Hello, syzbot found the following issue on: HEAD commit: b175d273 USB: legotower: fix logical error in recent commit git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing console output: https://syzkaller.appspot.com/x/log.txt?x=12ee7c87500000 kernel config: https://syzkaller.appspot.com/x/.config?x=d24ee9ecd7ce968e dashboard link: https://syzkaller.appspot.com/bug?extid=65be4277f3c489293939 compiler: gcc (GCC) 10.1.0-syz 20200507 Unfortunately, I don't have any reproducer for this issue yet. IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+65be4277f3c489293939@xxxxxxxxxxxxxxxxxxxxxxxxx usb 5-1: Direct firmware load for rtlwifi/rtl8192cufw.bin failed with error -2 rtlwifi: Loading alternative firmware rtlwifi/rtl8192cufw.bin rtlwifi: Selected firmware is not available ================================================================== BUG: KASAN: use-after-free in rtl_fw_do_work.cold+0x68/0x6a drivers/net/wireless/realtek/rtlwifi/core.c:93 Write of size 4 at addr ffff8881454cff50 by task kworker/0:6/7379 CPU: 0 PID: 7379 Comm: kworker/0:6 Not tainted 5.10.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events request_firmware_work_func Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x107/0x163 lib/dump_stack.c:118 print_address_description.constprop.0.cold+0xae/0x4c8 mm/kasan/report.c:385 __kasan_report mm/kasan/report.c:545 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:562 rtl_fw_do_work.cold+0x68/0x6a drivers/net/wireless/realtek/rtlwifi/core.c:93 request_firmware_work_func+0x12c/0x230 drivers/base/firmware_loader/main.c:1079 process_one_work+0x933/0x1520 kernel/workqueue.c:2272 worker_thread+0x64c/0x1120 kernel/workqueue.c:2418 kthread+0x38c/0x460 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 The buggy address belongs to the page: page:00000000f54435b3 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1454cf flags: 0x200000000000000() raw: 0200000000000000 0000000000000000 ffffea00051533c8 0000000000000000 raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881454cfe00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8881454cfe80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff8881454cff00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff8881454cff80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8881454d0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== --- This report 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 issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot.