fsl_udc_core: BUG: scheduling while atomic

fsl_udc_core: BUG: scheduling while atomic

[Matthew L. Creech]

Hi,

My MPC8313-based board, running a 2.6.37 kernel, is occasionally
hitting this bug while doing RNDIS-based communication:

BUG: scheduling while atomic: lighttpd/1145/0x10000200
Call Trace:
[c6a8b910] [c00086c0] show_stack+0x7c/0x194 (unreliable)
[c6a8b950] [c0019e28] __schedule_bug+0x54/0x68
[c6a8b960] [c02b04e8] schedule+0xa4/0x408
[c6a8ba50] [c02b0988] _cond_resched+0x38/0x64
[c6a8ba60] [c0080e8c] dma_pool_alloc+0x5c/0x2a4
[c6a8bac0] [c01c57b0] fsl_req_to_dtd+0x68/0x24c
[c6a8bb00] [c01c5b68] fsl_ep_queue+0x1d4/0x264
[c6a8bb20] [c01c7eec] eth_start_xmit+0x278/0x344
[c6a8bb50] [c01fdbc8] dev_hard_start_xmit+0x520/0x680
[c6a8bba0] [c02122a4] sch_direct_xmit+0x68/0x1e0
[c6a8bbc0] [c01fdf20] dev_queue_xmit+0x1f8/0x3c4
[c6a8bbe0] [c022d684] ip_finish_output+0x2d4/0x328
[c6a8bc10] [c022db08] ip_local_out+0x38/0x4c
[c6a8bc20] [c022e3cc] ip_queue_xmit+0x2cc/0x360
[c6a8bca0] [c0241844] tcp_transmit_skb+0x7cc/0x838
[c6a8bd00] [c0244434] tcp_write_xmit+0x8c4/0xa34
[c6a8bd60] [c0237618] tcp_sendmsg+0x900/0xbd4
[c6a8bdd0] [c0256088] inet_sendmsg+0x74/0x8c
[c6a8bdf0] [c01ea498] sock_aio_write+0x130/0x14c
[c6a8be50] [c00855fc] do_sync_write+0xb0/0x110
[c6a8bef0] [c0086294] vfs_write+0xdc/0x17c
[c6a8bf10] [c008642c] sys_write+0x54/0x9c
[c6a8bf40] [c000f2cc] ret_from_syscall+0x0/0x38

This seems similar to a bug from 2010:

http://www.spinics.net/lists/linux-usb/msg31354.html

which concludes that the fsl_udc_core driver is wrongly using
GFP_KERNEL in fsl_build_dtd().  However I'm not sure what an
appropriate fix is, since just replacing it with GFP_ATOMIC causes
allocation failures.  Any helpful tips?

Thanks

-- 
Matthew L. Creech

Re: fsl_udc_core: BUG: scheduling while atomic

[Sergej.Stepanov]

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Re: fsl_udc_core: BUG: scheduling while atomic

[Matthew L. Creech]

On Thu, May 12, 2011 at 4:37 AM,  <Sergej.Stepanov@ids.de> wrote:
> Hi Mattheew,
>
> such oops you can get also with spi.
> For such problem helps to compile your kernel with other preemption
> model:
> =A0- preempt
> =A0- standard
> =A0- !!! but not voluntary preemption !!!

Thanks Sergej, indeed I'm currently using CONFIG_PREEMPT_VOLUNTARY on
this board.  I'll change it to fix this problem for now.

Do you happen to know whether the Freescale folks intend to fix this?
If not, it seems like at least some sort of warning is in order.

--=20
Matthew L. Creech

Re: fsl_udc_core: BUG: scheduling while atomic

[Sergej.Stepanov]

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