Bugs in the Raspberry Pi BSP

Alan Cudmore alan.cudmore at gmail.com
Mon Apr 8 15:19:02 UTC 2013

I will check to see if the clock driver is enabled and running, that sounds
like a good place to start.
I would think that the context switching, stacks, and memory map are OK due
to the number of other things that work. ( I modified unlimited to create
10,000 tasks )

Also, I found some good info on low cost JTAG options for the Pi:


On Mon, Apr 8, 2013 at 10:49 AM, Joel Sherrill <joel.sherrill at oarcorp.com>wrote:

> On 4/8/2013 9:22 AM, Alan Cudmore wrote:
>> This weekend, I was putting together an example for the Raspberry Pi
>> which includes a ramdisk, nvramdisk, shell with most commands enabled, and
>> a few of the samples built in.
>> While much of the code I run works, I have run into a few problems.
>> Some examples:
>> 1. If I type "ls" on the shell, it works. If I type "ls -l" the shell (
>> and I guess the board ) locks up. I could probably start some tasks to see
>> if it's just the shell that stops.
>> 2. If I type in an incorrect command like "helo" rather than "help" the
>> shell will lock up.
>> 3. If I try to copy a file "cp shell-init shell-init2"  The shell seems
>> to lock up. This is in the base imfs file system.
>>  (2) looks like a very easy and suspicious case. The command lookup is a
> simple
> search of a list after splitting the command line into argc/argv. From
> shell_cmdset.c:
> rtems_shell_cmd_t * rtems_shell_lookup_cmd(const char * cmd) {
>   rtems_shell_cmd_t * shell_cmd;
>   shell_cmd=rtems_shell_first_**cmd;
>   while (shell_cmd) {
>    if (!strcmp(shell_cmd->name,cmd)) return shell_cmd;
>    shell_cmd=shell_cmd->next;
>   };
>   return NULL;
> }
> Notice that it depends on finding a NULL at the end of the list of
> commands.
> I am guessing you don't have a NULL there and the question
> is why.
> strcmp is also dangerous given that it is processing arbitrary
> user input. But you aren't pushing a buffer overflow here.
>  But many other things still work. I can create a 32MB ramdisk, format it
>> with RFS, mount it and fill it up with test files. I was even able to copy
>> a file on the RFS ramdisk.
>> I was thinking that the shell issues might be due to a very basic polled
>> console driver. It might not be behaving the way a proper termios
>> compatible console driver should.
>>  It is using the libchip console framework and thus is using termios.
> You have to have the clock tick device driver running though since if
> you don't have input, then the termios polled code will sleep for 1
> tick.
> If you forgot to enable the clock driver on cases with user input,
> this would lock the system up.
>  I think it's time to get a jtag setup for this board because I really
>> cannot tell what is going on.
>> Alan
> --
> Joel Sherrill, Ph.D.             Director of Research & Development
> joel.sherrill at OARcorp.com        On-Line Applications Research
> Ask me about RTEMS: a free RTOS  Huntsville AL 35805
> Support Available                (256) 722-9985
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.rtems.org/pipermail/users/attachments/20130408/188fd222/attachment-0001.html>

More information about the users mailing list