On 1/29/21 7:25 PM, Tetsuo Handa wrote:

On 2021/01/30 6:18, Shuah Khan wrote:

quoted

In this console log:

It seems "this console log" refers to https://syzkaller.appspot.com/x/log.txt?x=10453034500000 .

quoted

06:57:50 executing program 1:
socketpair$tipc(0x1e, 0x2, 0x0, &(0x7f00000000c0)={<r0=>0xffffffffffffffff})
sendmsg$BATADV_CMD_GET_TRANSTABLE_LOCAL(r0, &(0x7f00000002c0)={&(0x7f00000001c0), 0xc, &(0x7f0000000280)={0x0, 0xd001010000000000}}, 0x0)

[ 1151.090883][T23361] vhci_hcd vhci_hcd.0: pdev(4) rhport(0) sockfd(4)
[ 1151.097445][T23361] vhci_hcd vhci_hcd.0: devid(0) speed(1) speed_str(low-speed)
06:57:50 executing program 0:
r0 = syz_open_dev$binderN(&(0x7f0000000680)='/dev/binder#\x00', 0x0, 0x0)
ioctl$BINDER_WRITE_READ(r0, 0xc0306201, &(0x7f0000000cc0)={0x88, 0x0, &(0x7f0000000b80)=[@transaction={0x40406300, {0x2, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}}, @transaction={0x40406300, {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}}], 0x0, 0x0, 0x0})

[ 1151.164402][T23363] vhci_hcd: connection closed
[ 1151.167346][  T240] vhci_hcd: stop threads


[ 1151.178329][T26761] usb 17-1: new low-speed USB device number 2 using vhci_hcd


SK: Looking at the console log, it looks like while connection is being
     torn down,

Excuse me, but it looks like (what comes here) while connection is being torn down ?
I'm not familiar with driver code.

quoted

[ 1151.181245][  T240] vhci_hcd: release socket


Can you share your your test code for this program:
"executing program 1"

I don't think program 1 is relevant. I think program 4

   06:57:50 executing program 4:
   r0 = socket$tipc(0x1e, 0x2, 0x0)
   syz_usbip_server_init(0x1)
   close_range(r0, 0xffffffffffffffff, 0x0)

which calls syz_usbip_server_init() as with other duplicates is relevant.

quoted

Also your setup? Do you run usbip_host and vhci_hcd both?

Who are you referring to with "you/your" ? I'm not running syzkaller in my setup
and I don't have test code.

I'm just proposing printing more messages in order to confirm the ordering of
events and member values in structures.

I am looking to understand the syzbot configuration and a reproducer
to be able to debug and fix the problem. How is syzbot triggering the
vhci_hcd attach and detach sequence?

This helps me determine all these fix suggestions that are coming in
are fixes or papering over a real problem.

thanks,
-- Shuah