Hey Jeff

I seem to recall seeing the identical problem reported on the user list not long ago...or may have been the devel list. Anyway, it was during btl_sm_add_procs, and the code was segv'ing.

I don't have the archives handy here, but perhaps you might search them and see if there is a common theme here. IIRC, some of Eugene's fixes impacted this problem.

Ralph


On Mar 10, 2009, at 7:49 PM, Jeff Squyres wrote:

On Mar 10, 2009, at 9:13 PM, Jeff Squyres (jsquyres) wrote:

Doh -- I'm seeing intermittent sm btl failures on Cisco 1.3.1 MTT. :-
(  I can't reproduce them manually, but they seem to only happen in a
very small fraction of overall MTT runs.  I'm seeing at least 3
classes of errors:

1. btl_sm_add_procs.c:529 which is this:

       if(mca_btl_sm_component.fifo[j][my_smp_rank].head_lock !=
NULL) {

j = 3, my_smp_rank = 1.  mca_btl_sm_component.fifo[j][my_smp_rank]
appears to have a valid value in it (i.e., .fifo[3][0] = x, .fifo[3]
[1] = x+offset, .fifo[3][2] = x+2*offset, .fifo[3][3] = x+3*offset.
But gdb says:

(gdb) print mca_btl_sm_component.fifo[j][my_smp_rank]
Cannot access memory at address 0x2a96b73050



Bah -- this is a red herring; this memory is in the shared memory segment, and that memory is not saved in the corefile. So of course gdb can't access it (I just did a short controlled test and proved this to myself).

But I don't understand why I would have a bunch of tests that all segv at btl_sm_add_procs.c:529. :-(

--
Jeff Squyres
Cisco Systems

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