<div dir="ltr">Hi,<div><br></div><div>Thanks to both of you for helping me out with this!</div><div><br></div><div>When I backtrace on _Terminate: I get this:</div><div><br></div><div>Init -> rtems_task_create -> ... -> _Heap_Allocate -> ... ->_Heap_Protection_check_free_block -> _Heap_Protection_block_error ->_Heap_Protection_block_error_default -> _Terminate (the_source=RTEMS_FATAL_SOURCE_HEAP, the_error=2125180). So I will try to debug this trace.<br></div><div><br></div><div>Also, setting a watchpoint doesn't help:</div><div><br></div><div>Thread 1 hit Breakpoint 6, Init (argument=2107944) at /home/richi/quick-start/LatestStrong/src/rtems/c/src/../../testsuites/sptests/sp02/init.c:26<br>26 TEST_BEGIN();<br>(gdb) watch *(unsigned int)* 0x202ba8<br>Hardware watchpoint 13: *(unsigned int)* 0x202ba8<br>(gdb) c<br>Continuing.<br><br>Thread 1 hit Breakpoint 5, _Terminate (the_source=RTEMS_FATAL_SOURCE_HEAP, the_error=2125180) at /home/richi/quick-start/LatestStrong/src/rtems/c/src/../../cpukit/score/src/interr.c:38<br>38 _User_extensions_Fatal( the_source, the_error );<br></div><div><br></div><div> </div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Mar 3, 2021 at 10:20 PM Gedare Bloom <<a href="mailto:gedare@rtems.org">gedare@rtems.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">On Wed, Mar 3, 2021 at 9:49 AM Gedare Bloom <<a href="mailto:gedare@rtems.org" target="_blank">gedare@rtems.org</a>> wrote:<br>
><br>
> On Wed, Mar 3, 2021 at 9:28 AM Joel Sherrill <<a href="mailto:joel.sherrill@gmail.com" target="_blank">joel.sherrill@gmail.com</a>> wrote:<br>
> ><br>
> ><br>
> ><br>
> > On Wed, Mar 3, 2021 at 9:50 AM Gedare Bloom <<a href="mailto:gedare@rtems.org" target="_blank">gedare@rtems.org</a>> wrote:<br>
> >><br>
> >> On Wed, Mar 3, 2021 at 12:08 AM Richi Dubey <<a href="mailto:richidubey@gmail.com" target="_blank">richidubey@gmail.com</a>> wrote:<br>
> >> ><br>
> >> > What's the element written after the free? I set a watch at the exact block location, but it doesn't work:<br>
> >> ><br>
> >> > Hardware watchpoint 7: *0x202ba8<br>
> >> > (gdb) watch *0x206fec<br>
> >> > Hardware watchpoint 8: *0x206fec<br>
> >> That's just the first byte in the block. If you can figure out which<br>
> >> bytes/words in the block get accessed that would help you.<br>
> ><br>
> ><br>
> > What about watch *(unsigned int)* 0x202ba8?<br>
> ><br>
> > Won't that look at more bytes?<br>
><br>
> And this is just the first byte of the workspace area.<br>
><br>
4 bytes :)<br>
> ><br>
> > In case you do need to look at more bytes in the fence...<br>
> > breaking at _Terminate and doing a back trace will give<br>
> > you the exact line the error is raised from. You can then set a<br>
> > breakpoint at that on the next line and look at local variables.<br>
> > The corruption may be in the fence somewhere beyond the<br>
> > first 32-bits.<br>
> ><br>
In the case of heap corruption, the corruption is detected after it<br>
already happened. Narrowing down when/where the corruption happens is<br>
necessary. The next thing to do would be to examine the pattern that<br>
triggers the violation, and see where it got modified. This might<br>
provide a byte address to set a watch on.<br>
<br>
> > Sometimes it is easy to binary search for an issue like this<br>
> > on a simulator. But with a watchpoint, you should be able to<br>
> > determine the precise word which is corrupted in the fence<br>
> > and break on that write.<br>
> ><br>
> > --joel<br>
> >><br>
> >><br>
> >> > (gdb) c<br>
> >> > Continuing.<br>
> >> ><br>
> >> > Thread 1 hit Breakpoint 6, Init (argument=2107944) at /home/richi/quick-start/LatestStrong/src/rtems/c/src/../../testsuites/sptests/sp02/init.c:26<br>
> >> > 26 TEST_BEGIN();<br>
> >> > (gdb)<br>
> >> > Continuing.<br>
> >> ><br>
> >> > Thread 1 hit Breakpoint 5, _Terminate (the_source=RTEMS_FATAL_SOURCE_HEAP, the_error=2125180) at /home/richi/quick-start/LatestStrong/src/rtems/c/src/../../cpukit/score/src/interr.c:38<br>
> >> > 38 _User_extensions_Fatal( the_source, the_error );<br>
> >> > (gdb)<br>
> >> > Continuing.<br>
> >> ><br>
> >> > Thread 1 hit Breakpoint 4, bsp_reset () at /home/richi/quick-start/LatestStrong/src/rtems/c/src/lib/libbsp/arm/realview-pbx-a9/../../../../../../bsps/arm/realview-pbx-a9/start/bspreset.c:19<br>
> >> > 19 volatile uint32_t *sys_lock = (volatile uint32_t *) 0x10000020;<br>
> >> > (gdb)<br>
> >> ><br>
> >> > On Wed, Mar 3, 2021 at 12:31 PM Sebastian Huber <<a href="mailto:sebastian.huber@embedded-brains.de" target="_blank">sebastian.huber@embedded-brains.de</a>> wrote:<br>
> >> >><br>
> >> >> On 02/03/2021 05:44, Richi Dubey wrote:<br>
> >> >><br>
> >> >> ><br>
> >> >> > (gdb) p *(Heap_Error_context*)(0x00206d7c)<br>
> >> >> > $5 = {<br>
> >> >> > heap = 0x202ba8 <_Workspace_Area>,<br>
> >> >> > block = 0x206fec,<br>
> >> >> > reason = HEAP_ERROR_FREE_PATTERN<br>
> >> >> > }<br>
> >> >><br>
> >> >> If it is always the same address, then you can set a watch point to an<br>
> >> >> element which is written after the free to catch the function which<br>
> >> >> writes into this area.<br>
> >> >><br>
> >> >> --<br>
> >> >> embedded brains GmbH<br>
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</blockquote></div>