https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108085
Bug ID: 108085
Summary: gcc trunk's ASAN at -O3 missed a stack-use-after-scope
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: sanitizer
Assignee: unassigned at gcc dot gnu.org
Reporter: shaohua.li at inf dot ethz.ch
CC: dodji at gcc dot gnu.org, dvyukov at gcc dot gnu.org,
jakub at gcc dot gnu.org, kcc at gcc dot gnu.org, marxin at
gcc dot gnu.org
Target Milestone: ---
For the following code, ASAN at -O3 failed to report the stack-use-after-scope,
other opt levels detected it successfully.
GCC-8 works fine.
Clang at all optimization levels reported it.
Compiler explorer: https://godbolt.org/z/jbsThYWa6
% cat a.c
int a;
void b() {
int c[1];
c;
}
int main() {
int d[1]={1};
int *e = d;
a = 0;
for (; a <= 5; ++a) {
int f[1]={};
e = f;
a || (b(), 1);
}
return *e;
}
%
% gcc-tk -O2 -fsanitize=address -g a.c && ./a.out
=================================================================
==780198==ERROR: AddressSanitizer: stack-use-after-scope on address
0x7f2307600030 at pc 0x0000004011c5 bp 0x7ffdd19ecd80 sp 0x7ffdd19ecd78
READ of size 4 at 0x7f2307600030 thread T0
#0 0x4011c4 in main /a.c:15
#1 0x7f2309f41082 in __libc_start_main
(/lib/x86_64-linux-gnu/libc.so.6+0x24082) (BuildId:
1878e6b475720c7c51969e69ab2d276fae6d1dee)
#2 0x40126d in _start (/a.out+0x40126d)
Address 0x7f2307600030 is located in stack of thread T0 at offset 48 in frame
#0 0x4010bf in main /a.c:6
This frame has 3 object(s):
[32, 36) 'd' (line 7)
[48, 52) 'f' (line 11) <== Memory access at offset 48 is inside this
variable
[64, 68) 'c' (line 3)
...
%
% gcc-tk -O3 -fsanitize=address -g a.c && ./a.out
%
