x160 drivers/media/usb/uvc/uvc_driver.c:2242
usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423
__device_release_driver drivers/base/dd.c:1134 [inline]
device_release_driver_internal+0x42f/0x500 drivers/base/dd.c:1165
bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:532
device_del+0x481/0xd30 drivers/base/core.c:2664
usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237
usb_disconnect+0x284/0x8d0 drivers/usb/core/hub.c:2200
hub_port_connect drivers/usb/core/hub.c:5035 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5324 [inline]
port_event drivers/usb/core/hub.c:5470 [inline]
hub_event+0x1753/0x3860 drivers/usb/core/hub.c:5552
process_one_work+0x92b/0x1530 kernel/workqueue.c:2264
worker_thread+0x96/0xe20 kernel/workqueue.c:2410
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Allocated by task 22:
save_stack+0x1b/0x80 mm/kasan/common.c:72
set_track mm/kasan/common.c:80 [inline]
__kasan_kmalloc mm/kasan/common.c:513 [inline]
__kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:486
kmalloc include/linux/slab.h:556 [inline]
kzalloc include/linux/slab.h:670 [inline]
media_add_link+0x47/0x180 drivers/media/mc/mc-entity.c:592
media_create_pad_link+0x1fb/0x530 drivers/media/mc/mc-entity.c:684
uvc_mc_create_links drivers/media/usb/uvc/uvc_entity.c:50 [inline]
uvc_mc_register_entities+0x468/0x77a drivers/media/usb/uvc/uvc_entity.c:114
uvc_register_chains drivers/media/usb/uvc/uvc_driver.c:2075 [inline]
uvc_probe.cold+0x2137/0x29de drivers/media/usb/uvc/uvc_driver.c:2201
usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361
really_probe+0x281/0x6d0 drivers/base/dd.c:548
driver_probe_device+0x104/0x210 drivers/base/dd.c:721
__device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430
__device_attach+0x217/0x360 drivers/base/dd.c:894
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490
device_add+0x1480/0x1c20 drivers/base/core.c:2487
usb_set_configuration+0xe67/0x1740 drivers/usb/core/message.c:2023
generic_probe+0x9d/0xd5 drivers/usb/core/generic.c:210
usb_probe_device+0x99/0x100 drivers/usb/core/driver.c:266
really_probe+0x281/0x6d0 drivers/base/dd.c:548
driver_probe_device+0x104/0x210 drivers/base/dd.c:721
__device_attach_driver+0x1c2/0x220 drivers/base/dd.c:828
bus_for_each_drv+0x162/0x1e0 drivers/base/bus.c:430
__device_attach+0x217/0x360 drivers/base/dd.c:894
bus_probe_device+0x1e4/0x290 drivers/base/bus.c:490
device_add+0x1480/0x1c20 drivers/base/core.c:2487
usb_new_device.cold+0x6a4/0xe79 drivers/usb/core/hub.c:2537
hub_port_connect drivers/usb/core/hub.c:5184 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5324 [inline]
port_event drivers/usb/core/hub.c:5470 [inline]
hub_event+0x1e59/0x3860 drivers/usb/core/hub.c:5552
process_one_work+0x92b/0x1530 kernel/workqueue.c:2264
worker_thread+0x96/0xe20 kernel/workqueue.c:2410
kthread+0x318/0x420 kernel/kthread.c:255
ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Freed by task 1719:
save_stack+0x1b/0x80 mm/kasan/common.c:72
set_track mm/kasan/common.c:80 [inline]
kasan_set_free_info mm/kasan/common.c:335 [inline]
__kasan_slab_free+0x129/0x170 mm/kasan/common.c:474
slab_free_hook mm/slub.c:1425 [inline]
slab_free_freelist_hook mm/slub.c:1458 [inline]
slab_free mm/slub.c:3005 [inline]
kfree+0xda/0x310 mm/slub.c:3957
__media_entity_remove_link+0x25c/0x5d0 drivers/media/mc/mc-entity.c:622
__media_entity_remove_links+0x86/0x160 drivers/media/mc/mc-entity.c:780
__media_device_unregister_entity+0x187/0x300
drivers/media/mc/mc-device.c:596
media_device_unregister_entity+0x49/0x70 drivers/media/mc/mc-device.c:688
v4l2_device_unregister_subdev+0x257/0x380
drivers/media/v4l2-core/v4l2-device.c:283
v4l2_device_unregister drivers/media/v4l2-core/v4l2-device.c:100 [inline]
v4l2_device_unregister+0x139/0x220 drivers/media/v4l2-core/v4l2-device.c:88
uvc_unregister_video+0x11a/0x210 drivers/media/usb/uvc/uvc_driver.c:1929
uvc_disconnect+0xbc/0x160 drivers/media/usb/uvc/uvc_driver.c:2242
usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:423
__device_release_driver drivers/base/dd.c:1134 [inline]
device_release_driver_internal+0x42f/0x500 drivers/base/dd.c:1165
bus_remove_device+0x2dc/0x4a0 drivers/base/bus.c:532
device_del+0x481/0xd30 drivers/base/core.c:2664
usb_disable_device+0x211/0x690 drivers/usb/core/message.c:1237
usb_disconnect+0x284/0x8d0 drivers/usb/core/hub.c:2200
hub_port_connect drivers/usb/core/hub.c:5035 [inline]
hub_port_connect_change drivers/usb/core/hub.c:5324 [inline]
port_event drivers/usb/core/hub.c:5470 [inline]
hub_event+0x1753/0x3860 drivers/usb/core/hub.c:5552
process_one_work+0x92b/0x1530 kernel/workqueue.c:2264
worker_thread+0x96/0xe20 kernel/workqueue.c:2410
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 ffff8881d199f100
which belongs to the cache kmalloc-96 of size 96
The buggy address is located 32 bytes inside of
96-byte region [ffff8881d199f100, ffff8881d199f160)
The buggy address belongs to the page:
page:ffffea00074667c0 refcount:1 mapcount:0 mapping:ffff8881da002f00
index:0xffff8881d199fe80
raw: 0200000000000200 ffffea0007474e40 0000000e0000000e ffff8881da002f00
raw: ffff8881d199fe80 0000000080200016 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8881d199f000: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
ffff8881d199f080: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
ffff8881d199f100: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
^
ffff8881d199f180: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
ffff8881d199f200: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
==================================================================
---
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