* [PATCH] qom-qmp-cmds: fix two memleaks in qmp_object_add
@ 2020-03-09 9:22 Pan Nengyuan
2020-03-09 9:51 ` Igor Mammedov
2020-03-09 10:06 ` Markus Armbruster
0 siblings, 2 replies; 6+ messages in thread
From: Pan Nengyuan @ 2020-03-09 9:22 UTC (permalink / raw)
To: pbonzini, berrange, ehabkost
Cc: zhang.zhanghailiang, Pan Nengyuan, qemu-devel, euler.robot
'type/id' forgot to free in qmp_object_add, this patch fix that.
The leak stack:
Direct leak of 84 byte(s) in 6 object(s) allocated from:
#0 0x7fe2a5ebf768 in __interceptor_malloc (/lib64/libasan.so.5+0xef768)
#1 0x7fe2a5044445 in g_malloc (/lib64/libglib-2.0.so.0+0x52445)
#2 0x7fe2a505dd92 in g_strdup (/lib64/libglib-2.0.so.0+0x6bd92)
#3 0x56344954e692 in qmp_object_add /mnt/sdb/qemu-new/qemu_test/qemu/qom/qom-qmp-cmds.c:258
#4 0x563449960f5a in do_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:132
#5 0x563449960f5a in qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:175
#6 0x563449498a30 in monitor_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:145
#7 0x56344949a64f in monitor_qmp_bh_dispatcher /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:234
#8 0x563449a92a3a in aio_bh_call /mnt/sdb/qemu-new/qemu_test/qemu/util/async.c:136
Direct leak of 54 byte(s) in 6 object(s) allocated from:
#0 0x7fe2a5ebf768 in __interceptor_malloc (/lib64/libasan.so.5+0xef768)
#1 0x7fe2a5044445 in g_malloc (/lib64/libglib-2.0.so.0+0x52445)
#2 0x7fe2a505dd92 in g_strdup (/lib64/libglib-2.0.so.0+0x6bd92)
#3 0x56344954e6c4 in qmp_object_add /mnt/sdb/qemu-new/qemu_test/qemu/qom/qom-qmp-cmds.c:267
#4 0x563449960f5a in do_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:132
#5 0x563449960f5a in qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:175
#6 0x563449498a30 in monitor_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:145
#7 0x56344949a64f in monitor_qmp_bh_dispatcher /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:234
#8 0x563449a92a3a in aio_bh_call /mnt/sdb/qemu-new/qemu_test/qemu/util/async.c:136
Fixes: 5f07c4d60d091320186e7b0edaf9ed2cc16b2d1e
Reported-by: Euler Robot <euler.robot@huawei.com>
Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
---
qom/qom-qmp-cmds.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/qom/qom-qmp-cmds.c b/qom/qom-qmp-cmds.c
index 49db926fcc..ac59ba1aa8 100644
--- a/qom/qom-qmp-cmds.c
+++ b/qom/qom-qmp-cmds.c
@@ -247,8 +247,8 @@ void qmp_object_add(QDict *qdict, QObject **ret_data, Error **errp)
QDict *pdict;
Visitor *v;
Object *obj;
- const char *type;
- const char *id;
+ g_autofree const char *type = NULL;
+ g_autofree const char *id = NULL;
type = qdict_get_try_str(qdict, "qom-type");
if (!type) {
--
2.18.2
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] qom-qmp-cmds: fix two memleaks in qmp_object_add
2020-03-09 9:22 [PATCH] qom-qmp-cmds: fix two memleaks in qmp_object_add Pan Nengyuan
@ 2020-03-09 9:51 ` Igor Mammedov
2020-03-09 10:15 ` Daniel P. Berrangé
2020-03-09 10:17 ` Pan Nengyuan
2020-03-09 10:06 ` Markus Armbruster
1 sibling, 2 replies; 6+ messages in thread
From: Igor Mammedov @ 2020-03-09 9:51 UTC (permalink / raw)
To: Pan Nengyuan
Cc: berrange, ehabkost, qemu-devel, euler.robot, pbonzini,
zhang.zhanghailiang
On Mon, 9 Mar 2020 17:22:12 +0800
Pan Nengyuan <pannengyuan@huawei.com> wrote:
> 'type/id' forgot to free in qmp_object_add, this patch fix that.
