Skip to content

fix #13960: False negative: no error when freeing struct member twice (regression) #7626

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 2 commits into from
Jun 26, 2025
Merged

fix #13960: False negative: no error when freeing struct member twice (regression) #7626

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
1076eff
add test
ludviggunne Jun 23, 2025
f87c14c
fix #13960
ludviggunne Jun 25, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
12 changes: 6 additions & 6 deletions lib/checkleakautovar.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -413,8 +413,6 @@ bool CheckLeakAutoVar::checkScope(const Token * const startToken,
// assignment..
if (const Token* const tokAssignOp = isInit ? varTok : isAssignment(varTok)) {

if (Token::simpleMatch(tokAssignOp->astOperand1(), "."))
continue;
// taking address of another variable..
if (Token::Match(tokAssignOp, "= %var% +|;|?|%comp%")) {
if (varTok->tokAt(2)->varId() != varTok->varId()) {
Expand Down Expand Up @@ -730,8 +728,7 @@ bool CheckLeakAutoVar::checkScope(const Token * const startToken,
VarInfo::AllocInfo allocation(af ? af->groupId : 0, VarInfo::DEALLOC, ftok);
if (allocation.type == 0)
allocation.status = VarInfo::NOALLOC;
if (Token::simpleMatch(ftok->astParent(), "(") && Token::simpleMatch(ftok->astParent()->astOperand2(), "."))
continue;

functionCall(ftok, openingPar, varInfo, allocation, af);

tok = ftok->linkAt(1);
Expand Down Expand Up @@ -886,7 +883,7 @@ const Token * CheckLeakAutoVar::checkTokenInsideExpression(const Token * const t
while (rhs->isCast()) {
rhs = rhs->astOperand2() ? rhs->astOperand2() : rhs->astOperand1();
}
if (rhs->varId() == tok->varId() && isAssignment) {
if ((rhs->str() == "." || rhs->varId() == tok->varId()) && isAssignment) {
// simple assignment
varInfo.erase(tok->varId());
} else if (rhs->astParent() && rhs->str() == "(" && !mSettings->library.returnValue(rhs->astOperand1()).empty()) {
Expand Down Expand Up @@ -1024,7 +1021,10 @@ void CheckLeakAutoVar::functionCall(const Token *tokName, const Token *tokOpenin
arg = arg->astOperand2() ? arg->astOperand2() : arg->astOperand1();
const Token * const argTypeStartTok = arg;

while (Token::Match(arg, "%name% :: %name%"))
if (Token::simpleMatch(arg, "."))
arg = arg->next();

while (Token::Match(arg, "%name% .|:: %name%"))
arg = arg->tokAt(2);

if ((Token::Match(arg, "%var% [-,)] !!.") && !(arg->variable() && arg->variable()->isArray())) ||
Expand Down
13 changes: 13 additions & 0 deletions test/testleakautovar.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -109,6 +109,7 @@ class TestLeakAutoVar : public TestFixture {
TEST_CASE(doublefree16);
TEST_CASE(doublefree17); // #8109: delete with comma operator
TEST_CASE(doublefree18);
TEST_CASE(doublefree19); // #13960

// exit
TEST_CASE(exit1);
Expand Down Expand Up @@ -1814,6 +1815,18 @@ class TestLeakAutoVar : public TestFixture {
ASSERT_EQUALS("", errout_str());
}

void doublefree19() {
check("struct S {\n"
" void *x;\n"
"};\n"
"void f(struct S *p)\n"
"{\n"
" free(p->x);\n"
" free(p->x);\n"
"}\n");
ASSERT_EQUALS("[test.c:6:3] -> [test.c:7:3]: (error) Memory pointed to by 'x' is freed twice. [doubleFree]\n", errout_str());
}

void exit1() {
check("void f() {\n"
" char *p = malloc(10);\n"
Expand Down
Loading