* [PATCH] block-qdict: Fix -Werror=maybe-uninitialized build failure
@ 2022-03-10 20:05 Murilo Opsfelder Araujo
2022-03-10 20:42 ` Daniel Henrique Barboza
2022-03-11 9:33 ` Markus Armbruster
0 siblings, 2 replies; 4+ messages in thread
From: Murilo Opsfelder Araujo @ 2022-03-10 20:05 UTC (permalink / raw)
To: qemu-devel
Cc: Kevin Wolf, qemu-block, Markus Armbruster, mopsfelder, muriloo,
Hanna Reitz
Building QEMU on Fedora 37 (Rawhide Prerelease) ppc64le failed with the
following error:
$ ../configure --prefix=/usr/local/qemu-disabletcg --target-list=ppc-softmmu,ppc64-softmmu --disable-tcg --disable-linux-user
...
$ make -j$(nproc)
...
FAILED: libqemuutil.a.p/qobject_block-qdict.c.o
cc -m64 -mlittle-endian -Ilibqemuutil.a.p -I. -I.. -Isubprojects/libvhost-user -I../subprojects/libvhost-user -Iqapi -Itrace -Iui -Iui/shader -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -I/usr/include/sysprof-4 -I/usr/include/lib
mount -I/usr/include/blkid -I/usr/include/gio-unix-2.0 -I/usr/include/p11-kit-1 -I/usr/include/pixman-1 -fdiagnostics-color=auto -Wall -Winvalid-pch -Werror -std=gnu11 -O2 -g -isystem /root/qemu/linux-headers -isystem linux-headers -iquote
. -iquote /root/qemu -iquote /root/qemu/include -iquote /root/qemu/disas/libvixl -pthread -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wundef -Wwrite
-strings -Wmissing-prototypes -fno-strict-aliasing -fno-common -fwrapv -Wold-style-declaration -Wold-style-definition -Wtype-limits -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers -Wempty-body -Wnested-externs -Wendif-label
s -Wexpansion-to-defined -Wimplicit-fallthrough=2 -Wno-missing-include-dirs -Wno-shift-negative-value -Wno-psabi -fstack-protector-strong -fPIE -MD -MQ libqemuutil.a.p/qobject_block-qdict.c.o -MF libqemuutil.a.p/qobject_block-qdict.c.o.d -
o libqemuutil.a.p/qobject_block-qdict.c.o -c ../qobject/block-qdict.c
In file included from /root/qemu/include/qapi/qmp/qdict.h:16,
from /root/qemu/include/block/qdict.h:13,
from ../qobject/block-qdict.c:11:
/root/qemu/include/qapi/qmp/qobject.h: In function ‘qdict_array_split’:
/root/qemu/include/qapi/qmp/qobject.h:49:17: error: ‘subqdict’ may be used uninitialized [-Werror=maybe-uninitialized]
49 | typeof(obj) _obj = (obj); \
| ^~~~
../qobject/block-qdict.c:227:16: note: ‘subqdict’ declared here
227 | QDict *subqdict;
| ^~~~~~~~
cc1: all warnings being treated as errors
Fix build failure by initializing the QDict variable with NULL.