>
> The leak stack:
> Direct leak of 84 byte(s) in 6 object(s) allocated from:
> #0 0x7fe2a5ebf768 in __interceptor_malloc (/lib64/libasan.so.5+0xef768)
> #1 0x7fe2a5044445 in g_malloc (/lib64/libglib-2.0.so.0+0x52445)
> #2 0x7fe2a505dd92 in g_strdup (/lib64/libglib-2.0.so.0+0x6bd92)
> #3 0x56344954e692 in qmp_object_add /mnt/sdb/qemu-new/qemu_test/qemu/qom/qom-qmp-cmds.c:258
> #4 0x563449960f5a in do_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:132
> #5 0x563449960f5a in qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:175
> #6 0x563449498a30 in monitor_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:145
> #7 0x56344949a64f in monitor_qmp_bh_dispatcher /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:234
> #8 0x563449a92a3a in aio_bh_call /mnt/sdb/qemu-new/qemu_test/qemu/util/async.c:136
>
> Direct leak of 54 byte(s) in 6 object(s) allocated from:
> #0 0x7fe2a5ebf768 in __interceptor_malloc (/lib64/libasan.so.5+0xef768)
> #1 0x7fe2a5044445 in g_malloc (/lib64/libglib-2.0.so.0+0x52445)
> #2 0x7fe2a505dd92 in g_strdup (/lib64/libglib-2.0.so.0+0x6bd92)
> #3 0x56344954e6c4 in qmp_object_add /mnt/sdb/qemu-new/qemu_test/qemu/qom/qom-qmp-cmds.c:267
> #4 0x563449960f5a in do_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:132
> #5 0x563449960f5a in qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:175
> #6 0x563449498a30 in monitor_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:145
> #7 0x56344949a64f in monitor_qmp_bh_dispatcher /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:234
> #8 0x563449a92a3a in aio_bh_call /mnt/sdb/qemu-new/qemu_test/qemu/util/async.c:136
>
> Fixes: 5f07c4d60d091320186e7b0edaf9ed2cc16b2d1e
> Reported-by: Euler Robot <euler.robot@huawei.com>
> Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
> ---
> qom/qom-qmp-cmds.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/qom/qom-qmp-cmds.c b/qom/qom-qmp-cmds.c
> index 49db926fcc..ac59ba1aa8 100644
> --- a/qom/qom-qmp-cmds.c
> +++ b/qom/qom-qmp-cmds.c
> @@ -247,8 +247,8 @@ void qmp_object_add(QDict *qdict, QObject **ret_data, Error **errp)
> QDict *pdict;
> Visitor *v;
> Object *obj;
> - const char *type;
> - const char *id;
> + g_autofree const char *type = NULL;
> + g_autofree const char *id = NULL;
not sure that's it's correct
qdict_get_try_str() returns the reference to a string within
the QDict, so caller who provided qdict should take care of
freeing it.
>
> type = qdict_get_try_str(qdict, "qom-type");
> if (!type) {
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] qom-qmp-cmds: fix two memleaks in qmp_object_add
2020-03-09 9:22 [PATCH] qom-qmp-cmds: fix two memleaks in qmp_object_add Pan Nengyuan
2020-03-09 9:51 ` Igor Mammedov
@ 2020-03-09 10:06 ` Markus Armbruster
1 sibling, 0 replies; 6+ messages in thread
From: Markus Armbruster @ 2020-03-09 10:06 UTC (permalink / raw)
To: Pan Nengyuan
Cc: Kevin Wolf, berrange, ehabkost, qemu-devel, euler.robot, pbonzini,
zhang.zhanghailiang
Cc'ing Kevin in the hope of a review.
Pan Nengyuan <pannengyuan@huawei.com> writes:
> 'type/id' forgot to free in qmp_object_add, this patch fix that.
