Re: [Discuss-gnuradio] gnuradio on ARM: gr_vmcircbuf_sysv_shm: shmat (3): Invalid argument

[Philip Balister]

On 04/17/2013 07:28 PM, Monahan-Mitchell, Tim wrote:
> gnuradio maint branch, v.3.6.4.1
> 
> 'make test' fails, due to gr-core-test-all failing.
> 
> At first, I was getting an error due to the "shmat (2)" line above where this 
> error occurs, but it has settled on (3).
> I added a couple lines of extra debug output (source code is below the error 
> output).

I am digging into repressed memories here, so people cirrect me if I am
wrong.

GNU Radio allocates a large buffer to use for block input/output
buffers. It has about three ways to do this, one of which uses shmem
calls. These calls fail on arm due to some internal difference between
x86 and arm. (I forget what the detail is)

Since this fails, it tries another allocator that succeeds and saves
this info in a dot file. I think you see the message from gnuradio once,
then you do not see it again.

Philip

> 
> test 6
>         Start   6: gr-core-test-all
> 
> 6: Test command: /bin/sh 
> "/src/gnuradio/build/gnuradio-core/src/tests/gr-core-test-all_test.sh"
> 6: Test timeout computed to be: 9.99988e+06
> 6: Testing gr_vmcircbuf_createfilemapping_factory...
> 6: gr_vmcircbuf_createfilemapping: createfilemapping is not available
> 6: ....... gr_vmcircbuf_createfilemapping_factory: Doesn't work
> 6: Testing gr_vmcircbuf_sysv_shm_factory...
> 6: gr_vmcircbuf_sysv_shm: shmat (3): Invalid argument
> 6: gr_vmcircbuf_sysv_shm: shmid1=163842, first_copy+pagesize=0x40039000
> 6: ....... gr_vmcircbuf_sysv_shm_factory: Doesn't work
> 6: Testing gr_vmcircbuf_mmap_shm_open_factory...
> 6: ....... gr_vmcircbuf_mmap_shm_open_factory: OK
> 6: Testing gr_vmcircbuf_mmap_tmpfile_factory...
> 6: ....... gr_vmcircbuf_mmap_tmpfile_factory: OK
> 6: ...........................NOTICE: test from c++ NOTICE
> 6: DEBUG: test from c++ DEBUG
> 6: INFO: test from c++ INFO
> 6: WARN: test from c++ WARN
> 6: ERROR: test from c++ ERROR
> 6: FATAL: test from c++ FATAL
> 6: .....Using Volk machine: generic
> 
> Snippet from gr_vmcircbuf_sysv_shm.cc :
> 
>   // There may be a race between our detach and attach.
>   //
>   // If the system allocates all shared memory segments at the same
>   // virtual addresses in all processes and if the system allocates
>   // some other segment to first_copy or first_copoy + size between
>   // our detach and attach, the attaches below could fail [I've never
>   // seen it fail for this reason].
> 
>   //shmdt (first_copy);
> 
>   if (shmdt (first_copy) == -1){
>     perror("gr_vmcircbuf_sysv_shm: shmdt (a)"); // Debug line added
>   }
> 
>   // first read-only guard page
>   if (shmat (shmid_guard, first_copy, SHM_RDONLY) == (void *) -1){
>     perror ("gr_vmcircbuf_sysv_shm: shmat (2)");
>     fprintf (stderr, "gr_vmcircbuf_sysv_shm: shmid_guard=%d, 
> first_copy=0x%x\n", shmid_guard, (unsigned int) first_copy);
>     shmctl (shmid_guard, IPC_RMID, 0);
>     shmctl (shmid1, IPC_RMID, 0);
>     throw std::runtime_error ("gr_vmcircbuf_sysv_shm");
>   }
> 
>   // first copy
>   if (shmat (shmid1, (char *) first_copy + pagesize, 0) == (void *) -1){
>     perror ("gr_vmcircbuf_sysv_shm: shmat (3)");
>     fprintf (stderr, "gr_vmcircbuf_sysv_shm: shmid1=%d, 
> first_copy+pagesize=0x%x\n", shmid1, (unsigned int) ((char *) first_copy + 
> pagesize));
>     shmctl (shmid_guard, IPC_RMID, 0);
>     shmctl (shmid1, IPC_RMID, 0);
>     shmdt (first_copy);
>     throw std::runtime_error ("gr_vmcircbuf_sysv_shm");
>   }
> 
> On an earlier test run where the shmat (2) line failed, this was the debug 
> output from the above code:
> 
> 6: Testing gr_vmcircbuf_sysv_shm_factory...
> 6: gr_vmcircbuf_sysv_shm: shmat (2): Invalid argument
> 6: gr_vmcircbuf_sysv_shm: shmid_guard=98304, first_copy=0x400e9000
> 
> Not sure how this will affect my system. Posting this more of an FYI.
> 
> I can add more details about the build if needed.
> 
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