usb/144423: if_run panic with USB-N13

[PseudoCylon]

The following reply was made to PR usb/144423; it has been noted by GNATS.

From: PseudoCylon <moonlightakkiy at yahoo.ca>
To: Hans Petter Selasky <hselasky at c2i.net>
Cc: bug-followup at freebsd.org, jhanna at pangolin-systems.com,
  freebsd-usb at freebsd.org, freebsd-gnats-submit at freebsd.org
Subject: Re: usb/144423: if_run panic with USB-N13
Date: Fri, 5 Mar 2010 03:40:05 -0800 (PST)

 ----- Original Message ----
 
 > From: Hans Petter Selasky <hselasky at c2i.net>
 > To: PseudoCylon <moonlightakkiy at yahoo.ca>
 > Cc: bug-followup at freebsd.org; jhanna at pangolin-systems.com; freebsd-usb at freebsd.org; freebsd-gnats-submit at freebsd.org
 > Sent: Fri, March 5, 2010 2:42:41 AM
 > Subject: Re: usb/144423: if_run panic with USB-N13
 > 
 > On Friday 05 March 2010 10:31:35 PseudoCylon wrote:
 > > >The files seem a little far from the current I am running, I just used
 > > >the updates to the usbdevs file and the unlock-lock around the firmware
 > > > load in if_run.c.
 > > 
 > > Yes, there are some bits added to support RT3572 chipsets. It would be
 > >  greately appreciated if you try that file if it's not too mutch trouble.
 > > 
 > > >The ASUS-N13 does work when a child wlan device is created with it,
 > > >but if just "ifconfig run0 up" is done there is a page fault. I do
 > > >not know if that is expected. This occurs with or without runfw.ko
 > > >being loaded beforehand.
 > > 
 > > Yes, "ifconfig run0 up" will cause page fault. The wlanN interface is
 > >  should be created as an instance of the parent interface and used for
 > >  actual communication. This is new feature to 8.0 and 9-current. My
 > >  understanding is that if you create wlan and "ifconfig *wlan0* up", it
 > >  works, but if you "ifconfig *run0* up", it causes panic. (Of cource
 > >  without *. I'm trying to enphasize the point in plain text messeage.) That
 > >  is what should happen. (Actually, result of "ifconfig *run0* up" is
 > >  undefined.) "run0" should only be used when creating wlan.
 > > 
 > > If "ifconfig *wlan0* ..." is causing problem, please let us know.
 > > 
 > 
 > What is the backtrace of the panic?
 KDB: stack backtrace:
 db_trace_self_wrapper() at db_trace_self_wrapper+0x2a
 _witness_debugger() at _witness_debugger+0x2e
 witness_warn() at witness_warn+0x2c2
 trap() at trap+0x2f5
 calltrap() at calltrap+0x8
 --- trap 0xc, rip = 0xffffffff80c5cfd7, rsp = 0xffffff8021f76880, rbp = 0xffffff8021f768c0 ---
 run_stop() at run_stop+0x67
 run_init_locked() at run_init_locked+0x33
 run_ioctl() at run_ioctl+0xad
 ifioctl() at ifioctl+0xde4
 kern_ioctl() at kern_ioctl+0xc5
 ioctl() at ioctl+0xf0
 syscall() at syscall+0x1af
 Xfast_syscall() at Xfast_syscall+0xe1
 --- syscall (54, FreeBSD ELF64, ioctl), rip = 0x800b8286c, rsp = 0x7fffffffe2f8, rbp = 0x7fffffffe300 ---
 
 There are number of places refers uninitialized value in run_stop() and run_init() if vap hasn't created, so it will cause page fault. I can move those instructions to other places (maybe vap_delete). It won't panic but device won't work without vap.
 
 
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