>
> The leak stack:
> Direct leak of 84 byte(s) in 6 object(s) allocated from:
> #0 0x7fe2a5ebf768 in __interceptor_malloc (/lib64/libasan.so.5+0xef768)
> #1 0x7fe2a5044445 in g_malloc (/lib64/libglib-2.0.so.0+0x52445)
> #2 0x7fe2a505dd92 in g_strdup (/lib64/libglib-2.0.so.0+0x6bd92)
> #3 0x56344954e692 in qmp_object_add /mnt/sdb/qemu-new/qemu_test/qemu/qom/qom-qmp-cmds.c:258
> #4 0x563449960f5a in do_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:132
> #5 0x563449960f5a in qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:175
> #6 0x563449498a30 in monitor_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:145
> #7 0x56344949a64f in monitor_qmp_bh_dispatcher /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:234
> #8 0x563449a92a3a in aio_bh_call /mnt/sdb/qemu-new/qemu_test/qemu/util/async.c:136
>
> Direct leak of 54 byte(s) in 6 object(s) allocated from:
> #0 0x7fe2a5ebf768 in __interceptor_malloc (/lib64/libasan.so.5+0xef768)
> #1 0x7fe2a5044445 in g_malloc (/lib64/libglib-2.0.so.0+0x52445)
> #2 0x7fe2a505dd92 in g_strdup (/lib64/libglib-2.0.so.0+0x6bd92)
> #3 0x56344954e6c4 in qmp_object_add /mnt/sdb/qemu-new/qemu_test/qemu/qom/qom-qmp-cmds.c:267
> #4 0x563449960f5a in do_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:132
> #5 0x563449960f5a in qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:175
> #6 0x563449498a30 in monitor_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:145
> #7 0x56344949a64f in monitor_qmp_bh_dispatcher /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:234
> #8 0x563449a92a3a in aio_bh_call /mnt/sdb/qemu-new/qemu_test/qemu/util/async.c:136
>
> Fixes: 5f07c4d60d091320186e7b0edaf9ed2cc16b2d1e
> Reported-by: Euler Robot <euler.robot@huawei.com>
> Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
> ---
> qom/qom-qmp-cmds.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/qom/qom-qmp-cmds.c b/qom/qom-qmp-cmds.c
> index 49db926fcc..ac59ba1aa8 100644
> --- a/qom/qom-qmp-cmds.c
> +++ b/qom/qom-qmp-cmds.c
> @@ -247,8 +247,8 @@ void qmp_object_add(QDict *qdict, QObject **ret_data, Error **errp)
> QDict *pdict;
> Visitor *v;
> Object *obj;
> - const char *type;
> - const char *id;
> + g_autofree const char *type = NULL;
> + g_autofree const char *id = NULL;
>
> type = qdict_get_try_str(qdict, "qom-type");
> if (!type) {
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] qom-qmp-cmds: fix two memleaks in qmp_object_add
2020-03-09 9:51 ` Igor Mammedov
@ 2020-03-09 10:15 ` Daniel P. Berrangé
2020-03-09 10:22 ` Pan Nengyuan
2020-03-09 10:17 ` Pan Nengyuan
1 sibling, 1 reply; 6+ messages in thread
From: Daniel P. Berrangé @ 2020-03-09 10:15 UTC (permalink / raw)
To: Igor Mammedov
Cc: zhang.zhanghailiang, Pan Nengyuan, qemu-devel, euler.robot,
pbonzini, ehabkost
On Mon, Mar 09, 2020 at 10:51:45AM +0100, Igor Mammedov wrote:
> On Mon, 9 Mar 2020 17:22:12 +0800
> Pan Nengyuan <pannengyuan@huawei.com> wrote:
>
> > 'type/id' forgot to free in qmp_object_add, this patch fix that.
