1 // Test that out-of-scope local variables are ignored by LSan.
2
3 // LSan-in-ASan fails at -O0 on aarch64, because the stack use-after-return
4 // instrumentation stashes the argument to `PutPointerOnStaleStack` on the stack
5 // in order to conditionally call __asan_stack_malloc. This subverts our
6 // expectations for this test, where we assume the pointer is never stashed
7 // except at the bottom of the dead frame. Building at -O1 or greater solves
8 // this problem, because the compiler is smart enough to stash the argument in a
9 // callee-saved register for rematerialization instead.
10 // RUN: %clangxx_lsan -O1 %s -o %t
11
12 // RUN: %env_lsan_opts="report_objects=1:use_registers=0:use_stacks=1" not %run %t 2>&1 | FileCheck %s
13 // RUN: %env_lsan_opts="report_objects=1:use_registers=0:use_stacks=1:exitcode=0" %run %t 2>&1 | FileCheck --check-prefix=CHECK-sanity %s
14 //
15 // x86 passes parameters through stack that may lead to false negatives
16 // The same applies to s390x register save areas.
17 // UNSUPPORTED: i686,target={{(x86|powerpc64|arm|s390x).*}}
18
19 #include <stdio.h>
20 #include <stdlib.h>
21 #include "sanitizer_common/print_address.h"
22
23 void **pp;
24
25 // Put pointer far enough on the stack that LSan has space to run in without
26 // overwriting it.
27 // Hopefully the argument p will be passed on a register, saving us from false
28 // negatives.
29 __attribute__((noinline))
PutPointerOnStaleStack(void * p)30 void *PutPointerOnStaleStack(void *p) {
31 void *locals[2048];
32 locals[0] = p;
33 pp = &locals[0];
34 print_address("Test alloc: ", 1, locals[0]);
35 return 0;
36 }
37
main()38 int main() {
39 PutPointerOnStaleStack(malloc(1337));
40 return 0;
41 }
42
43 // This must run after LSan, to ensure LSan didn't overwrite the pointer before
44 // it had a chance to see it. If LSan is invoked with atexit(), this works.
45 // Otherwise, we need a different method.
46 __attribute__((destructor))
47 __attribute__((no_sanitize_address))
48 __attribute__((no_sanitize("hwaddress")))
ConfirmPointerHasSurvived()49 void ConfirmPointerHasSurvived() {
50 print_address("Value after LSan: ", 1, *pp);
51 }
52 // CHECK: Test alloc: [[ADDR:0x[0-9,a-f]+]]
53 // CHECK-sanity: Test alloc: [[ADDR:0x[0-9,a-f]+]]
54 // CHECK: LeakSanitizer: detected memory leaks
55 // CHECK: [[ADDR]] (1337 bytes)
56 // CHECK: SUMMARY: {{.*}}Sanitizer:
57 // CHECK-sanity: Value after LSan: [[ADDR]]
58