[Qemu-devel] [PATCH] qapi-types.py: Fix enum struct sizes on i686

[Qemu-devel] [PATCH] qapi-types.py: Fix enum struct sizes on i686

[Cole Robinson]

Unlike other list types, enum wasn't adding any padding, which caused
a mismatch between the generated struct size and GenericList struct
size. More details in a678e26cbe89f7a27cbce794c2c2784571ee9d21

This crashed qemu if calling qmp query-tpm-types for example, which
upsets libvirt capabilities probing. Reproducer on i686:

(sleep 5; printf '{"execute":"qmp_capabilities"}\n{"execute":"query-tpm-types"}\n') | ./i386-softmmu/qemu-system-i386 -S -nodefaults -nographic -M none -qmp stdio

https://bugs.launchpad.net/qemu/+bug/1219207

Cc: qemu-stable@nongnu.org
Signed-off-by: Cole Robinson <crobinso@redhat.com>
---
 scripts/qapi-types.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/scripts/qapi-types.py b/scripts/qapi-types.py
index 5ee46ea..5d31b06 100644
--- a/scripts/qapi-types.py
+++ b/scripts/qapi-types.py
@@ -51,7 +51,10 @@ def generate_fwd_enum_struct(name, members):
     return mcgen('''
 typedef struct %(name)sList
 {
-    %(name)s value;
+    union {
+        %(name)s value;
+        uint64_t padding;
+    };
     struct %(name)sList *next;
 } %(name)sList;
 ''',
-- 
1.8.3.1

Re: [Qemu-devel] [PATCH] qapi-types.py: Fix enum struct sizes on i686

[Eric Blake]

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On 08/31/2013 04:36 PM, Cole Robinson wrote:
> Unlike other list types, enum wasn't adding any padding, which caused
> a mismatch between the generated struct size and GenericList struct
> size. More details in a678e26cbe89f7a27cbce794c2c2784571ee9d21
> 
> This crashed qemu if calling qmp query-tpm-types for example, which
> upsets libvirt capabilities probing. Reproducer on i686:
> 
> (sleep 5; printf '{"execute":"qmp_capabilities"}\n{"execute":"query-tpm-types"}\n') | ./i386-softmmu/qemu-system-i386 -S -nodefaults -nographic -M none -qmp stdio
> 
> https://bugs.launchpad.net/qemu/+bug/1219207
> 
> Cc: qemu-stable@nongnu.org
> Signed-off-by: Cole Robinson <crobinso@redhat.com>
> ---
>  scripts/qapi-types.py | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 

Reviewed-by: Eric Blake <eblake@redhat.com>

> -    %(name)s value;
> +    union {
> +        %(name)s value;
> +        uint64_t padding;
> +    };

Am I right that anonymous unions are only a C11 feature (not C99)?  But
you are just copying and pasting from the other uses in this file, so
it's not a problem.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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Re: [Qemu-devel] [Qemu-stable] [PATCH] qapi-types.py: Fix enum struct sizes on i686

[Doug Goldstein]

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On Sat, Aug 31, 2013 at 9:07 PM, Eric Blake <eblake@redhat.com> wrote:

> On 08/31/2013 04:36 PM, Cole Robinson wrote:
> > Unlike other list types, enum wasn't adding any padding, which caused
> > a mismatch between the generated struct size and GenericList struct
> > size. More details in a678e26cbe89f7a27cbce794c2c2784571ee9d21
> >
> > This crashed qemu if calling qmp query-tpm-types for example, which
> > upsets libvirt capabilities probing. Reproducer on i686:
> >
> > (sleep 5; printf
> '{"execute":"qmp_capabilities"}\n{"execute":"query-tpm-types"}\n') |
> ./i386-softmmu/qemu-system-i386 -S -nodefaults -nographic -M none -qmp stdio
> >
> > https://bugs.launchpad.net/qemu/+bug/1219207
> >
> > Cc: qemu-stable@nongnu.org
> > Signed-off-by: Cole Robinson <crobinso@redhat.com>
> > ---
> >  scripts/qapi-types.py | 5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> >
>
> Reviewed-by: Eric Blake <eblake@redhat.com>
>
> > -    %(name)s value;
> > +    union {
> > +        %(name)s value;
> > +        uint64_t padding;
> > +    };
>
> Am I right that anonymous unions are only a C11 feature (not C99)?  But
> you are just copying and pasting from the other uses in this file, so
> it's not a problem.
>
>
Yes, they're a C11-ism. But they appear in gnu99, not sure as to what GCC
added them but I know GCC 3.2 didn't have them.

-- 
Doug Goldstein

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Re: [Qemu-devel] [PATCH] qapi-types.py: Fix enum struct sizes on i686

[Richard W.M. Jones]

On Sat, Aug 31, 2013 at 06:36:17PM -0400, Cole Robinson wrote:
> Unlike other list types, enum wasn't adding any padding, which caused
> a mismatch between the generated struct size and GenericList struct
> size. More details in a678e26cbe89f7a27cbce794c2c2784571ee9d21
> 
> This crashed qemu if calling qmp query-tpm-types for example, which
> upsets libvirt capabilities probing. Reproducer on i686:
> 
> (sleep 5; printf '{"execute":"qmp_capabilities"}\n{"execute":"query-tpm-types"}\n') | ./i386-softmmu/qemu-system-i386 -S -nodefaults -nographic -M none -qmp stdio
> 
> https://bugs.launchpad.net/qemu/+bug/1219207
> 
> Cc: qemu-stable@nongnu.org
> Signed-off-by: Cole Robinson <crobinso@redhat.com>

Works for me, so you can add:

Tested-by: Richard W.M. Jones <rjones@redhat.com>

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Fedora Windows cross-compiler. Compile Windows programs, test, and
build Windows installers. Over 100 libraries supported.
http://fedoraproject.org/wiki/MinGW

Re: [Qemu-devel] [PATCH] qapi-types.py: Fix enum struct sizes on i686

[Luiz Capitulino]

On Sat, 31 Aug 2013 18:36:17 -0400
Cole Robinson <crobinso@redhat.com> wrote:

> Unlike other list types, enum wasn't adding any padding, which caused
> a mismatch between the generated struct size and GenericList struct
> size. More details in a678e26cbe89f7a27cbce794c2c2784571ee9d21
> 
> This crashed qemu if calling qmp query-tpm-types for example, which
> upsets libvirt capabilities probing. Reproducer on i686:
> 
> (sleep 5; printf '{"execute":"qmp_capabilities"}\n{"execute":"query-tpm-types"}\n') | ./i386-softmmu/qemu-system-i386 -S -nodefaults -nographic -M none -qmp stdio
> 
> https://bugs.launchpad.net/qemu/+bug/1219207
> 
> Cc: qemu-stable@nongnu.org
> Signed-off-by: Cole Robinson <crobinso@redhat.com>

Applied to the qmp branch, thanks.

> ---
>  scripts/qapi-types.py | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/scripts/qapi-types.py b/scripts/qapi-types.py
> index 5ee46ea..5d31b06 100644
> --- a/scripts/qapi-types.py
> +++ b/scripts/qapi-types.py
> @@ -51,7 +51,10 @@ def generate_fwd_enum_struct(name, members):
>      return mcgen('''
>  typedef struct %(name)sList
>  {
> -    %(name)s value;
> +    union {
> +        %(name)s value;
> +        uint64_t padding;
> +    };
>      struct %(name)sList *next;
>  } %(name)sList;
>  ''',