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Re: [microblaze-uclinux] Trace/BPT trap message
Hi Leonid,
Leonid wrote:
What does this message mean? I started to see it with no particular
reason - I just run process, sending packet via UDS socket to another
process, waiting for response, printing message's content and leaving:
This message is generated by the shell (probably busybox's msh in this
case?), when the shell is doing a wait_for_child() operation. It prints
out the name of the signal that caused the death of the child process.
In this case, it's signal 5 - SIGTRAP.
SIGTRAP is generated by the kernel if a process executes a breakpoint
trap - in MicroBlaze this is "brki r14, 0x60". This shouldn't happen
unless you are using gdbserver to debug it, or doing something tricky
with the ptrace() system call.
It's possible your app has gone diving off to random memory, ended up
executing the 0x60 breakpoint trap. No handler was installed, so it died
and the shell reported that fact.
You might try using XMD to set a hardware breakpoint at 0x60, boot the
kernel and run your app. When (if?) the HW stops at 0x60, look at the
registers and try to see how it got there. r15 is the link register,
that should tell you the address of the last branch instruction
(function call) taken. If you're really lucky, r14 will contain the
address of a "brki r14, 0x60" debug trap instruction that is causing the
trap.
Cross reference these addresses back into a kernel object dump
$ microblaze-uclinux-objdump -S linux-2.4.x/linux > linux.dump
I think you'll need to get a bit forensic on this one.
Regards,
John
# /home/httpd/cgi-bin/cgi_server
# Test Script Name Steps Curr Prcnt ENBL RUN Loops Usage Cntr
--------------------------------------------------------------
1 LEDs_Walk 12 12 100 + - 1 1
1 Module_ID 6 6 100 + - 1 1
2 FPGA_SDRAM 5 5 100 + - 1 1
3 NOR_FLASH 5 5 100 + - 1 1
4 GPIO_SAMPLE 4 4 100 + - 1 1
5 GPIO_WALK_0 32 32 100 + - 1 1
6 GPIO_WALK_1 32 32 100 + - 1 1
7 ETH_PING 1 1 100 + - 1 1
8 CAN_GPIO 2 2 100 + - 1 1
9 MIL_1553_SAMPLE 4 4 100 + - 1 1
Trace/BPT trap
Could be some memory violation?
Thanks,
Leonid.
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