https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108510
Bug ID: 108510
Summary: ASAN missed a stack-use-after-scope at -O1
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, GCC's ASAN at -O1 missed the stack-use-after-scope,
while other opt levels detected it.
I checked the assembly code, -O1 didn't optimize away the buggy code.
Compiler explorer: https://godbolt.org/z/jWPG8hMWY
% cat a.c
short a;
char b;
short *c = &a, *d;
long e;
int main() {
long *f = &e;
{
int g=0;
d = &g;
}
*d << (b = ((*f)--, c || *d));
}
%
% gcc-tk -fsanitize=address -g -O1 a.c && ./a.out
%
% gcc-tk -fsanitize=address -g -O2 a.c && ./a.out
=================================================================
==1==ERROR: AddressSanitizer: stack-use-after-scope on address 0x7f0150b00020
at pc 0x0000004011a4 bp 0x7ffff43bc150 sp 0x7ffff43bc148
READ of size 2 at 0x7f0150b00020 thread T0
#0 0x4011a3 in main /a.c:11
#1 0x7f01534e6082 in __libc_start_main
(/lib/x86_64-linux-gnu/libc.so.6+0x24082) (BuildId:
1878e6b475720c7c51969e69ab2d276fae6d1dee)
#2 0x40123d in _start (/app/output.s+0x40123d) (BuildId:
2f09fd97ce9e5ec29ed33980daf91dfdd4bb3ebc)
Address 0x7f0150b00020 is located in stack of thread T0 at offset 32 in frame
#0 0x4010bf in main /a.c:5
...
%
