On Mon, 2021-07-19 at 19:19 +0100, Daniel P. Berrangé wrote:

When building with sanitizers on Fedora we get a wierd error

weird

message

In file included from /usr/include/string.h:519,                  from ../src/internal.h:28,                  from ../src/util/virsocket.h:21,                  from ../src/util/virsocketaddr.h:21,                  from ../src/util/virnetdevip.h:21,                  from ../src/util/virnetdevip.c:21: In function ‘memcpy’,     inlined from ‘virNetDevGetifaddrsAddress’ at ../src/util/virnetdevip.c:702:13,     inlined from ‘virNetDevIPAddrGet’ at ../src/util/virnetdevip.c:754:16: /usr/include/bits/string_fortified.h:29:10: error: ‘__builtin_memcpy’ offset [2, 27] from the object at ‘addr’ is out of the bounds of referenced subobject ‘ss_family’ with type ‘short unsigned int’ at offset 0 [-Werror=array-bounds]    29 |   return __builtin___memcpy_chk (__dest, __src, __len,       |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~    30 |                                  __glibc_objsize0 (__dest));       |                                  ~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from /usr/include/bits/socket.h:175,                  from /usr/include/sys/socket.h:33,                  from ../src/util/virsocket.h:66,                  from ../src/util/virsocketaddr.h:21,                  from ../src/util/virnetdevip.h:21,                  from ../src/util/virnetdevip.c:21: ../src/util/virnetdevip.c: In function ‘virNetDevIPAddrGet’: /usr/include/bits/socket.h:193:5: note: subobject ‘ss_family’ declared here   193 |     __SOCKADDR_COMMON (ss_);    /* Address family, etc.  */       |     ^~~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors

The code is correct, and this only happens when building at -O2.

The docs for -Warray-bounds say that a value of "2" is known to be liable to generate false positives. Rather than downgrade the check everywhere, we do it selectively for sanitizers.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

Reviewed-by: Tim Wiederhake <twiederh@redhat.com>

---  meson.build | 7 ++++++-  1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/meson.build b/meson.build index ca4291e37a..d4c142eebb 100644 --- a/meson.build +++ b/meson.build @@ -227,6 +227,11 @@ alloc_max = run_command(  # sanitizer instrumentation may enlarge stack frames  stack_frame_size = get_option('b_sanitize') == 'none' ? 4096 : 8192   +# array_bounds=2 check triggers false positive on some GCC +# versions when using sanitizers. Seen on Fedora 34 with +# GCC 11.1.1 +array_bounds = get_option('b_sanitize') == 'none' ? 2 : 1 +  cc_flags += [    '-fasynchronous-unwind-tables',    '-fexceptions', @@ -238,7 +243,7 @@ cc_flags += [    '-Waggressive-loop-optimizations',    '-Walloc-size-larger-than=@0@'.format(alloc_max.stdout().strip()),    '-Walloca', -  '-Warray-bounds=2', +  '-Warray-bounds=@0@'.format(array_bounds),    '-Wattribute-alias=2',    '-Wattribute-warning',    '-Wattributes',