Segmentaion fault after using operator new

Question

I have a C++ code built for ARM target using linaro toolchain built specifically from source for the ARM hardware target (with softfp, mtune=cortex-a9 etc...) At times, the code crashes with below trace. I had attached gdb to the running process Apparently it seems to crash few calls after a new operator from libstdc++.so.6 is invoked.

We at moment don't have exception handling code, so If new was failing and throwing exception i presumed it would have aborted/terminated with message like:

Program received signal SIGABRT, Aborted.

but instead it crashes with SIGSEGV.

Why is that so? What could be going wrong ?

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x45c6b460 (LWP 1182)]
0x402fad12 in malloc_consolidate () from /lib/libc.so.6
#0  0x402fad12 in malloc_consolidate () from /lib/libc.so.6
#1  0x402fc498 in _int_malloc () from /lib/libc.so.6
#2  0x402fe414 in malloc () from /lib/libc.so.6
#3  0x401f54d6 in operator new(unsigned int) () from /lib/libstdc++.so.6
#4  0x400f30d4 in MyMsg::operator=(MyPkt*) () from /usr/lib/libmy-ARMV7AL.so
#5  0x400f322c in MyMsg::reply() () from /usr/lib/libmy-ARMV7AL.so
#6  0x0005a6a0 in MyManager::SendMessage (this=0x7188c8)
    at MyManager.cpp:12973
#7  0x0004389c in My::Response (this=0x7188c8)
    MyManager.cpp:5972

Answer 1

It could be heap corruption (explaining why malloc terminates the process).

Use your regular tooling to detect undefined behaviour (such as bad memory accesses).

If it's exception handling gone awry (not too unusual in the presence of ABI stressors like cross-compilation), you might use nothrow version of operator new:

X* x = new (nothrow) X;

assert(x); // or otherwise handle with care

Answer 2

new throws an exception if there is not enough memory left. But there is no exception within the log. So I suppose there is enough memory. The more likely answer is that you have somehow corrupted the memory. You should check your memory accesses with valgrind

What bothers me more is the prototype of the = operator ; MyMsg::operator=(MyPkt*). Why taking a pointer and not a const reference on the object ? Or a least a const MyPkt const *