Hi!
On 25/03/2019 17:14, Florian Weimer wrote:
* Andrew Haley:
On 3/25/19 2:01 PM, Florian Weimer wrote:
* Xi Ruoyao:
On 2019-03-25 13:06 +0000, Jonny Grant wrote:
I built & ran with the Sanitizer, it seems it's also stack overflow
within the operator new()
I had thoughts GCC would generate code that monitored the stack size and
aborted with a clear message when the stack size was exceeded. Looked
online, and it doesn't seem to be the case.
Impossible. We can't distinguish "stack overflow" with other segmentation
faults.
I think “impossible” is too strong.
It is. We do it with stack banging and a few guard pages in the HotSpot JVM.
The problem is that recovering well enough to throw an exception requires
some quite hairy non-portable code.
Of course it's going to be non-portable. Ideally, this would be
handled out-of-process: the shell registers itself with the system
coredump handler, and the handler analyzes the crash and provides
information back to the shell for display.
It's quite difficult to get there, but it's certainly not impossible.
We really should have lightweight tracebacks for aborts and the like
in C/C++ code. Right now, every moderately large piece of software
tries to write their robust in-process crash handler, with varying
results.
.
Could GCC add a simple crash handler? maybe -fcrash-handler
C++ exceptions show a few clues when there is a crash, which is helpful, eg:
// g++-8 -Wall -o cpp cpp.cpp
#include <vector>
int main()
{
std::vector<int> v;
return v.at(0);
}
$ ./cpp
terminate called after throwing an instance of 'std::out_of_range'
what(): vector::_M_range_check: __n (which is 0) >= this->size()
(which is 0)
Aborted
Jonny