Signed-off-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com>
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Hanna Reitz <hreitz@redhat.com>
Cc: Markus Armbruster <armbru@redhat.com>
---
qobject/block-qdict.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/qobject/block-qdict.c b/qobject/block-qdict.c
index 1487cc5dd8..b26524429c 100644
--- a/qobject/block-qdict.c
+++ b/qobject/block-qdict.c
@@ -224,7 +224,7 @@ void qdict_array_split(QDict *src, QList **dst)
for (i = 0; i < UINT_MAX; i++) {
QObject *subqobj;
bool is_subqdict;
- QDict *subqdict;
+ QDict *subqdict = NULL;
char indexstr[32], prefix[32];
size_t snprintf_ret;
--
2.35.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] block-qdict: Fix -Werror=maybe-uninitialized build failure
2022-03-10 20:05 [PATCH] block-qdict: Fix -Werror=maybe-uninitialized build failure Murilo Opsfelder Araujo
@ 2022-03-10 20:42 ` Daniel Henrique Barboza
2022-03-11 9:33 ` Markus Armbruster
1 sibling, 0 replies; 4+ messages in thread
From: Daniel Henrique Barboza @ 2022-03-10 20:42 UTC (permalink / raw)
To: Murilo Opsfelder Araujo, qemu-devel
Cc: Kevin Wolf, Hanna Reitz, mopsfelder, Markus Armbruster,
qemu-block
On 3/10/22 17:05, Murilo Opsfelder Araujo wrote:
> Building QEMU on Fedora 37 (Rawhide Prerelease) ppc64le failed with the
> following error:
>
> $ ../configure --prefix=/usr/local/qemu-disabletcg --target-list=ppc-softmmu,ppc64-softmmu --disable-tcg --disable-linux-user
> ...
> $ make -j$(nproc)
> ...
> FAILED: libqemuutil.a.p/qobject_block-qdict.c.o
> cc -m64 -mlittle-endian -Ilibqemuutil.a.p -I. -I.. -Isubprojects/libvhost-user -I../subprojects/libvhost-user -Iqapi -Itrace -Iui -Iui/shader -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -I/usr/include/sysprof-4 -I/usr/include/lib
> mount -I/usr/include/blkid -I/usr/include/gio-unix-2.0 -I/usr/include/p11-kit-1 -I/usr/include/pixman-1 -fdiagnostics-color=auto -Wall -Winvalid-pch -Werror -std=gnu11 -O2 -g -isystem /root/qemu/linux-headers -isystem linux-headers -iquote
> . -iquote /root/qemu -iquote /root/qemu/include -iquote /root/qemu/disas/libvixl -pthread -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wundef -Wwrite
> -strings -Wmissing-prototypes -fno-strict-aliasing -fno-common -fwrapv -Wold-style-declaration -Wold-style-definition -Wtype-limits -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers -Wempty-body -Wnested-externs -Wendif-label
> s -Wexpansion-to-defined -Wimplicit-fallthrough=2 -Wno-missing-include-dirs -Wno-shift-negative-value -Wno-psabi -fstack-protector-strong -fPIE -MD -MQ libqemuutil.a.p/qobject_block-qdict.c.o -MF libqemuutil.a.p/qobject_block-qdict.c.o.d -
> o libqemuutil.a.p/qobject_block-qdict.c.o -c ../qobject/block-qdict.c
> In file included from /root/qemu/include/qapi/qmp/qdict.h:16,
> from /root/qemu/include/block/qdict.h:13,
> from ../qobject/block-qdict.c:11:
> /root/qemu/include/qapi/qmp/qobject.h: In function ‘qdict_array_split’:
> /root/qemu/include/qapi/qmp/qobject.h:49:17: error: ‘subqdict’ may be used uninitialized [-Werror=maybe-uninitialized]
> 49 | typeof(obj) _obj = (obj); \
> | ^~~~
> ../qobject/block-qdict.c:227:16: note: ‘subqdict’ declared here
> 227 | QDict *subqdict;
> | ^~~~~~~~
> cc1: all warnings being treated as errors
>
> Fix build failure by initializing the QDict variable with NULL.
