https://bugs.kde.org/show_bug.cgi?id=492549
Bug ID: 492549
Summary: std::string::find(char) breaks with massif
Classification: Developer tools
Product: valgrind
Version: 3.19.0
Platform: RedHat Enterprise Linux
OS: Linux
Status: REPORTED
Severity: normal
Priority: NOR
Component: massif
Assignee: n...@valgrind.org
Reporter: martin.lu...@ohb.de
Target Milestone: ---
SUMMARY
valgrind --tool=massif produces wrong behaviour in C++ std::string::find(char)
STEPS TO REPRODUCE
Create a file eg test.cpp with the following content:
#include <string>
#include <iostream>
int main()
{
std::string s = "haystack";
std::cout << s.find('x', 0) << std::endl;
std::cout << s.find("x", 0) << std::endl;
}
Compile it: g++ test.cpp
Run it as follows:
./a.out
valgrind ./a.out
valgrind --tool=massif ./a.out
OBSERVED RESULT
We expect std::string::npos aka the unsigned interpretation of -1, because the
character is not contained in the string.
But if massif is enabled, the character is suddenly reported as present:
~$ ./a.out
18446744073709551615
18446744073709551615
~$ valgrind -q ./a.out
18446744073709551615
18446744073709551615
~$ valgrind --tool=massif -q ./a.out
0
18446744073709551615
EXPECTED RESULT
~$ ./a.out
18446744073709551615
18446744073709551615
~$ valgrind -q ./a.out
18446744073709551615
18446744073709551615
~$ valgrind --tool=massif -q ./a.out
18446744073709551615
18446744073709551615
SOFTWARE/OS VERSIONS
OS: Oracle Linux 9
uname -a: Linux localhost.localdomain 5.15.0-101.103.2.1.el9uek.x86_64 #2 SMP
Tue May 2 01:10:45 PDT 2023 x86_64 x86_64 x86_64 GNU/Linux
g++: gcc version 11.3.1 20221121 (Red Hat 11.3.1-4.3.0.1) (GCC)
valgrind-3.19.0
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