hi,
i just wrote two little applications, using libfusion for IPC.
they seem to run into an SIGSEGV under certain conditions.
i first start up my master application, followed by the client. the client
crashes every _first_ time it is started.
if i start it a second time against the still running master process, it works
just as it is supposed to.
first some code snipplets:
//MASTER//
/*the master allocates some memory*/
ret_err = fusion_shm_pool_create( state->dfb->fworld, "KitvPool", 0x500000,0,
&state->dfb->pool );
/* Create the Arena */
fusion_arena_enter (state->dfb->fworld,"kitv",initializeKitvArena,
initializeKitvArena,state,&state->dfb->arena,&ret_err);
<---->
/* Allocate some memory for the main process structure */
state->kitv_main=(kitv_main_process_t*)SHMALLOC(state->dfb->pool,
sizeof(kitv_main_process_t));
fusion_arena_add_shared_field (arena, "kitv_main", (void *)state->kitv_main );
<---->
(this is called via rpc from the client)
kitv_screen_process_t *new_screen_process;
/* first allocate the new screen_process structure */
new_screen_process =(kitv_screen_process_t*)SHMALLOC(state->dfb->pool,
sizeof(kitv_screen_process_t));
/* then publish the field */
fusion_arena_add_shared_field (state->dfb->arena, field_name, (void
*)new_screen_process );
// sleep (1);
//CLIENT//
/* first join the kitv arena */
fusion_arena_enter(dfb->fworld, "kitv",fusionJoin,fusionJoin,NULL,
&dfb->arena, &ret_err );
/* now get the kitv_main structure */
fusion_arena_get_shared_field(dfb->arena, "kitv_main", (void **)&kitv_main);
(rpc init : see master )
/* grab the new kitv_screen_process field, it is named after our pid */
dr = fusion_arena_get_shared_field(dfb->arena, screen_name, (void
**)&kitv_screen);
if ( dr != DFB_OK ) {
printf ("init: failed get shared field %sn",screen_name);
exit ( -1 );
}
printf ("field %xn",kitv_screen);
printf (" found %dn",kitv_screen->id);
>>SIGSEGV<< occurs here
the debug/trace log 1st execution :
process with pid 20901 is the client
(-) [Main Thread 12.559] (20901) Fusion/Main: -> done. (0x805f2b0)
(-) [Main Thread 12.559] (20901) Fusion/Arena: entering arena 'kitv'
(joining)
(-) [Fusion Dispatch 12.559] (20900) Fusion/SHMPool:
fusion_shm_pool_allocate( 0x200040b0, 140, unclear, 0xb5deee98 )
(-) [Fusion Dispatch 12.559] (20900) Fusion/SHMHeap: _fusion_shmalloc(
0x28614000, 140 )
(-) [Fusion Dispatch 12.559] (20900) Fusion/SHMHeap:
_fusion_shmalloc( 0x28614000, 4096 )
(-) [Fusion Dispatch 12.559] (20900) Fusion/SHMHeap: morecore(
0x28614000, 4096 )
(-) [Fusion Dispatch 12.559] (20900) Fusion/SHMHeap: align(
0x28614000, 4096 )
(-) [Fusion Dispatch 12.559] (20900) Fusion/SHMHeap:
__shmalloc_brk( 0x28614000, 4096 )
(-) [Fusion Dispatch 12.559] (20900) Fusion/SHMHeap:
-> remapped (28672 -> 32768)
(-) [Fusion Dispatch 12.559] (20900) Fusion/SHMPool:
fusion_shm_pool_allocate( 0x2000406c, 116, clear, 0xb5deee98 )
(-) [Fusion Dispatch 12.559] (20900) Fusion/SHMHeap: _fusion_shmalloc(
0x28513000, 116 )
(-) [Fusion Dispatch 12.560] (20900) Fusion/SHMPool:
fusion_shm_pool_allocate( 0x2000406c, 102, unclear, 0xb5deee98 )
(-) [Fusion Dispatch 12.560] (20900) Fusion/SHMHeap: _fusion_shmalloc(
0x28513000, 102 )
(-) [Fusion Dispatch 12.560] (20900) Fusion/SHMPool:
fusion_shm_pool_allocate( 0x200040b0, 80, unclear, 0xb5deee28 )
(-) [Fusion Dispatch 12.560] (20900) Fusion/SHMHeap: _fusion_shmalloc(
0x28614000, 80 )
(!) [20901: 12.560] --> Caught signal 11 (at 0x2861b004, invalid address) <--
the debug/trace log 2nd execution :
now 20908 is the client
(-) [Main Thread 16.084] (20908) Fusion/Arena: entering arena 'kitv'
(joining)
(-) [Fusion Dispatch 16.084] (20900) Fusion/SHMPool:
fusion_shm_pool_allocate( 0x200040b0, 140, unclear, 0xb5deee98 )
(-) [Fusion Dispatch 16.084] (20900) Fusion/SHMHeap: _fusion_shmalloc(
0x28614000, 140 )
(-) [Fusion Dispatch 16.084] (20900) Fusion/SHMPool:
fusion_shm_pool_allocate( 0x2000406c, 116, clear, 0xb5deee98 )
(-) [Fusion Dispatch 16.084] (20900) Fusion/SHMHeap: _fusion_shmalloc(
0x28513000, 116 )
(-) [Fusion Dispatch 16.084] (20900) Fusion/SHMPool:
fusion_shm_pool_allocate( 0x2000406c, 102, unclear, 0xb5deee98 )
(-) [Fusion Dispatch 16.084] (20900) Fusion/SHMHeap: _fusion_shmalloc(
0x28513000, 102 )
(-) [Screen Update 16.084] (20899) SDL/Updates: -> unlocking dfb
surface...
(-) [Screen Update 16.084] (20899) Core/Surface:
dfb_surface_unlock( 0x20016460, front )
(-) [Screen Update 16.084] (20899) Core/Surface: ->
system/video count: 1/0 before
(-) [Screen Update 16.084] (20899) Core/Surface: ->
system/video count: 0/0 after
(-) [Screen Update 16.084] (20899) SDL/Updates: -> unlocking sdl
surface...
(-) [Screen Update 16.084] (20899) SDL/Updates: -> calling
SDL_UpdateRect()...
(-) [Fusion Dispatch 16.086] (20897) Fusion/SHMPool:
fusion_shm_pool_deallocate( 0x200000b0, 0x20115c80 )
(-) [Fusion Dispatch 16.086] (20897) Fusion/SHMHeap: _fusion_shfree(
0x20111000, 0x20115c80 )
(-) [Screen Update 16.087] (20899) SDL/Updates: -> unlocking sdl
lock...
(-) [Screen Update 16.087] (20899) SDL/Updates: -> done.
(*) Direct/Interface: Loaded 'JPEG' implementation of 'IDirectFBImageProvider'.
(-) [Main Thread 16.087] (20908) Core/Layers:
dfb_layer_get_active_context (SDL Primary Layer)
>>works fine now<<
if i enable the sleep (1); in the master code above everything works fine.
to me it looks like the shared memory is inconsistent while remapping. it might
need some locking.
for a start i tried locking the arenas_lock in the FusionSharedWorld from
fusion_get_shared_field and fusion_shm_pool_allocate . it doesn't really help
though. it's working from time to time now, but propably just because it's
slowing stuff down a lot.
i keep on trying, but my knowledge of the whole fusion stuff is pretty limited.
apart from this bug(?, or is it just me being to stupid, allocating the pool
wrong or whatever) the whole directfb library is _very_ enjoyable and
straightforward to use. thanks a lot!
ben
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