On Tue, Apr 30, 2019 at 11:28:41PM +0000, Alistair Francis wrote: > Fix this warning with GCC 9 on Fedora 30: > hw/usb/dev-mtp.c:1715:36: error: taking address of packed member of ‘struct > <anonymous>’ may result in an unaligned pointer value > [-Werror=address-of-packed-member] > 1715 | dataset->filename); > | ~~~~~~~^~~~~~~~~~ > > Signed-off-by: Alistair Francis <alistair.fran...@wdc.com> > --- > hw/usb/dev-mtp.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/hw/usb/dev-mtp.c b/hw/usb/dev-mtp.c > index 99548b012d..8233beacab 100644 > --- a/hw/usb/dev-mtp.c > +++ b/hw/usb/dev-mtp.c > @@ -1711,9 +1711,22 @@ static void usb_mtp_write_metadata(MTPState *s, > uint64_t dlen) > assert(!s->write_pending); > assert(p != NULL); > > +/* > + * We are about to access a packed struct. We are confident that the pointer > + * address won't be unaligned, so we ignore GCC warnings. > + */
The data is mis-aligned as we're accessing an int16 array that is immediately following an int8 field in a packed struct This problem is fixed by the following series which Gerd has in the USB queue: https://lists.gnu.org/archive/html/qemu-devel/2019-04/msg02524.html > +#if defined(CONFIG_PRAGMA_DIAGNOSTIC_AVAILABLE) && QEMU_GNUC_PREREQ(9, 0) > +#pragma GCC diagnostic push > +#pragma GCC diagnostic ignored "-Waddress-of-packed-member" > +#endif > + > filename = utf16_to_str(MIN(dataset->length, filename_chars), > dataset->filename); > > +#if defined(CONFIG_PRAGMA_DIAGNOSTIC_AVAILABLE) && QEMU_GNUC_PREREQ(9, 0) > +#pragma GCC diagnostic pop > +#endif > + > if (strchr(filename, '/')) { > usb_mtp_queue_result(s, RES_PARAMETER_NOT_SUPPORTED, d->trans, > 0, 0, 0, 0); Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|