> >
> > The leak stack:
> > Direct leak of 84 byte(s) in 6 object(s) allocated from:
> > #0 0x7fe2a5ebf768 in __interceptor_malloc (/lib64/libasan.so.5+0xef768)
> > #1 0x7fe2a5044445 in g_malloc (/lib64/libglib-2.0.so.0+0x52445)
> > #2 0x7fe2a505dd92 in g_strdup (/lib64/libglib-2.0.so.0+0x6bd92)
> > #3 0x56344954e692 in qmp_object_add /mnt/sdb/qemu-new/qemu_test/qemu/qom/qom-qmp-cmds.c:258
> > #4 0x563449960f5a in do_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:132
> > #5 0x563449960f5a in qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:175
> > #6 0x563449498a30 in monitor_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:145
> > #7 0x56344949a64f in monitor_qmp_bh_dispatcher /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:234
> > #8 0x563449a92a3a in aio_bh_call /mnt/sdb/qemu-new/qemu_test/qemu/util/async.c:136
> >
> > Direct leak of 54 byte(s) in 6 object(s) allocated from:
> > #0 0x7fe2a5ebf768 in __interceptor_malloc (/lib64/libasan.so.5+0xef768)
> > #1 0x7fe2a5044445 in g_malloc (/lib64/libglib-2.0.so.0+0x52445)
> > #2 0x7fe2a505dd92 in g_strdup (/lib64/libglib-2.0.so.0+0x6bd92)
> > #3 0x56344954e6c4 in qmp_object_add /mnt/sdb/qemu-new/qemu_test/qemu/qom/qom-qmp-cmds.c:267
> > #4 0x563449960f5a in do_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:132
> > #5 0x563449960f5a in qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:175
> > #6 0x563449498a30 in monitor_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:145
> > #7 0x56344949a64f in monitor_qmp_bh_dispatcher /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:234
> > #8 0x563449a92a3a in aio_bh_call /mnt/sdb/qemu-new/qemu_test/qemu/util/async.c:136
> >
> > Fixes: 5f07c4d60d091320186e7b0edaf9ed2cc16b2d1e
> > Reported-by: Euler Robot <euler.robot@huawei.com>
> > Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
> > ---
> > qom/qom-qmp-cmds.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/qom/qom-qmp-cmds.c b/qom/qom-qmp-cmds.c
> > index 49db926fcc..ac59ba1aa8 100644
> > --- a/qom/qom-qmp-cmds.c
> > +++ b/qom/qom-qmp-cmds.c
> > @@ -247,8 +247,8 @@ void qmp_object_add(QDict *qdict, QObject **ret_data, Error **errp)
> > QDict *pdict;
> > Visitor *v;
> > Object *obj;
> > - const char *type;
> > - const char *id;
> > + g_autofree const char *type = NULL;
> > + g_autofree const char *id = NULL;
>
> not sure that's it's correct
>
> qdict_get_try_str() returns the reference to a string within
> the QDict, so caller who provided qdict should take care of
> freeing it.
This is correct, but two lines later we have "type = g_strdup(type)".
IOW, the code is storing both a const and non-const string in the
same variable which is gross.
So there's definitely a leak, but this is also not the right way
to fix it.
To fix it, notice that g_strdup says
"Duplicates a string. If str is NULL it returns NULL. The
returned string should be freed with g_free() when no longer
needed."
IOW, instead of
const char *type;
type = qdict_get_try_str(qdict, "qom-type");
if (!type) {
error_setg(errp, QERR_MISSING_PARAMETER, "qom-type");
return;
} else {
type = g_strdup(type);
qdict_del(qdict, "qom-type");
}
we want
g_autofree char *type = NULL;
type = g_strdup(qdict_get_try_str(qdict, "qom-type"));
if (!type) {
error_setg(errp, QERR_MISSING_PARAMETER, "qom-type");
return;
}
qdict_del(qdict, "qom-type");
> > type = qdict_get_try_str(qdict, "qom-type");
> > if (!type) {
Regards,
Daniel
--
|: https://berrange.com -o- https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org -o- https://fstop138.berrange.com :|
|: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] qom-qmp-cmds: fix two memleaks in qmp_object_add
2020-03-09 9:51 ` Igor Mammedov
2020-03-09 10:15 ` Daniel P. Berrangé
@ 2020-03-09 10:17 ` Pan Nengyuan
1 sibling, 0 replies; 6+ messages in thread
From: Pan Nengyuan @ 2020-03-09 10:17 UTC (permalink / raw)
To: Igor Mammedov
Cc: berrange, ehabkost, qemu-devel, euler.robot, pbonzini,
zhang.zhanghailiang
On 3/9/2020 5:51 PM, Igor Mammedov wrote:
> On Mon, 9 Mar 2020 17:22:12 +0800
> Pan Nengyuan <pannengyuan@huawei.com> wrote:
>
>> 'type/id' forgot to free in qmp_object_add, this patch fix that.
