Re: [Xenomai-help] kernel BUG in preempt_schedule_irq at kernel/sched.c:3114!

[Philippe Gerum <rpm@xenomai.org>]

Yigal Goldberger wrote:
> Hi, 
> I've also submitted this on the website under Xenomai-support, but I'm not sure which is the best way to go... so I'll try this channel as well.
>

This channel is the best one for now.

> My system is a PPC running kernel 2.6.14.7 patched with Xenomai. 
> My system communicates with the host PC through two RS-232 ports and each port has also a uart connection to a slave device. 
> The slave device sends interrupts to the CPU on the board , and are handled by a lodable kernel module interrupt handler . 
> When the system works only through a singel port - (RS-232 between the PC and the board,and uart between the board and a slave device) it works fine, but when the 2 ports are stressed together I get the Oops below.I've tried working with the uart without interrupts and the Oops still occures . 
> 
> 
> I've looked it up in the System.map file and the addresses correspond to the following : 
> c0004c7c - __ipipe_ret_from_except 
> c0004a40 - somewhere inside resume_kernel. 
> 
> 
> " kernel BUG in preempt_schedule_irq at kernel/sched.c:3114! 
> Oops: Exception in kernel mode, sig: 5 [#1] 
> PREEMPT 
> NIP: C02297A8 LR: C0004A40 SP: C0286170 REGS: c02860c0 TRAP: 0700 Tainted: P 
> MSR: 00029032 EE: 1 PR: 0 FP: 0 ME: 1 IR/DR: 11 
> TASK = c0265b00[0] 'swapper' THREAD: c0286000 
> Last syscall: 120 
> GPR00: 00000001 C0286170 C0265B00 00009032 00000000 00003032 00600084 C02B5594 
> GPR08: C0280000 C0286000 00000001 C026A200 512037AD 4377FFBF 0FFFD000 00000000 
> GPR16: 00000001 00000001 FFFFFFFF 007FFF00 0FFF7E68 00000000 00000002 0FBC62B0 
> GPR24: 00000000 00000000 40000000 007FFF7D 007FFF00 C02A0000 C0265B00 C02A28F0 
> Call trace: [c0004a40] [c0004c7c] [c0004c7c] [c0004c7c] [c0004c7c] [c0004c7c] [c0004c7c] [c0004c7c] [c0004c7c] [c0004c7c] [c0004c7c] [c0004c7c] [c0004c7c] [c0004c7c] [c0004c7c] 
> Kernel panic - not syncing: Attempted to kill the idle task! 
> <0>Rebooting in 1 seconds..þ " 
> 
> 
> Does anyone have an idea why this is happening and what am I doing wrong ? 
> 

Your kernel is outdated. I-pipe patches for 2.6.14 were not fully PREEMPT-safe. 
Disable CONFIG_PREEMPT and try again, but there is no guarantee you won't face 
other issues that have been fixed in the I-pipe support for recent kernels. 
2.6.20 is the oldest release that I would recommend for running a powerpc 
plateform w/ Xenomai over the Linux 2.6.x series; earlier I-pipe patches for 
2.6.x/powerpc may have stability and performances issues.

> 
> Thanks, 
> Yigal. 
> 
> 
> 
> 
>       
> 
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-- 
Philippe.