Heap allocation for libbsd overwrites IMFS

[Sebastian Huber]

On 23/06/2021 10:32, Jan.Sommer at dlr.de wrote:
> One of our applications for the Zedboard fails with fatal error after the setup of the network stack in libbsd.
> So far I traced it down to the point that the memory allocation for libbsd overwrites parts of the IMFS of rtems.
> When opening device files later this will lead to the crash.
> The backtrace looks like this for the bad allocation looks like this:
> _Heap_Block_split	../../../../../c/src/../../cpukit/score/src/heap.c:313	0x10dd58	
> _Heap_Block_allocate_from_begin	../../../../../c/src/../../cpukit/score/src/heap.c:378	0x10dfd6	
> _Heap_Block_allocate	../../../../../c/src/../../cpukit/score/src/heap.c:465	0x10dfd6	
> _Heap_Allocate_aligned_with_boundary	../../../../../c/src/../../cpukit/score/src/heapallocate.c:265	0x10e19c	
> rtems_heap_allocate_aligned_with_boundary	../../../../../c/src/../../cpukit/libcsupport/src/malloc_deferred.c:92	0x10962e	
> malloc	../../../../../c/src/../../cpukit/libcsupport/src/malloc.c:39	0x10950e	
> _bsd_malloc	../../rtemsbsd/rtems/rtems-kernel-malloc.c:80	0x170048	
> [more libbsd]
> ifconfig	../../freebsd/sbin/ifconfig/ifconfig.c:1024	0x1724fa
> 

You probably have a general memory corruption issue. As a first step I 
would enable RTEMS_DEBUG = True to enable the heap protection. This 
could help to debug the issue.

> With 1 GiB of RAM, available memory shouldn't be a problem.
> At the moment we have configured the system with CONFIGURE_UNLIMITED_OBJECTS and CONFIGURE_UNIFIED_WORK_AREAS.

This is fine.

> Maybe that is not right in this case. Are there any suggestions how to better configure the system?
> I found CONFIGURE_MEMORY_OVERHEAD in the docs, but I am not so sure how to use it or if it would help.

No, it would not help.

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