kern/51714: uftdi (on xhci): mutex_vector_enter: locking against myself

[coypu%sdf.org@localhost]

>Number:         51714
>Category:       kern
>Synopsis:       uftdi (on xhci): mutex_vector_enter: locking against myself
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Dec 13 19:30:02 +0000 2016
>Originator:     coypu
>Release:        NetBSD 7.99.46
>Organization:
>Environment:
NetBSD box 7.99.46 NetBSD 7.99.46 (GENERIC) #3: Mon Dec 12 21:01:23 IST 2016  fly@box:/home/fly/gcc/sys/arch/amd64/compile/GENERIC amd64
>Description:
"Heavy load" (I was using 'while true; do dmesg; done' on the target machine) & killing cu / detaching cable.

Backtrace:

uhub0 at usb0: vendor 8086 xHCI Root Hub, class 9/0, rev 1.00/1.00, addr 0
uhub0: 21 ports with 21 removable, self powered
:
uhub3 at uhub0 port 9: vendor 045b product 0209, class 9/0, rev 2.10/1.00, addr 1
uhub3: single transaction translator
uhub3: 4 ports with 4 removable, self powered
:
uftdi0 at uhub3 port 2
uftdi0: FTDI FT232R USB UART, rev 2.00/6.00, addr 5
ucom0 at uftdi0 portno 1
panic: lock error: Mutex: mutex_vector_enter: locking against myself: lock 0xfffffe845c8b02b0 cpu 0 lwp 0xfffffe847ef32440
cpu0: Begin traceback...
vpanic() at netbsd:vpanic+0x140
snprintf() at netbsd:snprintf
lockdebug_abort() at netbsd:lockdebug_abort+0x63
mutex_vector_enter() at netbsd:mutex_vector_enter+0x369
ucom_status_change() at netbsd:ucom_status_change+0x52
uftdi_read() at netbsd:uftdi_read+0x3c
ucomreadcb() at netbsd:ucomreadcb+0x183
usb_transfer_complete() at netbsd:usb_transfer_complete+0x149
xhci_softintr() at netbsd:xhci_softintr+0x402
usb_soft_intr() at netbsd:usb_soft_intr+0x1f
softint_dispatch() at netbsd:softint_dispatch+0xd3
DDB lost frame for netbsd:Xsoftintr+0x4f, trying 0xfffffe811cdd3ff0
Xsoftintr() at netbsd:Xsoftintr+0x4f
--- interrupt ---
0:
cpu0: End traceback...
uvm_fault(0xfffffe8124c405e0, 0x0, 2) -> e
fatal page fault in supervisor mode
trap type 6 code 2 rip ffffffff808491bc cs 8 rflags 10286 cr2 84 ilevel 8 rsp fffffe812889edd0
curlwp 0xfffffe843a6f9260 pid 1971.43 lowest kstack 0xfffffe812889b2c0

dumping to dev 0,1 (offset=8, size=4150227):
dump

Second backtrace:


>How-To-Repeat:

>Fix: