Re: Trouble booting PREEMPT_RT kernel on ARM platform, 2.6.33

[gowrishankar <gowrishankar.m@linux.vnet.ibm.com>]

On Wednesday 21 July 2010 03:56 AM, Jeremy Brown wrote:
> We're trying to get a PREEMPT_RT kernel running on a BeagleBoard C4
> (OMAP3 Arm architecture).  We're using kernel version 2.6.33, with
>    
2.6.33 ! not 2.6.33.6 ???
> patches from
> patch-2.6.33.6-rt26.gz
>
> On boot, we start seeing messages of this form:
>
> ----
> [ 4528.227294] BUG: sleeping function called from invalid context at
> kernel/rtmutex.c:684
> [ 4528.227294] pcnt: 1 0 in_atomic(): 1, irqs_disabled(): 128, pid:
> 223, name: modprobe
> [ 4528.227355] [<c0044490>] (unwind_backtrace+0x0/0xe8) from
> [<c04cb4e4>] (rt_spin_lock+0x30/0x5c)
> [ 4528.227386] [<c04cb4e4>] (rt_spin_lock+0x30/0x5c) from [<c032e3b0>]
> (twl4030_sih_set_type+0x3c/0xac)
>    
sleeping spin lock is called while preempt/interrupt is disabled.

Can you try the below patch ?

Signed-off-by: Gowrishankar <gowrishankar.m@in.ibm.com>

Index: linux-2.6.33.6-rt26/drivers/mfd/twl4030-irq.c
===================================================================
--- linux-2.6.33.6-rt26.orig/drivers/mfd/twl4030-irq.c    2010-07-21 
12:40:42.000000000 +0530
+++ linux-2.6.33.6-rt26/drivers/mfd/twl4030-irq.c    2010-07-21 
12:41:16.000000000 +0530
@@ -633,14 +633,14 @@
      if (trigger & ~(IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING))
          return -EINVAL;

-    spin_lock_irqsave(&sih_agent_lock, flags);
+    raw_spin_lock_irqsave(&sih_agent_lock, flags);
      if ((desc->status & IRQ_TYPE_SENSE_MASK) != trigger) {
          desc->status &= ~IRQ_TYPE_SENSE_MASK;
          desc->status |= trigger;
          sih->edge_change |= BIT(irq - sih->irq_base);
          queue_work(wq, &sih->edge_work);
      }
-    spin_unlock_irqrestore(&sih_agent_lock, flags);
+    raw_spin_unlock_irqrestore(&sih_agent_lock, flags);
      return 0;
  }

Thanks,
Gowri

> [ 4528.227416] [<c032e3b0>] (twl4030_sih_set_type+0x3c/0xac) from
> [<c00aa944>] (__irq_set_trigger+0x34/0x88)
> [ 4528.227447] [<c00aa944>] (__irq_set_trigger+0x34/0x88) from
> [<c00ab2ec>] (__setup_irq+0x34c/0x3c0)
> [ 4528.227478] [<c00ab2ec>] (__setup_irq+0x34c/0x3c0) from
> [<c00ab430>] (request_threaded_irq+0xd0/0x148)
> [ 4528.227508] [<c00ab430>] (request_threaded_irq+0xd0/0x148) from
> [<bf021770>] (twl_rtc_probe+0x104/0x1fc [rtc_twl])
> [ 4528.227539] [<bf021770>] (twl_rtc_probe+0x104/0x1fc [rtc_twl]) from
> [<c0324e2c>] (platform_drv_probe+0x18/0x1c)
> [ 4528.227569] [<c0324e2c>] (platform_drv_probe+0x18/0x1c) from
> [<c0323eec>] (driver_probe_device+0x98/0x194)
> [ 4528.227600] [<c0323eec>] (driver_probe_device+0x98/0x194) from
> [<c0324074>] (__driver_attach+0x8c/0x90)
> [ 4528.227600] [<c0324074>] (__driver_attach+0x8c/0x90) from
> [<c0323744>] (bus_for_each_dev+0x60/0x8c)
> [ 4528.227630] [<c0323744>] (bus_for_each_dev+0x60/0x8c) from
> [<c0323014>] (bus_add_driver+0xa0/0x240)
> [ 4528.227661] [<c0323014>] (bus_add_driver+0xa0/0x240) from
> [<c0324324>] (driver_register+0x78/0x13c)
> [ 4528.227661] [<c0324324>] (driver_register+0x78/0x13c) from
> [<c003e3c0>] (do_one_initcall+0x30/0x1c0)
> [ 4528.227691] [<c003e3c0>] (do_one_initcall+0x30/0x1c0) from
> [<c0097e40>] (sys_init_module+0xc4/0x1f8)
> [ 4528.227722] [<c0097e40>] (sys_init_module+0xc4/0x1f8) from
> [<c003ea60>] (ret_fast_syscall+0x0/0x2c)
> ---
>
> I'm hoping that someone will recognize this problem and be able to
> suggest a simple fix.  Any help would be very much appreciated!
>
> Thanks,
> Jeremy
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