https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578
Andrew Cooper <andrew.cooper3 at citrix dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |andrew.cooper3 at citrix dot
com
--- Comment #14 from Andrew Cooper <andrew.cooper3 at citrix dot com> ---
I too have had what appears to be this bug, raised against a microkernel
project.
The logic is a test case involving interactions at the x86-64 lower canonical
boundary, and reads like so:
...
uint64_t *ptr = (void *)0x00007ffffffffff8ul;
memcpy(ptr, "\x90\x90\xf\xbxen\x90", 8);
...
This yields:
include/xtf/libc.h:36:37: error: ‘__builtin_memcpy’ offset [0, 7] is out of
the bounds [0, 0] [-Werror=array-bounds]
36 | #define memcpy(d, s, n) __builtin_memcpy(d, s, n)
| ^~~~~~~~~~~~~~~~~~~~~~~~~
main.c:81:5: note: in expansion of macro ‘memcpy’
81 | memcpy(ptr, "\x90\x90\xf\xbxen\x90", 8);
| ^~~~~~
It is worth pointing out that it is common for kernels to have some virtual
addresses derived from compile-time constants, notably the fixmap and
frametable.
