Error: use-after-poison

Address Sanitizer Error: Use of poisoned memory

A developer can manually poison memory to customize debugging.

Example

// example1.cpp
// use-after-poison error
#include <stdlib.h>

extern "C" void __asan_poison_memory_region(void *, size_t);

int main(int argc, char **argv) {
    char *x = new char[16];
    x[10] = 0;
    __asan_poison_memory_region(x, 16);

    int res = x[argc * 10];              // Boom!
 
    delete [] x;
    return res;
}

To build and test this example, run these commands in a Visual Studio 2019 version 16.9 or later developer command prompt:

cl example1.cpp /fsanitize=address /Zi
devenv /debugexe example1.exe

Resulting error

See also

AddressSanitizer overview
AddressSanitizer known issues
AddressSanitizer build and language reference
AddressSanitizer runtime reference
AddressSanitizer shadow bytes
AddressSanitizer cloud or distributed testing
AddressSanitizer debugger integration
AddressSanitizer error examples