Re: kern/49022: Locking issues in interaction of TTY and USB subsystems (exposed with uhso(4))

[Nick Hudson <skrll%netbsd.org@localhost>]

The following reply was made to PR kern/49022; it has been noted by GNATS.

From: Nick Hudson <skrll%netbsd.org@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: n54%gmx.com@localhost, kern-bug-people%netbsd.org@localhost, 
gnats-admin%netbsd.org@localhost, 
 netbsd-bugs%netbsd.org@localhost
Subject: Re: kern/49022: Locking issues in interaction of TTY and USB subsystems
 (exposed with uhso(4))
Date: Sun, 20 Jul 2014 12:19:14 +0100

 On 07/19/14 19:30, n54%gmx.com@localhost wrote:
 > #3 0xffffffff80770501 in lockdebug_abort1 (ld=0xffff800005989658, s=6,
 > func=0xffffffff80b40220 "lockdebug_barrier",
 > msg=0xffffffff80bf98de "spin lock held", dopanic=true)
 > at ../../../../kern/subr_lockdebug.c:783
 > #4 0xffffffff80539b1c in mutex_vector_enter (mtx=0xfffffe8006d1c010)
 > at ../../../../kern/kern_mutex.c:487
 > #5 0xffffffff802aacc2 in ehci_device_bulk_transfer (xfer=0xfffffe8006d69a10)
 > at ../../../../dev/usb/ehci.c:3547
 > #6 0xffffffff808473dc in usbd_transfer (xfer=0xfffffe8006d69a10)
 > at ../../../../dev/usb/usbdi.c:300
 > #7 0xffffffff80814fe2 in uhso_bulk_write (hp=0xfffffe80be282288)
 > at ../../../../dev/usb/uhso.c:1187
 > #8 0xffffffff80816bc6 in uhso_tty_start (tp=0xfffffe80be28c6c8)
 > at ../../../../dev/usb/uhso.c:1820
 > #9 0xffffffff807cb840 in ttstart (tp=0xfffffe80be28c6c8)
 > at ../../../../kern/tty.c:1680
 > #10 ttwrite (tp=0xfffffe80be28c6c8, uio=0xfffffe8007246de0,
 > flag=<optimized out>) at ../../../../kern/tty.c:2196
 
 tty_lock is held here...
 
     2196         ttstart(tp);
     2197         mutex_spin_exit(&tty_lock);
 
 http://nxr.netbsd.org/xref/src/sys/kern/tty.c#2196
 
 Nick