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. For example
int foo() {volatile char p[10000000]; p[0] = 1;}
and
int foo() {
volatile char a;
(&a)[-9999999] = 1;
}
may be compiled to exactly same machine code. Now which one is a stack
overflow?
> AddressSanitizer:DEADLYSIGNAL
> =================================================================
> ==16598==ERROR: AddressSanitizer: stack-overflow on address
> 0x7ffe4b0e7fc0 (pc 0x7f85c609293a bp 0x7ffe4b0e88d0 sp 0x7ffe4b0e7fb0 T0)
> #0 0x7f85c6092939 (/usr/lib/x86_64-linux-gnu/libasan.so.5+0x28939)
> #1 0x7f85c6091217 (/usr/lib/x86_64-linux-gnu/libasan.so.5+0x27217)
> #2 0x7f85c615974e in operator new(unsigned long)
> (/usr/lib/x86_64-linux-gnu/libasan.so.5+0xef74e)
> #3 0x563e23701a4a in void std::__cxx11::basic_string<char,
> std::char_traits<char>, std::allocator<char> >::_M_construct<char
> const*>(char const*, char const*, std::forward_iterator_tag)
> /usr/include/c++/8/bits/basic_string.tcc:219
> #4 0x563e23947131 in void std::__cxx11::basic_string<char,
> std::char_traits<char>, std::allocator<char> >::_M_construct_aux<char
> const*>(char const*, char const*, std::__false_type)
> /usr/include/c++/8/bits/basic_string.h:236
> #5 0x563e23947131 in void std::__cxx11::basic_string<char,
> std::char_traits<char>, std::allocator<char> >::_M_construct<char
> const*>(char const*, char const*) /usr/include/c++/8/bits/basic_string.h:255
> #6 0x563e23947131 in std::__cxx11::basic_string<char,
> std::char_traits<char>, std::allocator<char> >::basic_string(char
> const*, std::allocator<char> const&)
> /usr/include/c++/8/bits/basic_string.h:516
If you consume too much stack, stack overflow may happens in any functions. For
example:
int x()
{
int a[100];
malloc(1);
return x();
}
int main()
{
return x();
}
> Sanitizer says the same. There isn't really anything that can be done
> when stack is exceeded! There isn't a StackOverflowException
This is gcc-help, not java-help or python-help. But actually you can do
something here:
0. Do not consume so much stack. Throw large things into the heap.
1. Set a signal handler for SIGSEGV. And you will need sigaltstack so the
signal handler can run in an alternative stack.
2. Use ulimit -s or setrlimit to increase stack limit, if you really need more
stack.
3. Use -fsplit-stack to automatically "increase" stack size when it overflows,
if you really need this feature.
If you don't like all of these suggestions, go to use Java.
--
Xi Ruoyao <xry111@xxxxxxxxxxxxxxxx>
School of Aerospace Science and Technology, Xidian University
