BUG: scheduling while atomic

Hi Arun,

On Wed, Apr 18, 2012 at 1:58 AM, Arun KS [off-list ref] wrote:

On Wed, Apr 18, 2012 at 12:14 PM, Arun KS [off-list ref] wrote:

quoted

Hello Guys,

System is working normal after this BUG.
PC is at 0x400b4614, probably a mmaped address.

Just wondering how can this BUG happen when a process is running in user
space.


Can it be something like this
1) enter to kernel from userspace through some system call.
2) kernel disables the interrupt and return to user space.
3) and now it can happen in user space?

Any thoughts?

shell at android: # ls
device[?? 40.603515] BUG: scheduling while atomic: Binder Thread
#/1355/0x00010003
[?? 40.610290] Modules linked in:
[?? 40.613342]
[?? 40.614837] Pid: 1355, comm:????? Binder Thread #
[?? 40.619506] CPU: 0??? Tainted: G??????? W??? (3.0.15+ #174)
[?? 40.625061] PC is at 0x400b4614
[?? 40.628173] LR is at 0x408d83c9
[?? 40.631317] pc : [<400b4614>]??? lr : [<408d83c9>]??? psr: 40000010
[?? 40.631317] sp : 50551918? ip : 4092d1c0? fp : 505519a4
[?? 40.642730] r10: 50551974? r9 : 5016de28? r8 : 1f600009
[?? 40.647949] r7 : 00000000? r6 : 00000000? r5 : 5055194c? r4 : 00f09f90
[?? 40.654418] r3 : 40931c58? r2 : 00000000? r1 : 00f09f90? r0 : 00000006
[?? 40.660919] Flags: nZcv? IRQs on? FIQs on? Mode USER_32? ISA ARM
Segment user

But if you look at the flags here,? it is showing that IRQs are on.

quoted

[?? 40.668121] Control: 10c53c7d? Table: 91184059? DAC: 00000015

So, an atomic context, as far as the kernel is concerned, also
includes disabling preemption, not just disabling interrupts.

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