>>
>> The leak stack:
>> Direct leak of 84 byte(s) in 6 object(s) allocated from:
>> #0 0x7fe2a5ebf768 in __interceptor_malloc (/lib64/libasan.so.5+0xef768)
>> #1 0x7fe2a5044445 in g_malloc (/lib64/libglib-2.0.so.0+0x52445)
>> #2 0x7fe2a505dd92 in g_strdup (/lib64/libglib-2.0.so.0+0x6bd92)
>> #3 0x56344954e692 in qmp_object_add /mnt/sdb/qemu-new/qemu_test/qemu/qom/qom-qmp-cmds.c:258
>> #4 0x563449960f5a in do_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:132
>> #5 0x563449960f5a in qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:175
>> #6 0x563449498a30 in monitor_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:145
>> #7 0x56344949a64f in monitor_qmp_bh_dispatcher /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:234
>> #8 0x563449a92a3a in aio_bh_call /mnt/sdb/qemu-new/qemu_test/qemu/util/async.c:136
>>
>> Direct leak of 54 byte(s) in 6 object(s) allocated from:
>> #0 0x7fe2a5ebf768 in __interceptor_malloc (/lib64/libasan.so.5+0xef768)
>> #1 0x7fe2a5044445 in g_malloc (/lib64/libglib-2.0.so.0+0x52445)
>> #2 0x7fe2a505dd92 in g_strdup (/lib64/libglib-2.0.so.0+0x6bd92)
>> #3 0x56344954e6c4 in qmp_object_add /mnt/sdb/qemu-new/qemu_test/qemu/qom/qom-qmp-cmds.c:267
>> #4 0x563449960f5a in do_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:132
>> #5 0x563449960f5a in qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:175
>> #6 0x563449498a30 in monitor_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:145
>> #7 0x56344949a64f in monitor_qmp_bh_dispatcher /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:234
>> #8 0x563449a92a3a in aio_bh_call /mnt/sdb/qemu-new/qemu_test/qemu/util/async.c:136
>>
>> Fixes: 5f07c4d60d091320186e7b0edaf9ed2cc16b2d1e
>> Reported-by: Euler Robot <euler.robot@huawei.com>
>> Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
>> ---
>> qom/qom-qmp-cmds.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/qom/qom-qmp-cmds.c b/qom/qom-qmp-cmds.c
>> index 49db926fcc..ac59ba1aa8 100644
>> --- a/qom/qom-qmp-cmds.c
>> +++ b/qom/qom-qmp-cmds.c
>> @@ -247,8 +247,8 @@ void qmp_object_add(QDict *qdict, QObject **ret_data, Error **errp)
>> QDict *pdict;
>> Visitor *v;
>> Object *obj;
>> - const char *type;
>> - const char *id;
>> + g_autofree const char *type = NULL;
>> + g_autofree const char *id = NULL;
>
> not sure that's it's correct
>
> qdict_get_try_str() returns the reference to a string within
> the QDict, so caller who provided qdict should take care of
> freeing it.
>
>>
>> type = qdict_get_try_str(qdict, "qom-type");
>> if (!type) {
>
type = qdict_get_try_str(qdict, "qom-type");
if (!type) {
error_setg(errp, QERR_MISSING_PARAMETER, "qom-type");
return;
} else {
type = g_strdup(type);
qdict_del(qdict, "qom-type");
}
If type is not NULL, it will go to the else branch, type re-assign immediately.
And it's aslo in the scope, so the string within the QDict will not be freed.
> .
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] qom-qmp-cmds: fix two memleaks in qmp_object_add
2020-03-09 10:15 ` Daniel P. Berrangé
@ 2020-03-09 10:22 ` Pan Nengyuan
0 siblings, 0 replies; 6+ messages in thread
From: Pan Nengyuan @ 2020-03-09 10:22 UTC (permalink / raw)
To: Daniel P. Berrangé, Igor Mammedov
Cc: pbonzini, zhang.zhanghailiang, euler.robot, ehabkost, qemu-devel
On 3/9/2020 6:15 PM, Daniel P. Berrangé wrote:
> On Mon, Mar 09, 2020 at 10:51:45AM +0100, Igor Mammedov wrote:
>> On Mon, 9 Mar 2020 17:22:12 +0800
>> Pan Nengyuan <pannengyuan@huawei.com> wrote:
>>
>>> 'type/id' forgot to free in qmp_object_add, this patch fix that.
