BUG: scheduling while atomic

[dhylands@gmail.com (Dave Hylands)]

Hi Sandeep,

Sending to the list this time...

On Mon, May 9, 2011 at 10:51 PM, sandeep kumar
<coolsandyforyou@gmail.com> wrote:
> Here is the following logs i got when i collected ramdump from my
> development mobile after going to kernel panic
> Kernel version is 2.6.35.7, Android version GingerBread.
>
> BUG: scheduling while atomic: pppd/675/0x00000203
> <4>[?? 85.745849] Modules linked in: dhd hotspot_event_monitoring bthid
> cmc7xx_sdio
> <4>[?? 85.746032] [<c003f7dc>] (unwind_backtrace+0x0/0x168) from
> [<c05aa808>] (dump_stack+0x18/0x1c)
> <4>[?? 85.746154] [<c05aa808>] (dump_stack+0x18/0x1c) from [<c00d86a4>]
> (__schedule_bug+0x54/0x68)
> <4>[?? 85.746246] [<c00d86a4>] (__schedule_bug+0x54/0x68) from [<c05aab3c>]
> (schedule+0x78/0x48c)
> <4>[?? 85.746337] [<c05aab3c>] (schedule+0x78/0x48c) from [<c05ab604>]
> (schedule_timeout+0x24/0x23c)
> <4>[?? 85.746429] [<c05ab604>] (schedule_timeout+0x24/0x23c) from
> [<c05aced0>] (__down+0x88/0xc4)
> <4>[?? 85.746520] [<c05aced0>] (__down+0x88/0xc4) from [<c00fd654>]
> (down+0x44/0x84)
> <4>[?? 85.746643] [<c00fd654>] (down+0x44/0x84) from [<c0440bac>]
> (dpram_write+0x64/0x884)
> <4>[?? 85.746734] [<c0440bac>] (dpram_write+0x64/0x884) from [<c04414f0>]
> (vs_write+0x104/0x154)
> <4>[?? 85.746826] [<c04414f0>] (vs_write+0x104/0x154) from [<c034328c>]
> (ppp_async_push+0x110/0x584)
> <4>[?? 85.746917] [<c034328c>] (ppp_async_push+0x110/0x584) from
> [<c0343750>] (ppp_async_send+0x50/0x58)
> <4>[?? 85.747009] [<c0343750>] (ppp_async_send+0x50/0x58) from [<c0341360>]
> (ppp_channel_push+0x60/0x100)
> <4>[?? 85.747100] [<c0341360>] (ppp_channel_push+0x60/0x100) from
> [<c0341500>] (ppp_write+0x100/0x108)

Looking at the source, ppp_channel_push calls  spin_lock_bh which
enters the atomic context.

dpram_write tries to call down from within this context, which isn't legal.

-- 
Dave Hylands
Shuswap, BC, Canada
http://www.davehylands.com