>
> Signed-off-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com>
> Cc: Kevin Wolf <kwolf@redhat.com>
> Cc: Hanna Reitz <hreitz@redhat.com>
> Cc: Markus Armbruster <armbru@redhat.com>
> ---
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
> qobject/block-qdict.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/qobject/block-qdict.c b/qobject/block-qdict.c
> index 1487cc5dd8..b26524429c 100644
> --- a/qobject/block-qdict.c
> +++ b/qobject/block-qdict.c
> @@ -224,7 +224,7 @@ void qdict_array_split(QDict *src, QList **dst)
> for (i = 0; i < UINT_MAX; i++) {
> QObject *subqobj;
> bool is_subqdict;
> - QDict *subqdict;
> + QDict *subqdict = NULL;
> char indexstr[32], prefix[32];
> size_t snprintf_ret;
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] block-qdict: Fix -Werror=maybe-uninitialized build failure
2022-03-10 20:05 [PATCH] block-qdict: Fix -Werror=maybe-uninitialized build failure Murilo Opsfelder Araujo
2022-03-10 20:42 ` Daniel Henrique Barboza
@ 2022-03-11 9:33 ` Markus Armbruster
2022-03-11 22:29 ` Murilo Opsfelder Araújo
1 sibling, 1 reply; 4+ messages in thread
From: Markus Armbruster @ 2022-03-11 9:33 UTC (permalink / raw)
To: Murilo Opsfelder Araujo
Cc: Kevin Wolf, Hanna Reitz, mopsfelder, qemu-devel, qemu-block
Murilo Opsfelder Araujo <muriloo@linux.ibm.com> writes:
> Building QEMU on Fedora 37 (Rawhide Prerelease) ppc64le failed with the
> following error:
>
> $ ../configure --prefix=/usr/local/qemu-disabletcg --target-list=ppc-softmmu,ppc64-softmmu --disable-tcg --disable-linux-user
> ...
> $ make -j$(nproc)
> ...
> FAILED: libqemuutil.a.p/qobject_block-qdict.c.o
> cc -m64 -mlittle-endian -Ilibqemuutil.a.p -I. -I.. -Isubprojects/libvhost-user -I../subprojects/libvhost-user -Iqapi -Itrace -Iui -Iui/shader -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -I/usr/include/sysprof-4 -I/usr/include/lib
> mount -I/usr/include/blkid -I/usr/include/gio-unix-2.0 -I/usr/include/p11-kit-1 -I/usr/include/pixman-1 -fdiagnostics-color=auto -Wall -Winvalid-pch -Werror -std=gnu11 -O2 -g -isystem /root/qemu/linux-headers -isystem linux-headers -iquote
> . -iquote /root/qemu -iquote /root/qemu/include -iquote /root/qemu/disas/libvixl -pthread -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wundef -Wwrite
> -strings -Wmissing-prototypes -fno-strict-aliasing -fno-common -fwrapv -Wold-style-declaration -Wold-style-definition -Wtype-limits -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers -Wempty-body -Wnested-externs -Wendif-label
> s -Wexpansion-to-defined -Wimplicit-fallthrough=2 -Wno-missing-include-dirs -Wno-shift-negative-value -Wno-psabi -fstack-protector-strong -fPIE -MD -MQ libqemuutil.a.p/qobject_block-qdict.c.o -MF libqemuutil.a.p/qobject_block-qdict.c.o.d -
> o libqemuutil.a.p/qobject_block-qdict.c.o -c ../qobject/block-qdict.c
> In file included from /root/qemu/include/qapi/qmp/qdict.h:16,
> from /root/qemu/include/block/qdict.h:13,
> from ../qobject/block-qdict.c:11:
> /root/qemu/include/qapi/qmp/qobject.h: In function ‘qdict_array_split’:
> /root/qemu/include/qapi/qmp/qobject.h:49:17: error: ‘subqdict’ may be used uninitialized [-Werror=maybe-uninitialized]
> 49 | typeof(obj) _obj = (obj); \
> | ^~~~
> ../qobject/block-qdict.c:227:16: note: ‘subqdict’ declared here
> 227 | QDict *subqdict;
> | ^~~~~~~~
> cc1: all warnings being treated as errors
>
> Fix build failure by initializing the QDict variable with NULL.
