https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106473
Bug ID: 106473
Summary: -Wanalyzer-malloc-leak false positive regression when
returning heap-allocation through nested pointers
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: analyzer
Assignee: dmalcolm at gcc dot gnu.org
Reporter: raimue at codingfarm dot de
Target Milestone: ---
Source:
void foo(char **args[], int *argc) {
*argc = 1;
(*args)[0] = __builtin_malloc(42);
}
Compiler output:
$ gcc-12 -Wall -fanalyzer -c -o foo.o foo.c
foo.c: In function 'foo':
foo.c:4:1: warning: leak of '<unknown>' [CWE-401] [-Wanalyzer-malloc-leak]
4 | }
| ^
'foo': events 1-2
|
| 3 | (*args)[0] = __builtin_malloc(42);
| | ^~~~~~~~~~~~~~~~~~~~
| | |
| | (1) allocated here
| 4 | }
| | ~
| | |
| | (2) '<unknown>' leaks here; was allocated at (1)
|
Notes:
This is only reported with the write to argc happening first, which should be
considered completely unrelated to args. Reordering the two statements resolves
the analyzer report.
Tested versions:
gcc 10.3: FAIL
gcc 11.2: OK
gcc 12.0: FAIL
I therefore consider this a regression as it was not reported by gcc 11.
Compiler Explorer link:
https://gcc.godbolt.org/z/zGanPa3fs
