Hello, syzbot found the following crash on: HEAD commit: 806d8acc USB: dummy-hcd: use configurable endpoint naming .. git tree: https://github.com/google/kasan.git usb-fuzzer console output: https://syzkaller.appspot.com/x/log.txt?x=161ad202100000 kernel config: https://syzkaller.appspot.com/x/.config?x=d800e9bad158025f dashboard link: https://syzkaller.appspot.com/bug?extid=83803be25e647b7e40b0 compiler: gcc (GCC) 9.0.0 20181231 (experimental) Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+83803be25e647b7e40b0@xxxxxxxxxxxxxxxxxxxxxxxxx em28xx 2-1:0.63: Closing input extension ================================================================== BUG: KASAN: use-after-free in media_device_unregister drivers/media/mc/mc-device.c:822 [inline] BUG: KASAN: use-after-free in media_device_unregister+0x564/0x5d0 drivers/media/mc/mc-device.c:800 Read of size 8 at addr ffff8881ccf74210 by task kworker/1:7/3751 CPU: 1 PID: 3751 Comm: kworker/1:7 Not tainted 5.7.0-rc5-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.cold+0xd3/0x314 mm/kasan/report.c:382 __kasan_report.cold+0x37/0x92 mm/kasan/report.c:511 kasan_report+0x33/0x50 mm/kasan/common.c:625 media_device_unregister drivers/media/mc/mc-device.c:822 [inline] media_device_unregister+0x564/0x5d0 drivers/media/mc/mc-device.c:800 em28xx_unregister_media_device drivers/media/usb/em28xx/em28xx-cards.c:3392 [inline] em28xx_release_resources+0xaf/0x254 drivers/media/usb/em28xx/em28xx-cards.c:3413 em28xx_usb_disconnect.cold+0x18b/0x284 drivers/media/usb/em28xx/em28xx-cards.c:4072 usb_unbind_interface+0x1bd/0x8a0 drivers/usb/core/driver.c:436 __device_release_driver drivers/base/dd.c:1110 [inline] device_release_driver_internal+0x432/0x500 drivers/base/dd.c:1141 bus_remove_device+0x2eb/0x5a0 drivers/base/bus.c:533 device_del+0x481/0xd30 drivers/base/core.c:2715 usb_disable_device+0x23d/0x790 drivers/usb/core/message.c:1245 usb_disconnect+0x293/0x900 drivers/usb/core/hub.c:2216 hub_port_connect drivers/usb/core/hub.c:5058 [inline] hub_port_connect_change drivers/usb/core/hub.c:5347 [inline] port_event drivers/usb/core/hub.c:5493 [inline] hub_event+0x1abf/0x43c0 drivers/usb/core/hub.c:5575 process_one_work+0x965/0x1630 kernel/workqueue.c:2268 process_scheduled_works kernel/workqueue.c:2330 [inline] worker_thread+0x7ab/0xe20 kernel/workqueue.c:2416 kthread+0x326/0x430 kernel/kthread.c:268 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:351 The buggy address belongs to the page: page:ffffea000733dd00 refcount:0 mapcount:-128 mapping:00000000f4330ebd index:0x0 flags: 0x200000000000000() raw: 0200000000000000 ffffea00071b0808 ffff88821fffabd0 0000000000000000 raw: 0000000000000000 0000000000000002 00000000ffffff7f 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881ccf74100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8881ccf74180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff8881ccf74200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff8881ccf74280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8881ccf74300: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
