The error content of `AddressSanitizerComparisonOfMemoryTools` page

[zhangm365]

1. Valgrind can detect the UAR memory error.

// g++ -g mem_UAR.cc
 #include<iostream>
 #include<new>
 
 int *ptr;
 __attribute__((noinline))
 void FunctionThatEscapesLocalObject() {
   int local[100];
   ptr = &local[0];
 }
 
 int main(int argc, char **argv) {
   FunctionThatEscapesLocalObject();
   printf("argc = %d\n", argc);
   return ptr[argc];
 }

valgrind --tool=memcheck --leak-check=full --show-leak-kinds=all --gen-suppressions=all --time-stamp=yes --error-markers=VALGRINDERROR-BEGIN,VALGRINDERROR-END --log-file=$HOME/pg-valgrind/log/%p.log --trace-children=yes     ~/test/a.out 2>&1 | tee $HOME/pg-valgrind/postmaster.log

The log is as follows:

==00:00:00:01.098 1491957== VALGRINDERROR-BEGIN
==00:00:00:01.098 1491957== Invalid read of size 4
==00:00:00:01.098 1491957==    at 0x1091F7: main (mem_UAR.cc:13)
==00:00:00:01.098 1491957==  Address 0x1ffeffff34 is on thread 1's stack
==00:00:00:01.098 1491957==  428 bytes below stack pointer
==00:00:00:01.098 1491957== 
==00:00:00:01.098 1491957== VALGRINDERROR-END

So, the Valgrind can detect the UAF error.

2. Valgrind can detect the StackOOB memory error.

 int main(int argc, char **argv) {
   int stack_array[100] = {0};
 
   return stack_array[argc + 100]; // BOOM
 }

Output file:

==00:00:00:01.257 1519192== VALGRINDERROR-BEGIN
==00:00:00:01.257 1519192== Syscall param exit_group(status) contains uninitialised byte(s)
==00:00:00:01.257 1519192==    at 0x4B81C31: _Exit (_exit.c:30)
==00:00:00:01.257 1519192==    by 0x4ADC551: __run_exit_handlers (exit.c:136)
==00:00:00:01.257 1519192==    by 0x4ADC60F: exit (exit.c:143)
==00:00:00:01.257 1519192==    by 0x4AC0D96: (below main) (libc_start_call_main.h:74)
==00:00:00:01.257 1519192==  Uninitialised value was created by a stack allocation
==00:00:00:01.257 1519192==    at 0x109189: main (mem_StackOOB.cc:4)
==00:00:00:01.257 1519192== 
==00:00:00:01.257 1519192== VALGRINDERROR-END

Please fix it in the summary table.
zhangm365.