RT Kernel crash in SMP mode on Marvell board

[Manikandan Ramachandran]

Hello All,

   I'm trying to bring up a Marvell board [db644xx] with dual CPU[7447A]
with kernel 2.6.33.5-rt23[Ingo's RT patch]. For conveniance I have
registered IPI interrupt with IRQF_NODELAY flag, all other interrupts are
threaded. I'm able to boot up the system fine, however after few hours I see
random kernel crash in Marvell's PIC module. I understand that the RT kernel
doesn't like the way spinlock is used, I tried to convert to raw_spin_lock,
but the system would get frozen. I can make the system stable by just not
using any locks, but thats not an ideal solution. Can someone please suggest
a better locking mechanism? Crash dump I have given below:

NIP: 00000000 LR: 70030258 CTR: 00000000
REGS: deeebcf0 TRAP: 0400   Tainted: P            (2.6.33.5-rt23)
MSR: 40001032 <ME,IR,DR>  CR: 24004024  XER: 20000004
TASK = df915240[788] 'irq/74-ide0' THREAD: deeea000 CPU: 1
GPR00: 70030390 deeebda0 df915240 72e17ac0 703683f8 00000001 00000000
645d28e8
GPR08: 00000000 00000000 00000000 00000005 46f0b20f 00000000 00fe4600
007fff00
GPR16: 04000000 003d4ba2 007ffeb0 00800000 00ff690c 03000040 00f7eba2
deeebf6c
GPR24: 00000001 00000000 00000000 deeea000 72e17ac0 00000000 703683f8
703683f8
NIP [00000000] (null)
LR [70030258] enqueue_task+0x3c/0x58
Call Trace:
[deeebda0] [0000001e] 0x1e (unreliable)
[deeebdb0] [70030390] activate_task+0x40/0x60
[deeebdc0] [70036850] try_to_wake_up+0x248/0x334
[deeebe00] [70069380] wakeup_next_waiter+0x148/0x14c
[deeebe20] [7029b1d4] rt_spin_lock_slowunlock+0x60/0x84
[deeebe30] [7001a168] marvell_disable_IPI_irq+0xfc/0x110
[deeebe50] [70073934] handle_level_irq+0x40/0x15c
[deeebe70] [70006418] do_IRQ+0xc8/0xf4
[deeebe90] [7001276c] ret_from_except+0x0/0x14
--- Exception: 501 at schedule+0x30/0x50
    LR = schedule+0x24/0x50
[deeebf60] [700717bc] irq_thread+0x98/0x230
[deeebfa0] [7005686c] kthread+0x78/0x7c
[deeebff0] [70011ef4] kernel_thread+0x4c/0x68
Instruction dump:
XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX XXXXXXXX
Kernel panic - not syncing: Fatal exception in interrupt
Call Trace:
[deeebc20
---------------------------------------------------------------------------------------------------------------------

IRQ CONFIGs:

CONFIG_GENERIC_CMOS_UPDATE=y
CONFIG_GENERIC_TIME=y
CONFIG_GENERIC_TIME_VSYSCALL=y
CONFIG_GENERIC_CLOCKEVENTS=y
CONFIG_GENERIC_HARDIRQS=y
CONFIG_GENERIC_HARDIRQS_NO__DO_IRQ=y
# CONFIG_HAVE_SETUP_PER_CPU_AREA is not set
# CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK is not set
CONFIG_IRQ_PER_CPU=y
CONFIG_NR_IRQS=512
CONFIG_STACKTRACE_SUPPORT=y
CONFIG_HAVE_LATENCYTOP_SUPPORT=y
CONFIG_TRACE_IRQFLAGS_SUPPORT=y

-- 
Thanks,
Manik

Think twice about a tree before you take a printout
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