bug in umass?

[Alexander Motin]

On 16.05.16 10:51, Hans Petter Selasky wrote:
> Hi Alexander,
> 
> Does dumping core on a USB stick from KDB require any threads?
> 
> From the USB point of view we are doing polling in "umass_cam_poll()".

CAM does not differentiate USB from others.  Kernel dumping completely
bypasses GEOM and its threads, manually pushes CAM queues without
requiring context switches, does polling for CAM HBA drivers via
respective method call, and processes completion queues without
depending on completion threads.

> On 05/16/16 07:02, K. Macy wrote:
>> I'm not able to complete a coredump in i915 to a USB key. The
>> backtrace in the log looks like a bug in umass.
>>
>>
>> May 15 21:57:10 beastie kernel: cmap[0]=0 cmap[1]=7f0000 cmap[2]=7f00
>> cmap[3]=c4a000
>> May 15 21:57:10 beastie kernel: end FB_INFO
>> May 15 21:57:10 beastie kernel: drmn0: fb0: inteldrmfb frame buffer
>> device
>> May 15 21:57:10 beastie kernel: ..3%
>> May 15 21:58:16 beastie syslogd: kernel boot file is /boot/kernel/kernel
>> May 15 21:58:16 beastie kernel: trap_fatal() at trap_fatal+0x2d/frame
>> 0xfffffe01e2fd6350
>> May 15 21:58:16 beastie kernel: trap() at trap+0xc48/frame
>> 0xfffffe01e2fd6690
>> May 15 21:58:16 beastie kernel: trap_check() at trap_check+0x4a/frame
>> 0xfffffe01e2fd66b0
>> May 15 21:58:16 beastie kernel: calltrap() at calltrap+0x8/frame
>> 0xfffffe01e2fd66b0
>> May 15 21:58:16 beastie kernel: --- trap 0x9, rip =
>> 0xffffffff80f5a950, rsp = 0xfffffe01e2fd6780, rbp = 0xfffffe01e2fd6810
>> ---
>> May 15 21:58:16 beastie kernel: __mtx_lock_flags() at
>> __mtx_lock_flags+0xd0/frame 0xfffffe01e2fd6810
>> May 15 21:58:16 beastie kernel: xpt_done_process() at
>> xpt_done_process+0x495/frame 0xfffffe01e2fd68c0
>> May 15 21:58:16 beastie kernel: xpt_done_td() at
>> xpt_done_td+0x1c0/frame 0xfffffe01e2fd6930
>> May 15 21:58:16 beastie kernel: fork_exit() at fork_exit+0x13b/frame
>> 0xfffffe01e2fd69b0
>> May 15 21:58:16 beastie kernel: fork_trampoline() at
>> fork_trampoline+0xe/frame 0xfffffe01e2fd69b0
>> May 15 21:58:16 beastie kernel: --- trap 0, rip = 0, rsp = 0, rbp = 0 ---
>>
> 


-- 
Alexander Motin