Instant panic CAM or USB subsystem

[Steve Kargl]

On Tue, Jan 28, 2014 at 12:32:21PM -0500, John Baldwin wrote:
> On Saturday, January 25, 2014 12:21:06 pm Steve Kargl wrote:
> > If I plug my Samsung Intensity II cellphone into a usb port,
> > I get an instant panic.  This is 100% reproducible.  I have
> > the core and kernel for further debugging.  Dmesg.boot follows
> > my sig.
> > 
> > % kgdb /boot/kernel/kernel /vmcore.0
> > 
> > Unread portion of the kernel message buffer:
> > cd1 at umass-sim1 bus 1 scbus4 target 0 lun 0
> > cd1: <SAMSUNG CD-ROM 1.00> Removable CD-ROM SCSI-2 device 
> > cd1: Serial Number 000000000002
> > cd1: 1.000MB/s transfers
> > cd1: cd present [3840000 x 512 byte records]
> > cd1: quirks=0x10<10_BYTE_ONLY>
> > panic: mutex CAM device lock not owned at /usr/src/sys/cam/cam_periph.c:301
> > cpuid = 0
> > KDB: enter: panic
> 
> scsi@ might work better for this.  It looks like when cdasync() calls 
> cam_periph_alloc() it doesn't have its associated xpt_path locked.  All the 
> other async xpt callbacks I looked at don't lock the xpt path either.  It 
> seems they expect it to be locked by the caller when they are invoked.  It 
> seems xpt_async_process_dev() doesn't always lock xpt_lock, but sometimes
> locks the device instead:
> 
> 	/*
> 	 * If async for specific device is to be delivered to
> 	 * the wildcard client, take the specific device lock.
> 	 * XXX: We may need a way for client to specify it.
> 	 */
> 	if ((device->lun_id == CAM_LUN_WILDCARD &&
> 	     path->device->lun_id != CAM_LUN_WILDCARD) ||
> 	    (device->target->target_id == CAM_TARGET_WILDCARD &&
> 	     path->target->target_id != CAM_TARGET_WILDCARD) ||
> 	    (device->target->bus->path_id == CAM_BUS_WILDCARD &&
> 	     path->target->bus->path_id != CAM_BUS_WILDCARD)) {
> 		mtx_unlock(&device->device_mtx);
> 		xpt_path_lock(path);
> 		relock = 1;
> 	} else
> 		relock = 0;
> 
> 	(*(device->target->bus->xport->async))(async_code,
> 	    device->target->bus, device->target, device, async_arg);
> 	xpt_async_bcast(&device->asyncs, async_code, path, async_arg);
> 
> 	if (relock) {
> 		xpt_path_unlock(path);
> 		mtx_lock(&device->device_mtx);
> 	}
> 
> Maybe try going up to this frame (16) in your dump and do
> 'p *device->target'?  However, someone with more CAM knowledge needs to look 
> at this to see what is actually broken.
> 
> It seems a bit odd that it thinks your phone is a CD player.

Thanks for the follow-up.  I poked around a bit, but don't
recall looking at *device->target.   Under Windows, 3 
filesystems show up, and the one causing problems is listed
as CDFS.

I'm travaling this week for owrk, so may not be able to
follow-up with more info until Sunday.

-- 
Steve