Hi, all: I looked at the bug a little. The issue is that in the error handling code, hso_free_net_device unregisters the net_device (hso_net->net) by calling unregister_netdev. In the error handling code path, hso_net->net has not been registered yet. I think there are two ways to solve the issue: 1. fix it in drivers/net/usb/hso.c to avoiding unregistering the net_device when it is still not registered 2. fix it in unregister_netdev. We can add a field in net_device to record whether it is registered, and make unregister_netdev return if the net_device is not registered yet. What do you guys think ? On 9/3/19 8:08 AM, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: eea39f24 usb-fuzzer: main usb gadget fuzzer driver > git tree: https://github.com/google/kasan.git usb-fuzzer > console output: https://syzkaller.appspot.com/x/log.txt?x=15f17e61600000 > kernel config: > https://syzkaller.appspot.com/x/.config?x=d0c62209eedfd54e > dashboard link: > https://syzkaller.appspot.com/bug?extid=44d53c7255bb1aea22d2 > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > syz repro: > https://syzkaller.appspot.com/x/repro.syz?x=10ffdd12600000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15a738fe600000 > > IMPORTANT: if you fix the bug, please add the following tag to the > commit: > Reported-by: syzbot+44d53c7255bb1aea22d2@xxxxxxxxxxxxxxxxxxxxxxxxx > > usb 1-1: config 0 has no interface number 0 > usb 1-1: New USB device found, idVendor=0af0, idProduct=d257, > bcdDevice=4e.87 > usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0 > usb 1-1: config 0 descriptor?? > hso 1-1:0.15: Can't find BULK IN endpoint > ------------[ cut here ]------------ > WARNING: CPU: 1 PID: 83 at net/core/dev.c:8167 > rollback_registered_many.cold+0x41/0x1bc net/core/dev.c:8167 > Kernel panic - not syncing: panic_on_warn set ... > CPU: 1 PID: 83 Comm: kworker/1:2 Not tainted 5.3.0-rc5+ #28 > 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 > panic+0x2a3/0x6da kernel/panic.c:219 > __warn.cold+0x20/0x4a kernel/panic.c:576 > report_bug+0x262/0x2a0 lib/bug.c:186 > fixup_bug arch/x86/kernel/traps.c:179 [inline] > fixup_bug arch/x86/kernel/traps.c:174 [inline] > do_error_trap+0x12b/0x1e0 arch/x86/kernel/traps.c:272 > do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:291 > invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1028 > RIP: 0010:rollback_registered_many.cold+0x41/0x1bc net/core/dev.c:8167 > Code: ff e8 c7 26 90 fc 48 c7 c7 40 ec 63 86 e8 24 c8 7a fc 0f 0b e9 > 93 be ff ff e8 af 26 90 fc 48 c7 c7 40 ec 63 86 e8 0c c8 7a fc <0f> 0b > 4c 89 e7 e8 f9 12 34 fd 31 ff 41 89 c4 89 c6 e8 bd 27 90 fc > RSP: 0018:ffff8881d934f088 EFLAGS: 00010282 > RAX: 0000000000000024 RBX: ffff8881d2ad4400 RCX: 0000000000000000 > RDX: 0000000000000000 RSI: ffffffff81288cfd RDI: ffffed103b269e03 > RBP: ffff8881d934f1b8 R08: 0000000000000024 R09: fffffbfff11ad794 > R10: fffffbfff11ad793 R11: ffffffff88d6bc9f R12: ffff8881d2ad4470 > R13: ffff8881d934f148 R14: dffffc0000000000 R15: 0000000000000000 > rollback_registered+0xf2/0x1c0 net/core/dev.c:8243 > unregister_netdevice_queue net/core/dev.c:9290 [inline] > unregister_netdevice_queue+0x1d7/0x2b0 net/core/dev.c:9283 > unregister_netdevice include/linux/netdevice.h:2631 [inline] > unregister_netdev+0x18/0x20 net/core/dev.c:9331 > hso_free_net_device+0xff/0x300 drivers/net/usb/hso.c:2366 > hso_create_net_device+0x76d/0x9c0 drivers/net/usb/hso.c:2554 > hso_probe+0x28d/0x1a46 drivers/net/usb/hso.c:2931 > usb_probe_interface+0x305/0x7a0 drivers/usb/core/driver.c:361 > really_probe+0x281/0x6d0 drivers/base/dd.c:548 > driver_probe_device+0x101/0x1b0 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:454 > __device_attach+0x217/0x360 drivers/base/dd.c:894 > bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514 > device_add+0xae6/0x16f0 drivers/base/core.c:2165 > usb_set_configuration+0xdf6/0x1670 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+0x101/0x1b0 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:454 > __device_attach+0x217/0x360 drivers/base/dd.c:894 > bus_probe_device+0x1e4/0x290 drivers/base/bus.c:514 > device_add+0xae6/0x16f0 drivers/base/core.c:2165 > usb_new_device.cold+0x6a4/0xe79 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+0x1b5c/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 > Kernel Offset: disabled > Rebooting in 86400 seconds.. > > > --- > 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. > syzbot can test patches for this bug, for details see: > https://goo.gl/tpsmEJ#testing-patches
