On Tue, Jul 20, 2021 at 07:31:20PM -0300, Jose R. Ziviani wrote:
> module_object_class_by_name() calls module_load_qom_one if the object
> is provided by a dynamically linked library. Such library might not be
> available at this moment - for instance, it can be a package not yet
> installed. Thus, instead of assert error messages, this patch outputs
> more friendly messages.
>
> Current error messages:
> $ ./qemu-system-x86_64 -machine q35 -accel tcg -kernel /boot/vmlinuz
> ...
> ERROR:../accel/accel-softmmu.c:82:accel_init_ops_interfaces: assertion
> failed: (ops != NULL)
> Bail out! ERROR:../accel/accel-softmmu.c:82:accel_init_ops_interfaces:
> assertion failed: (ops != NULL)
> [1] 31964 IOT instruction (core dumped) ./qemu-system-x86_64 ...
>
> New error message:
> $ ./qemu-system-x86_64 -machine q35 -accel tcg -kernel /boot/vmlinuz
> accel-tcg-x86_64 module is missing, install the package or config the library
> path correctly.
>
> Or with other modules, when possible:
> $ ./qemu-system-x86_64 -machine q35 -accel kvm -kernel /boot/vmlinuz -vga qxl
> ✹
> hw-display-qxl module is missing, install the package or config the library
> path correctly.
> qemu-system-x86_64: QXL VGA not available
>
> $ make check
> ...
> Running test qtest-x86_64/test-filter-mirror
> Running test qtest-x86_64/endianness-test
> accel-qtest-x86_64 module is missing, install the package or config the
> library path correctly.
> accel-qtest-x86_64 module is missing, install the package or config the
> library path correctly.
> accel-qtest-x86_64 module is missing, install the package or config the
> library path correctly.
> accel-qtest-x86_64 module is missing, install the package or config the
> library path correctly.
> accel-qtest-x86_64 module is missing, install the package or config the
> library path correctly.
> accel-tcg-x86_64 module is missing, install the package or config the library
> path correctly.
> ...
>
> Signed-off-by: Jose R. Ziviani <jzivi...@suse.de>
> ---
> accel/accel-softmmu.c | 5 ++++-
> qom/object.c | 9 +++++++++
> 2 files changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/accel/accel-softmmu.c b/accel/accel-softmmu.c
> index 67276e4f52..52449ac2d0 100644
> --- a/accel/accel-softmmu.c
> +++ b/accel/accel-softmmu.c
> @@ -79,7 +79,10 @@ void accel_init_ops_interfaces(AccelClass *ac)
> * all accelerators need to define ops, providing at least a mandatory
> * non-NULL create_vcpu_thread operation.
> */
> - g_assert(ops != NULL);
> + if (ops == NULL) {
> + exit(1);
> + }
> +
> if (ops->ops_init) {
> ops->ops_init(ops);
> }
> diff --git a/qom/object.c b/qom/object.c
> index 6a01d56546..3a170ea9df 100644
> --- a/qom/object.c
> +++ b/qom/object.c
> @@ -10,6 +10,7 @@
> * See the COPYING file in the top-level directory.
> */
>
> +#include "qemu/module.h"
> #include "qemu/osdep.h"
> #include "hw/qdev-core.h"
> #include "qapi/error.h"
> @@ -1031,8 +1032,16 @@ ObjectClass *module_object_class_by_name(const char
> *typename)
> oc = object_class_by_name(typename);
> #ifdef CONFIG_MODULES
> if (!oc) {
> + const char *module_name = module_get_name_from_obj(typename);
> module_load_qom_one(typename);
> oc = object_class_by_name(typename);
> + if (!oc && module_name) {
> + if (!module_is_loaded(module_name)) {
> + fprintf(stderr, "%s module is missing, install the "
> + "package or config the library path "
> + "correctly.\n", module_name);
> + }
> + }
> }
Introducing a call to module_is_loaded is feels like it isn't really
addressing the root cause.
The error scenario here exists because module_load_qom_one() can
fail to load the requested module. We don't detect that failure
because module_load_qom_one() is "void" for some reason. There
are several possible causes of failure and missing file on disk
is only one of them.
This general error message about "module_name" being missing is
misleading when there are dependancies involved. "module_name"
may well exist, but something it depends on might be missing.
Or the modules might have been built from wrong QEMU and be
unable to be dlopened despite existing.
I think we need to fix module_load_qom_one() so that it can
actually report failure via an "Error **errp" parameter.
This will also entail fixing a number of methods it in turn
calls.
Regards,
Daniel
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