I'm running 3.6.11-rt31 on a Raspberry Pi. Running cyclictest like this: sudo ./cyclictest -p95 -m -W -b 1000 # /dev/cpu_dma_latency set to 0us policy: fifo: loadavg: 0.72 0.28 0.10 2/137 2054 causes this: Entering kdb (current=0xca78e0a0, pid 2058) Oops: (null) due to oops @ 0xc009f654 Pid: 2058, comm: cyclictest CPU: 0 Not tainted (3.6.11-rt31+ #10) PC is at ring_buffer_lock_reserve+0x7c/0x144 LR is at ftrace_test_stop_func+0x28/0x34 pc : [<c009f654>] lr : [<c0097684>] psr: 600001d1 sp : ca7bfa78 ip : ca7bfaf0 fp : ca7bfaec r10: 00000000 r9 : c088ece0 r8 : ca7be000 r7 : 200001d1 r6 : c030dd28 r5 : c00ab928 r4 : c0786000 r3 : 200001d1 r2 : 00000018 r1 : 00000000 r0 : cb8013a0 Flags: nZCv IRQs off FIQs off Mode FIQ_32 ISA ARM Segment user Control: 00c5387d Table: 0a7b8008 DAC: 00000015 [<c0015188>] (unwind_backtrace+0x0/0xfc) from [<c041953c>] (dump_stack+0x20/0x24) [<c041953c>] (dump_stack+0x20/0x24) from [<c000f720>] (show_regs+0x4c/0x58) [<c000f720>] (show_regs+0x4c/0x58) from [<c0086c48>] (kdb_dumpregs+0x38/0x60) [<c0086c48>] (kdb_dumpregs+0x38/0x60) from [<c00897d8>] (kdb_main_loop+0x348/0x77c) [<c00897d8>] (kdb_main_loop+0x348/0x77c) from [<c008c3d8>] (kdb_stub+0x2f0/0x3f8) [<c008c3d8>] (kdb_stub+0x2f0/0x3f8) from [<c0082b24>] (kgdb_handle_exception+0x164/0x6fc) [<c0082b24>] (kgdb_handle_exception+0x164/0x6fc) from [<c00147e0>] (kgdb_notify+0x3c/0x74) [<c00147e0>] (kgdb_notify+0x3c/0x74) from [<c0421e84>] (notifier_call_chain+0x54/0x94) [<c0421e84>] (notifier_call_chain+0x54/0x94) from [<c0421f0c>] (__atomic_notifier_call_chain+0x48/0x5c) [<c0421f0c>] (__atomic_notifier_call_chain+0x48/0x5c) from [<c0421f48>] (atomic_notifier_call_chain+0x28/0x30) [<c0421f48>] (atomic_notifier_call_chain+0x28/0x30) from [<c0421f90>] (notify_die+0x40/0x4c) [<c0421f90>] (notify_die+0x40/0x4c) from [<c0011de8>] (die+0xd8/0x3c0) [<c0011de8>] (die+0xd8/0x3c0) from [<c0012480>] (bad_mode+0x4c/0x70) [<c0012480>] (bad_mode+0x4c/0x70) from [<c0097684>] (ftrace_test_stop_func+0x28/0x34) AFAICT, this is actually kgdb encountering a problem while trying to unwind the stack trace from the real problem - is that right? The problem seems to be caused by cyclictest setting up the tracer, not triggering it - it doesn't matter what I set the latency threshold to, the same thing happens. Is there a known cause for this? Any tips on how to start debugging it? Thanks, Tom -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
