From: "Jose R. Ziviani" <jziviani@suse.de>
To: Claudio Fontana <cfontana@suse.de>
Cc: pbonzini@redhat.com, "Philippe Mathieu-Daudé" <f4bug@amsat.org>,
richard.henderson@linaro.org, qemu-devel@nongnu.org,
kraxel@redhat.com
Subject: Re: [PATCH v2 1/1] modules: Improve error message when module is not found
Date: Fri, 23 Jul 2021 10:50:41 -0300 [thread overview]
Message-ID: <YPrJMTF+3lfeNdC5@pizza> (raw)
In-Reply-To: <c26fc6f4-341f-c66f-5384-c811e1342891@suse.de>
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On Fri, Jul 23, 2021 at 11:41:19AM +0200, Claudio Fontana wrote:
> On 7/23/21 12:09 AM, Jose R. Ziviani wrote:
> > When a module is not found, specially accelerators, QEMU displays
> > a error message that not easy to understand[1]. This patch improves
> > the readability by offering a user-friendly message[2].
> >
> > This patch also moves the accelerator ops check to runtine (instead
> > of the original g_assert) because it works better with dynamic
> > modules.
> >
> > [1] qemu-system-x86_64 -accel tcg
> > 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)
> > 31964 IOT instruction (core dumped) ./qemu-system-x86_64 ...
> >
> > [2] qemu-system-x86_64 -accel tcg
> > accel-tcg-x86_64 module is missing, install the package or config the library path correctly.
> >
> > Signed-off-by: Jose R. Ziviani <jziviani@suse.de>
> > ---
> > accel/accel-softmmu.c | 5 ++++-
> > util/module.c | 14 ++++++++------
> > 2 files changed, 12 insertions(+), 7 deletions(-)
> >
> > 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);
> > + }
> > +
>
>
> Ah, again, why?
> This change looks wrong to me,
>
> the ops code should be present when ops interfaces are initialized:
> it should be a code level assertion, as it has to do with the proper order of initializations in QEMU,
>
> why would we want to do anything else but to assert here?
>
> Am I blind to something obvious?
Hello!
Thank you for reviewing it!
The problem is that if your TCG module is not installed and you start
QEMU like:
./qemu-system-x86_64 -accel tcg
You'll get the error message + a crash with a core dump:
accel-tcg-x86_64 module is missing, install the package or config the library path correctly.
**
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] 5740 IOT instruction (core dumped) ./qemu-system-x86_64 -accel tcg
I was digging a little bit more in order to move this responsibility to
module.c but there isn't enough information there to safely exit() in
all situations that a module may be loaded. As Gerd mentioned, more work
is needed in order to achieve that.
However, it's not nice to have a crash due to an optional module missing.
It's specially confusing because TCG has always been native. Considering
also that we're already in hard freeze for 6.1, I thought to have this
simpler check instead.
What do you think if we have something like:
/* FIXME: this isn't the right place to handle a missing module and
must be reverted when the module refactoring is completely done */
#ifdef CONFIG_MODULES
if (ops == NULL) {
exit(1);
}
#else
g_assert(ops != NULL);
#endif
Regards!
>
> > if (ops->ops_init) {
> > ops->ops_init(ops);
> > }
> > diff --git a/util/module.c b/util/module.c
> > index 6bb4ad915a..268a8563fd 100644
> > --- a/util/module.c
> > +++ b/util/module.c
> > @@ -206,13 +206,10 @@ static int module_load_file(const char *fname, bool mayfail, bool export_symbols
> > out:
> > return ret;
> > }
> > -#endif
> >
> > bool module_load_one(const char *prefix, const char *lib_name, bool mayfail)
> > {
> > bool success = false;
> > -
> > -#ifdef CONFIG_MODULES
> > char *fname = NULL;
> > #ifdef CONFIG_MODULE_UPGRADES
> > char *version_dir;
> > @@ -300,6 +297,9 @@ bool module_load_one(const char *prefix, const char *lib_name, bool mayfail)
> >
> > if (!success) {
> > g_hash_table_remove(loaded_modules, module_name);
> > + fprintf(stderr, "%s module is missing, install the "
> > + "package or config the library path "
> > + "correctly.\n", module_name);
> > g_free(module_name);
> > }
> >
> > @@ -307,12 +307,9 @@ bool module_load_one(const char *prefix, const char *lib_name, bool mayfail)
> > g_free(dirs[i]);
> > }
> >
> > -#endif
> > return success;
> > }
> >
> > -#ifdef CONFIG_MODULES
> > -
> > static bool module_loaded_qom_all;
> >
> > void module_load_qom_one(const char *type)
> > @@ -384,4 +381,9 @@ void qemu_load_module_for_opts(const char *group) {}
> > void module_load_qom_one(const char *type) {}
> > void module_load_qom_all(void) {}
> >
> > +bool module_load_one(const char *prefix, const char *lib_name, bool mayfail)
> > +{
> > + return false;
> > +}
> > +
> > #endif
> >
>
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next prev parent reply other threads:[~2021-07-23 13:51 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-22 22:09 [PATCH v2 0/1] Improve module accelerator error message Jose R. Ziviani
2021-07-22 22:09 ` [PATCH v2 1/1] modules: Improve error message when module is not found Jose R. Ziviani
2021-07-23 6:25 ` Gerd Hoffmann
2021-07-23 8:04 ` Claudio Fontana
2021-07-23 8:28 ` Markus Armbruster
2021-07-23 8:32 ` Claudio Fontana
2021-07-23 9:41 ` Claudio Fontana
2021-07-23 9:52 ` Gerd Hoffmann
2021-07-23 11:20 ` Claudio Fontana
2021-07-23 12:20 ` Claudio Fontana
2021-07-23 12:48 ` Gerd Hoffmann
2021-07-29 9:14 ` modular tcg (was: Re: [PATCH v2 1/1] modules: Improve error message when module is not) found Gerd Hoffmann
2021-07-29 9:40 ` modular tcg Claudio Fontana
2021-07-29 10:26 ` Gerd Hoffmann
2021-07-29 10:42 ` Claudio Fontana
2021-07-29 9:42 ` Claudio Fontana
2021-07-29 10:29 ` Gerd Hoffmann
2021-07-29 10:44 ` Claudio Fontana
2021-07-29 11:34 ` Philippe Mathieu-Daudé
2021-07-29 11:39 ` Claudio Fontana
2021-07-29 14:22 ` Claudio Fontana
2021-07-29 14:59 ` Philippe Mathieu-Daudé
2021-07-29 16:35 ` Claudio Fontana
2021-07-29 16:40 ` modular tcg (was: Re: [PATCH v2 1/1] modules: Improve error message when module is not) found Paolo Bonzini
2021-07-30 9:05 ` modular tcg Gerd Hoffmann
2021-07-30 10:02 ` Claudio Fontana
2022-09-02 9:50 ` modular tcg (was: Re: [PATCH v2 1/1] modules: Improve error message when module is not) found Claudio Fontana
2021-07-23 13:50 ` Jose R. Ziviani [this message]
2021-07-23 14:02 ` [PATCH v2 1/1] modules: Improve error message when module is not found Claudio Fontana
2021-07-23 14:14 ` Philippe Mathieu-Daudé
2021-07-23 14:36 ` Jose R. Ziviani
2021-07-23 15:27 ` Claudio Fontana
2021-07-23 15:46 ` Jose R. Ziviani
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