[Starpu-devel] Deadlocks

[Sylvain HENRY <sylvain.henry@inria.fr>]

 Hi,

My program deadlocks with the following stack trace:

^C
Program received signal SIGINT, Interrupt.
__lll_lock_wait () at 
../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:136
136     ../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S: No such 
file or directory.
        in ../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S
(gdb) bt
#0  __lll_lock_wait () at 
../nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.S:136
#1  0x00007ffff566e0e9 in _L_lock_953 () from /lib/libpthread.so.0
#2  0x00007ffff566df0b in __pthread_mutex_lock (mutex=0x7fffe84f3248) at 
pthread_mutex_lock.c:61
#3  0x00007ffff6c8a289 in starpu_task_declare_deps_array (task=<value 
optimized out>, ndeps=1, task_array=<value optimized out>) at 
../../src/core/dependencies/task_deps.c:84
#4  0x00007ffff6c88dea in _starpu_detect_implicit_data_deps_with_handle 
(pre_sync_task=0x7fffe84f7fd0, post_sync_task=0x7fffe84f7fd0, 
handle=0xc77ce0, mode=3) at 
../../src/core/dependencies/implicit_data_deps.c:61
#5  0x00007ffff6c88fb9 in _starpu_detect_implicit_data_deps 
(task=0x7fffe84f7fd0) at 
../../src/core/dependencies/implicit_data_deps.c:182
#6  0x00007ffff6c86035 in starpu_task_submit (task=0x7fffe84f7fd0) at 
../../src/core/task.c:214
#7  0x00007ffff7bd901d in commandQueueEnqueueBarrierEvent () from 
/home/shenry/.usr/lib/libsocl.so
#8  0x0000000000417d59 in viennacl::ocl::kernel::start1D(unsigned int 
const&, unsigned int const&) ()
#9  0x000000000041da5e in viennacl::linalg::inner_prod_impl<float, 1u> ()
#10 0x000000000042a673 in viennacl::vector<float, 1u> 
viennacl::linalg::solve<viennacl::compressed_matrix<float, 4u>, 
viennacl::vector<float, 1u> >(viennacl::compressed_matrix<float, 4u> 
const&, viennacl::vector<float, 1u> const&, viennacl::linalg::cg_tag 
const&) ()
#11 0x000000000045d0b9 in int run_benchmark<float>() ()
#12 0x000000000041e496 in main ()

If I disable implicit data dependency flag on my data, I don't have this 
problem. Now the problem is unfinishing task:

^C
Program received signal SIGINT, Interrupt.
pthread_cond_wait@@GLIBC_2.3.2 () at 
../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:162
162     ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S: No 
such file or directory.
        in ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S
(gdb) bt
#0  pthread_cond_wait@@GLIBC_2.3.2 () at 
../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:162
#1  0x00007ffff6c81d53 in _starpu_wait_job (j=0x7fffd4008920) at 
../../src/core/jobs.c:109
#2  0x00007ffff6c82a1c in starpu_task_submit (task=0x7fffd40087c0) at 
../../src/core/task.c:247
#3  0x00007ffff7bd865b in commandQueueEnqueueBarrierEvent 
(cq=0x7fffe80b0250, ev=0x7fffd4008790) at 
../lib/helpers_commandqueue.c.inc:62
#4  0x00007ffff7bd86a1 in commandQueueEnqueueEvent (cq=0x7fffe80b0250, 
ev=0x7fffd4008790) at ../lib/helpers_commandqueue.c.inc:72
#5  0x00007ffff7bda9a2 in soclEnqueueReadBuffer (cq=0x7fffe80b0250, 
buffer=0x7fffebb970e0, blocking=1, offset=0, cb=4, ptr=0x7fffffffd52c, 
num_events=0, events=0x0, event=0x0) at 
../lib/cl_enqueuereadbuffer.c.inc:125
#6  0x000000000042a897 in viennacl::vector<float, 1u> 
viennacl::linalg::solve<viennacl::compressed_matrix<float, 4u>, 
viennacl::vector<float, 1u> >(viennacl::compressed_matrix<float, 4u> 
const&, viennacl::vector<float, 1u> const&, viennacl::linalg::cg_tag 
const&) ()
#7  0x000000000045d0b9 in int run_benchmark<float>() ()
#8  0x000000000041e496 in main ()

How can I debug this to understand why my task never terminates?

Cheers
Sylvain