BUG: sleeping function called from invalid context at kernel/rtmutex.c:644

BUG: sleeping function called from invalid context at kernel/rtmutex.c:644

[Rosh shah]

Hi,

I have ported Davinci DM6467T support to the 2.6.33.9-rt for a
project. I am running into the following issue every time I run the
encode application gets a DMA interrupt. I have referred to the
various other instances of the same issue on older RT kernels, but
haven't gathered a solution for the same. Kindly help me understand
the issue / throw some light on how I can approach the solution.
Any thoughts are greatly appreciated.

Aug 16 14:44:01 dm6467t-evm user.debug kernel: dma complete  <INSERTED
BY B.J this is when the DMA ISR is called>
Aug 16 14:44:01 dm6467t-evm user.err kernel: BUG: sleeping function
called from invalid context at kernel/rtmutex.c:644
Aug 16 14:44:01 dm6467t-evm user.err kernel: pcnt: 0 0 in_atomic(): 0,
irqs_disabled(): 128, pid: 46, name: irq/16-edma
Aug 16 14:44:01 dm6467t-evm user.debug kernel: Backtrace:
Aug 16 14:44:01 dm6467t-evm user.debug kernel: [<c002f60c>]
(dump_backtrace+0x0/0x114) from [<c02feb38>] (dump_stack+0x18/0x1c)
Aug 16 14:44:01 dm6467t-evm user.debug kernel:  r7:00002068
r6:00002050 r5:00000000 r4:00000284
Aug 16 14:44:01 dm6467t-evm user.debug kernel: [<c02feb20>]
(dump_stack+0x0/0x1c) from [<c0039ae4>] (__might_sleep+0xfc/0x11c)
Aug 16 14:44:01 dm6467t-evm user.debug kernel: [<c00399e8>]
(__might_sleep+0x0/0x11c) from [<c03012e4>] (rt_spin_lock+0x38/0x64)
Aug 16 14:44:01 dm6467t-evm user.debug kernel:  r5:c20e6888 r4:c20e6888
Aug 16 14:44:01 dm6467t-evm user.debug kernel: [<c03012ac>]
(rt_spin_lock+0x0/0x64) from [<c0039378>] (complete+0x20/0x58)
Aug 16 14:44:01 dm6467t-evm user.debug kernel:  r5:c20e6888 r4:c20e6884
Aug 16 14:44:01 dm6467t-evm user.debug kernel: [<c0039358>]
(complete+0x0/0x58) from [<bf02f42c>] (dmaIsr+0x4c/0x70 [logos_tsif])
Aug 16 14:44:01 dm6467t-evm user.debug kernel:  r5:bf030930 r4:a0000013
Aug 16 14:44:01 dm6467t-evm user.debug kernel: [<bf02f3e0>]
(dmaIsr+0x0/0x70 [logos_tsif]) from [<c0035958>]
(dma_irq_handler+0x114/0x158)
Aug 16 14:44:01 dm6467t-evm user.debug kernel:  r5:00000005 r4:00000005
Aug 16 14:44:01 dm6467t-evm user.debug kernel: [<c0035844>]
(dma_irq_handler+0x0/0x158) from [<c006fd34>] (irq_thread+0xd4/0x238)
Aug 16 14:44:01 dm6467t-evm user.debug kernel: [<c006fc60>]
(irq_thread+0x0/0x238) from [<c005725c>] (kthread+0x88/0x90)
Aug 16 14:44:01 dm6467t-evm user.debug kernel: [<c00571d4>]
(kthread+0x0/0x90) from [<c0044990>] (do_exit+0x0/0x604)
Aug 16 14:44:01 dm6467t-evm user.debug kernel:  r7:00000000
r6:00000000 r5:00000000 r4:00000000

Please let me know if you need any other information regarding the
issue. Thanks a lot.

Best Regards,
Roshni
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Re: BUG: sleeping function called from invalid context at kernel/rtmutex.c:644

[Remy Bohmer]

Hi Roshni,

2011/8/18 Rosh shah <trinityrosh@gmail.com>:
> Hi,
>
> I have ported Davinci DM6467T support to the 2.6.33.9-rt for a
> project. I am running into the following issue every time I run the
> encode application gets a DMA interrupt. I have referred to the
> various other instances of the same issue on older RT kernels, but
> haven't gathered a solution for the same. Kindly help me understand
> the issue / throw some light on how I can approach the solution.
> Any thoughts are greatly appreciated.
>
> Aug 16 14:44:01 dm6467t-evm user.debug kernel: dma complete  <INSERTED
> BY B.J this is when the DMA ISR is called>
> Aug 16 14:44:01 dm6467t-evm user.err kernel: BUG: sleeping function
> called from invalid context at kernel/rtmutex.c:644

Looking at the backtrace, first guess: the dmaIsr() function tries to
call complete() with preemption and/or interrupts disabled.
In that case it runs into a regular spinlock that is converted to a
rt_mutex which, due to its nature, might sleep, which on its turn is
illegal in that context.

Kind regards,

Remy
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