[Valgrind-users] Fwd: No "by" message in memcheck output

[Michael O. <mto...@gm...>]

---------- Forwarded message ---------
From: Michael Ortiz <mto...@gm...>
Date: Tue, Jul 13, 2021 at 3:52 PM
Subject: Re: [Valgrind-users] No "by" message in memcheck output
To: Paul FLOYD <pj...@wa...>


I found a resolution to this issue here:
http://arago-project.org/pipermail/meta-arago/2015-August/006016.html

The resolution is to include the debug symbols
for vgpreload_memcheck-arm-linux.so. After doing so the callstack is
reported in the memcheck output:

==8828== Thread 1:
==8828== 5 bytes in 1 blocks are definitely lost in loss record 1 of 1
==8828==    at 0x4845BD4: malloc (vg_replace_malloc.c:309)
==8828==    by 0x73D6B: main (example.cpp:158)

Cheers,
Mike


On Tue, Jul 13, 2021 at 2:01 PM Michael Ortiz <mto...@gm...>
wrote:

> Thanks for the reply,
>
> I set the malloc breakpoint in gdb per your suggestion and the
> callstack shows that the offending call is in main:
>
> Breakpoint 15, 0x00072760 in malloc@plt ()
> (gdb) where
> #0  0x00072760 in malloc@plt ()
> #1  0x00073d6c in main (argc=<optimized out>, argv=<optimized out>) at
> /home/mortiz/test/example.cpp:158
>
> As you noted, I am running on armv7l. I wonder if the callstack output is
> not supported in the "HEAP SUMMARY" for this architecture.
>
> For reference, I am using valgrind provided by yocto zeus (3.0.3).
>
> Mike
>
> On Tue, Jul 13, 2021 at 12:53 AM Paul FLOYD <pj...@wa...> wrote:
>
>>
>> > De : "Michael Ortiz"
>> > Objet : [Valgrind-users] No "by" message in memcheck output
>>
>>
>> Hi
>>
>> It's possible that the call to malloc is before the start of main
>> (either from your libc or for the initialization of some static or global
>> object).
>> I know next to nothing about the ARM ABI, but on amd64 Linux
>> the callstack in this case contains things like
>>
>> ==1441== 4 bytes in 1 blocks are still reachable in loss record 1 of 2
>> ==1441== at 0x402DF66: operator new(unsigned long)
>> (vg_replace_malloc.c:417)
>> ==1441== by 0x401187: __static_initialization_and_destruction_0(int, int)
>> (source.cpp:1)
>> ==1441== by 0x4011A4: _GLOBAL__sub_I_pi (l.cpp:3)
>> ==1441== by 0x4011FC: __libc_csu_init (in /home/user/exe)
>> ==1441== by 0x4D48364: (below main) (in /usr/lib64/libc-2.17.so)
>>
>> Can you run your app under gdb, but a break on malloc and then run.
>> You should be able to see the callstack and then be able to tell if
>> Valgrind is telling you the right thing or not.
>>
>> A+
>> Paul
>>
>>
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>