>
> Signed-off-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com>
> Cc: Kevin Wolf <kwolf@redhat.com>
> Cc: Hanna Reitz <hreitz@redhat.com>
> Cc: Markus Armbruster <armbru@redhat.com>
> ---
> qobject/block-qdict.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/qobject/block-qdict.c b/qobject/block-qdict.c
> index 1487cc5dd8..b26524429c 100644
> --- a/qobject/block-qdict.c
> +++ b/qobject/block-qdict.c
> @@ -224,7 +224,7 @@ void qdict_array_split(QDict *src, QList **dst)
> for (i = 0; i < UINT_MAX; i++) {
> QObject *subqobj;
> bool is_subqdict;
> - QDict *subqdict;
> + QDict *subqdict = NULL;
> char indexstr[32], prefix[32];
> size_t snprintf_ret;
The compiler's warning is actually spurious. Your patch is the
minimally invasive way to shut it up. But I wonder whether we can
make the code clearer instead. Let's have a look:
/*
* There may be either a single subordinate object (named
* "%u") or multiple objects (each with a key prefixed "%u."),
* but not both.
*/
if (!subqobj == !is_subqdict) {
break;
Because of this, ...
}
if (is_subqdict) {
... subqobj is non-null here, and ...
qdict_extract_subqdict(src, &subqdict, prefix);
assert(qdict_size(subqdict) > 0);
} else {
... null here.
qobject_ref(subqobj);
qdict_del(src, indexstr);
}
qlist_append_obj(*dst, subqobj ?: QOBJECT(subqdict));
What about this:
if (is_subqdict) {
qdict_extract_subqdict(src, &subqdict, prefix);
assert(qdict_size(subqdict) > 0);
qlist_append_obj(*dst, subqobj);
} else {
qobject_ref(subqobj);
qdict_del(src, indexstr);
qlist_append_obj(*dst, QOBJECT(subqdict));
}
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] block-qdict: Fix -Werror=maybe-uninitialized build failure
2022-03-11 9:33 ` Markus Armbruster
@ 2022-03-11 22:29 ` Murilo Opsfelder Araújo
0 siblings, 0 replies; 4+ messages in thread
From: Murilo Opsfelder Araújo @ 2022-03-11 22:29 UTC (permalink / raw)
To: Markus Armbruster
Cc: Kevin Wolf, Hanna Reitz, mopsfelder, qemu-devel, qemu-block
Hi, Markus.
On 3/11/22 06:33, Markus Armbruster wrote:
> Murilo Opsfelder Araujo <muriloo@linux.ibm.com> writes:
>
>> Building QEMU on Fedora 37 (Rawhide Prerelease) ppc64le failed with the
>> following error:
>>
>> $ ../configure --prefix=/usr/local/qemu-disabletcg --target-list=ppc-softmmu,ppc64-softmmu --disable-tcg --disable-linux-user
>> ...
>> $ make -j$(nproc)
>> ...
>> FAILED: libqemuutil.a.p/qobject_block-qdict.c.o
>> cc -m64 -mlittle-endian -Ilibqemuutil.a.p -I. -I.. -Isubprojects/libvhost-user -I../subprojects/libvhost-user -Iqapi -Itrace -Iui -Iui/shader -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -I/usr/include/sysprof-4 -I/usr/include/lib
>> mount -I/usr/include/blkid -I/usr/include/gio-unix-2.0 -I/usr/include/p11-kit-1 -I/usr/include/pixman-1 -fdiagnostics-color=auto -Wall -Winvalid-pch -Werror -std=gnu11 -O2 -g -isystem /root/qemu/linux-headers -isystem linux-headers -iquote
>> . -iquote /root/qemu -iquote /root/qemu/include -iquote /root/qemu/disas/libvixl -pthread -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=2 -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -Wstrict-prototypes -Wredundant-decls -Wundef -Wwrite
>> -strings -Wmissing-prototypes -fno-strict-aliasing -fno-common -fwrapv -Wold-style-declaration -Wold-style-definition -Wtype-limits -Wformat-security -Wformat-y2k -Winit-self -Wignored-qualifiers -Wempty-body -Wnested-externs -Wendif-label
