Potential memory leak in Objects/bytesobject.c

[RuiliF]

Bug report

cpython/Objects/bytesobject.c

Lines 429 to 443 in 206f05a

	p = PyOS_double_to_string(x, type, prec, dtoa_flags, NULL);
	if (p == NULL)
	return NULL;
	len = strlen(p);
	if (writer != NULL) {
	str = _PyBytesWriter_Prepare(writer, str, len);
	if (str == NULL)
	return NULL;
	memcpy(str, p, len);
	PyMem_Free(p);
	str += len;
	return str;
	}

At line 438, object p won't be freed if _PyBytesWriter_Prepare fails (returns NULL) and thus become a memory leak.

Linked PRs

• gh-101056: Fix memory leak in formatfloat() in bytesobject.c #101057
• [3.10] gh-101056: Fix memory leak in formatfloat() in bytesobject.c (GH-101057) #101076
• [3.11] gh-101056: Fix memory leak in formatfloat() in bytesobject.c (GH-101057) #101077

[sobolevn]

Good catch! @RuiliF thanks a lot!

How do you detect it? Do you use some kind of tooling? Or just by hand? :)

[RuiliF]

Good catch! @RuiliF thanks a lot!

How do you detect it? Do you use some kind of tooling? Or just by hand? :)

Thank you for the quick response! I found it just by hand. :)

[sobolevn]

If you have others to report - you are more than welcome! 👍

[sobolevn]

Done!