https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109968
Bug ID: 109968
Summary: False Warning stringop-overread when -O2 and
-fsanitize=address used
Product: gcc
Version: 13.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: davekelly13 at gmail dot com
Target Milestone: ---
Created attachment 55157
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=55157&action=edit
Preprocessed source
gcc-13 -O2 -fsanitize=address --save-temps x.c -S
x.c: In function ‘f’:
x.c:17:15: warning: ‘write’ reading 6 bytes from a region of size 4
[-Wstringop-overread]
17 | err = write( 1, (const void *)&(s->s2), 6);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
x.c:5:21: note: source object ‘b’ of size 4
5 | int b;
| ^
In file included from x.c:1:
/usr/include/unistd.h:378:16: note: in a call to function ‘write’ declared with
attribute ‘access (read_only, 2, 3)’
378 | extern ssize_t write (int __fd, const void *__buf, size_t __n) __wur
| ^~~~~
Preprocessed source attached.
Removing the "if ( s->s2.b == 1 ) return 0;" resolves the issue.
gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/12/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none:amdgcn-amdhsa
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu
12.2.0-17ubuntu1' --with-bugurl=file:///usr/share/doc/gcc-12/README.Bugs
--enable-languages=c,ada,c++,go,d,fortran,objc,obj-c++,m2 --prefix=/usr
--with-gcc-major-version-only --program-suffix=-12
--program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id
--libexecdir=/usr/lib --without-included-gettext --enable-threads=posix
--libdir=/usr/lib --enable-nls --enable-clocale=gnu --enable-libstdcxx-debug
--enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new
--enable-gnu-unique-object --disable-vtable-verify --enable-plugin
--enable-default-pie --with-system-zlib --enable-libphobos-checking=release
--with-target-system-zlib=auto --enable-objc-gc=auto --enable-multiarch
--disable-werror --enable-cet --with-arch-32=i686 --with-abi=m64
--with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic
--enable-offload-targets=nvptx-none=/build/gcc-12-Pa930Z/gcc-12-12.2.0/debian/tmp-nvptx/usr,amdgcn-amdhsa=/build/gcc-12-Pa930Z/gcc-12-12.2.0/debian/tmp-gcn/usr
--enable-offload-defaulted --without-cuda-driver --enable-checking=release
--build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 12.2.0 (Ubuntu 12.2.0-17ubuntu1)
