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

[Alexander Nasonov <alnsn%yandex.ru@localhost>]

The following reply was made to PR kern/51714; it has been noted by GNATS.

From: Alexander Nasonov <alnsn%yandex.ru@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: kern-bug-people%netbsd.org@localhost, gnats-admin%netbsd.org@localhost,
	netbsd-bugs%netbsd.org@localhost
Subject: Re: kern/51714: uftdi (on xhci): mutex_vector_enter: locking against
 myself
Date: Sun, 12 Mar 2017 14:17:29 +0000

 coypu%sdf.org@localhost wrote:
 > >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.
 
 I can reliably reproduce the same panic on an idle box without
 detaching. Running
 
 # cu -s 115200 -l /dev/dtyU0
 
 always triggers the panic.
 
 
 NetBSD nebeda 7.99.46 NetBSD 7.99.46 (GENERIC) #0: Mon Dec 12 22:52:14
 GMT 2016
 alnsn@nebeda:/home/alnsn/netbsd-current/clean/src/sys/arch/amd64/compile/obj/GENERIC
 amd64
 
 uftdi0 at uhub0 port 3
 uftdi0: FTDI FT232R USB UART, rev 2.00/6.00, addr 2
 ucom0 at uftdi0 portno 1
 uftdi0: detached
 uftdi0: at uhub0 port 3 (addr 2) disconnected
 uftdi0 at uhub3 port 4
 uftdi0: FTDI FT232R USB UART, rev 2.00/6.00, addr 3
 ucom0 at uftdi0 portno 1
 uftdi_read() at netbsd:uftdi_read+0x3c
 uftdi0 at uhub3 port 4
 uftdi0: FTDI FT232R USB UART, rev 2.00/6.00, addr 3
 ucom0 at uftdi0 portno 1
 uftdi_read() at netbsd:uftdi_read+0x3c
 uftdi0 at uhub4 port 4
 uftdi0: FTDI FT232R USB UART, rev 2.00/6.00, addr 3
 ucom0 at uftdi0 portno 1
 
 panic: lock error: Mutex: mutex_vector_enter: locking against myself:
 lock 0xfffffe8107ceabb0 cpu 0 lwp 0xfffffe811f12c440
 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
 ehci_softintr() at netbsd:ehci_softintr+0x19c
 usb_soft_intr() at netbsd:usb_soft_intr+0x1f
 softint_dispatch() at netbsd:softint_dispatch+0xd3
 DDB lost frame for netbsd:Xsoftintr+0x4f, trying 0xfffffe80da664ff0
 Xsoftintr() at netbsd:Xsoftintr+0x4f
 --- interrupt ---
 0:
 cpu0: End traceback...
 uvm_fault(0xfffffe80887d68b0, 0x0, 2) -> e
 
 fatal page fault in supervisor mode
 dumping to dev 0,1 (offset=8601183, size=1022122):
 trap type 6 code 2 rip ffffffff808491bc cs 8 rflags 10286 cr2 84 ilevel
 8 rsp fffffe80aa567b20
 dump curlwp 0xfffffe8107ee9720 pid 6516.1 lowest kstack
 0xfffffe80aa5642c0
 
 
 I don't see this problem on a different box running a newer (7.99.59)
 kernel.
 
 Alex