>>>
>>> The leak stack:
>>> Direct leak of 84 byte(s) in 6 object(s) allocated from:
>>> #0 0x7fe2a5ebf768 in __interceptor_malloc (/lib64/libasan.so.5+0xef768)
>>> #1 0x7fe2a5044445 in g_malloc (/lib64/libglib-2.0.so.0+0x52445)
>>> #2 0x7fe2a505dd92 in g_strdup (/lib64/libglib-2.0.so.0+0x6bd92)
>>> #3 0x56344954e692 in qmp_object_add /mnt/sdb/qemu-new/qemu_test/qemu/qom/qom-qmp-cmds.c:258
>>> #4 0x563449960f5a in do_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:132
>>> #5 0x563449960f5a in qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:175
>>> #6 0x563449498a30 in monitor_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:145
>>> #7 0x56344949a64f in monitor_qmp_bh_dispatcher /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:234
>>> #8 0x563449a92a3a in aio_bh_call /mnt/sdb/qemu-new/qemu_test/qemu/util/async.c:136
>>>
>>> Direct leak of 54 byte(s) in 6 object(s) allocated from:
>>> #0 0x7fe2a5ebf768 in __interceptor_malloc (/lib64/libasan.so.5+0xef768)
>>> #1 0x7fe2a5044445 in g_malloc (/lib64/libglib-2.0.so.0+0x52445)
>>> #2 0x7fe2a505dd92 in g_strdup (/lib64/libglib-2.0.so.0+0x6bd92)
>>> #3 0x56344954e6c4 in qmp_object_add /mnt/sdb/qemu-new/qemu_test/qemu/qom/qom-qmp-cmds.c:267
>>> #4 0x563449960f5a in do_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:132
>>> #5 0x563449960f5a in qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:175
>>> #6 0x563449498a30 in monitor_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:145
>>> #7 0x56344949a64f in monitor_qmp_bh_dispatcher /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:234
>>> #8 0x563449a92a3a in aio_bh_call /mnt/sdb/qemu-new/qemu_test/qemu/util/async.c:136
>>>
>>> Fixes: 5f07c4d60d091320186e7b0edaf9ed2cc16b2d1e
>>> Reported-by: Euler Robot <euler.robot@huawei.com>
>>> Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
>>> ---
>>> qom/qom-qmp-cmds.c | 4 ++--
>>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/qom/qom-qmp-cmds.c b/qom/qom-qmp-cmds.c
>>> index 49db926fcc..ac59ba1aa8 100644
>>> --- a/qom/qom-qmp-cmds.c
>>> +++ b/qom/qom-qmp-cmds.c
>>> @@ -247,8 +247,8 @@ void qmp_object_add(QDict *qdict, QObject **ret_data, Error **errp)
>>> QDict *pdict;
>>> Visitor *v;
>>> Object *obj;
>>> - const char *type;
>>> - const char *id;
>>> + g_autofree const char *type = NULL;
>>> + g_autofree const char *id = NULL;
>>
>> not sure that's it's correct
>>
>> qdict_get_try_str() returns the reference to a string within
>> the QDict, so caller who provided qdict should take care of
>> freeing it.
>
> This is correct, but two lines later we have "type = g_strdup(type)".
>
> IOW, the code is storing both a const and non-const string in the
> same variable which is gross.
>
> So there's definitely a leak, but this is also not the right way
> to fix it.
>
> To fix it, notice that g_strdup says
>
> "Duplicates a string. If str is NULL it returns NULL. The
> returned string should be freed with g_free() when no longer
> needed."
>
> IOW, instead of
>
> const char *type;
>
> type = qdict_get_try_str(qdict, "qom-type");
> if (!type) {
> error_setg(errp, QERR_MISSING_PARAMETER, "qom-type");
> return;
> } else {
> type = g_strdup(type);
> qdict_del(qdict, "qom-type");
> }
>
> we want
>
> g_autofree char *type = NULL;
>
> type = g_strdup(qdict_get_try_str(qdict, "qom-type"));
> if (!type) {
> error_setg(errp, QERR_MISSING_PARAMETER, "qom-type");
> return;
> }
>
> qdict_del(qdict, "qom-type");
Good points. Looks very clear.
Thanks.
>
>>> type = qdict_get_try_str(qdict, "qom-type");
>>> if (!type) {
>
>
>
>
> Regards,
> Daniel
>
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2020-03-09 10:23 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2020-03-09 9:22 [PATCH] qom-qmp-cmds: fix two memleaks in qmp_object_add Pan Nengyuan
2020-03-09 9:51 ` Igor Mammedov
2020-03-09 10:15 ` Daniel P. Berrangé
2020-03-09 10:22 ` Pan Nengyuan
2020-03-09 10:17 ` Pan Nengyuan
2020-03-09 10:06 ` Markus Armbruster
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