| Message ID | f2aaec5b3c12a8512cd7078f3a5d1230906d80ea.1556650594.git.alistair.francis@wdc.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Fix some GCC 9 build warnings | expand |
Le 30/04/2019 à 22:09, Alistair Francis a écrit : > 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.francis@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..6de85d99e6 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 unalligned, so we ignore GCC warnings. > + */ > +#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); > You should move and use PRAGMA_DISABLE_PACKED_WARNING and PRAGMA_REENABLE_PACKED_WARNING from linux-user/qemu.h. It has laready been very well tested :) Thanks, Laurent
On 4/30/19 3:09 PM, 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.francis@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..6de85d99e6 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 unalligned, so we ignore GCC warnings. unaligned Aren't there other potential proposed patches floating around for this issue that do not involve messing with pragmas? > + */ > +#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); >
Le 30/04/2019 à 22:28, Laurent Vivier a écrit : > Le 30/04/2019 à 22:09, Alistair Francis a écrit : >> 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.francis@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..6de85d99e6 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 unalligned, so we ignore GCC warnings. >> + */ >> +#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); >> > > You should move and use PRAGMA_DISABLE_PACKED_WARNING and > PRAGMA_REENABLE_PACKED_WARNING from linux-user/qemu.h. > > It has laready been very well tested :) Oh, they are for clang and a false positive, so forget my comment (and the following one) Thanks, Laurent
On Tue, Apr 30, 2019 at 1:37 PM Eric Blake <eblake@redhat.com> wrote: > > On 4/30/19 3:09 PM, 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.francis@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..6de85d99e6 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 unalligned, so we ignore GCC warnings. > > unaligned Fixed. > > Aren't there other potential proposed patches floating around for this > issue that do not involve messing with pragmas? I'm not sure, I haven't seen anything. I'm more then open to a better fix, this is the best option I could think of. Alistair > > > + */ > > +#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); > > > > -- > Eric Blake, Principal Software Engineer > Red Hat, Inc. +1-919-301-3226 > Virtualization: qemu.org | libvirt.org >
diff --git a/hw/usb/dev-mtp.c b/hw/usb/dev-mtp.c index 99548b012d..6de85d99e6 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 unalligned, so we ignore GCC warnings. + */ +#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);
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.francis@wdc.com> --- hw/usb/dev-mtp.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)