>> s -Wexpansion-to-defined -Wimplicit-fallthrough=2 -Wno-missing-include-dirs -Wno-shift-negative-value -Wno-psabi -fstack-protector-strong -fPIE -MD -MQ libqemuutil.a.p/qobject_block-qdict.c.o -MF libqemuutil.a.p/qobject_block-qdict.c.o.d -
>> o libqemuutil.a.p/qobject_block-qdict.c.o -c ../qobject/block-qdict.c
>> In file included from /root/qemu/include/qapi/qmp/qdict.h:16,
>> from /root/qemu/include/block/qdict.h:13,
>> from ../qobject/block-qdict.c:11:
>> /root/qemu/include/qapi/qmp/qobject.h: In function ‘qdict_array_split’:
>> /root/qemu/include/qapi/qmp/qobject.h:49:17: error: ‘subqdict’ may be used uninitialized [-Werror=maybe-uninitialized]
>> 49 | typeof(obj) _obj = (obj); \
>> | ^~~~
>> ../qobject/block-qdict.c:227:16: note: ‘subqdict’ declared here
>> 227 | QDict *subqdict;
>> | ^~~~~~~~
>> cc1: all warnings being treated as errors
>>
>> Fix build failure by initializing the QDict variable with NULL.
>>
>> Signed-off-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com>
>> Cc: Kevin Wolf <kwolf@redhat.com>
>> Cc: Hanna Reitz <hreitz@redhat.com>
>> Cc: Markus Armbruster <armbru@redhat.com>
>> ---
>> qobject/block-qdict.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/qobject/block-qdict.c b/qobject/block-qdict.c
>> index 1487cc5dd8..b26524429c 100644
>> --- a/qobject/block-qdict.c
>> +++ b/qobject/block-qdict.c
>> @@ -224,7 +224,7 @@ void qdict_array_split(QDict *src, QList **dst)
>> for (i = 0; i < UINT_MAX; i++) {
>> QObject *subqobj;
>> bool is_subqdict;
>> - QDict *subqdict;
>> + QDict *subqdict = NULL;
>> char indexstr[32], prefix[32];
>> size_t snprintf_ret;
>
> The compiler's warning is actually spurious. Your patch is the
> minimally invasive way to shut it up. But I wonder whether we can
> make the code clearer instead. Let's have a look:
>
> /*
> * There may be either a single subordinate object (named
> * "%u") or multiple objects (each with a key prefixed "%u."),
> * but not both.
> */
> if (!subqobj == !is_subqdict) {
> break;
>
> Because of this, ...
>
> }
>
> if (is_subqdict) {
>
> ... subqobj is non-null here, and ...
>
> qdict_extract_subqdict(src, &subqdict, prefix);
> assert(qdict_size(subqdict) > 0);
> } else {
>
> ... null here.
>
> qobject_ref(subqobj);
> qdict_del(src, indexstr);
> }
>
> qlist_append_obj(*dst, subqobj ?: QOBJECT(subqdict));
>
> What about this:
>
> if (is_subqdict) {
> qdict_extract_subqdict(src, &subqdict, prefix);
> assert(qdict_size(subqdict) > 0);
> qlist_append_obj(*dst, subqobj);
> } else {
> qobject_ref(subqobj);
> qdict_del(src, indexstr);
> qlist_append_obj(*dst, QOBJECT(subqdict));
> }
>
The logic looks inverted but I think I got what you meant.
I've sent a v2 with changes that made the compiler happy and also passed check-unit tests.
Thank you!
--
Murilo
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-03-11 22:31 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2022-03-10 20:05 [PATCH] block-qdict: Fix -Werror=maybe-uninitialized build failure Murilo Opsfelder Araujo
2022-03-10 20:42 ` Daniel Henrique Barboza
2022-03-11 9:33 ` Markus Armbruster
2022-03-11 22:29 ` Murilo Opsfelder Araújo
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