[PATCH] hmp: fix memory leak in qom_composition_compare()

[PATCH] hmp: fix memory leak in qom_composition_compare()

[Li Qiang]

While 'make chekc', I got following error:

root@ubuntu:~/qemu# ./tests/qtest/device-introspect-test
/x86_64/device/introspect/list: OK
/x86_64/device/introspect/list-fields: OK
/x86_64/device/introspect/none:
=================================================================
==53741==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 212 byte(s) in 20 object(s) allocated from:
    #0 0x7f3b6319cb40 in __interceptor_malloc (/usr/lib/x86_64-linux-gnu/libasan.so.4+0xdeb40)
    #1 0x7f3b62805ab8 in g_malloc (/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x51ab8)

SUMMARY: AddressSanitizer: 212 byte(s) leaked in 20 allocation(s).
tests/qtest/libqtest.c:166: kill_qemu() tried to terminate QEMU process but encountered exit status 1 (expected 0)
Aborted (core dumped)

This is because the 'info qom-tree' path has a memory leak and qemu
exit 1. The leak is in 'qom_composition_compare'. This patch fixes this.

Fixes: e8c9e65816f("qom: Make "info qom-tree" show children sorted")
Signed-off-by: Li Qiang <liq3ea@163.com>
---
 qom/qom-hmp-cmds.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/qom/qom-hmp-cmds.c b/qom/qom-hmp-cmds.c
index 9ed8bb1c9f..3547d5ba4e 100644
--- a/qom/qom-hmp-cmds.c
+++ b/qom/qom-hmp-cmds.c
@@ -96,8 +96,10 @@ static void print_qom_composition(Monitor *mon, Object *obj, int indent);
 
 static int qom_composition_compare(const void *a, const void *b, void *ignore)
 {
-    return g_strcmp0(a ? object_get_canonical_path_component(a) : NULL,
-                     b ? object_get_canonical_path_component(b) : NULL);
+    g_autofree char *t1 = a ? object_get_canonical_path_component(a) : NULL;
+    g_autofree char *t2 = b ? object_get_canonical_path_component(b) : NULL;
+
+    return g_strcmp0(t1, t2);
 }
 
 static int insert_qom_composition_child(Object *obj, void *opaque)
-- 
2.17.1

Re: [PATCH] hmp: fix memory leak in qom_composition_compare()

[Philippe Mathieu-Daudé]

On 7/14/20 5:11 PM, Li Qiang wrote:
> While 'make chekc', I got following error:
> 
> root@ubuntu:~/qemu# ./tests/qtest/device-introspect-test
> /x86_64/device/introspect/list: OK
> /x86_64/device/introspect/list-fields: OK
> /x86_64/device/introspect/none:
> =================================================================
> ==53741==ERROR: LeakSanitizer: detected memory leaks
> 
> Direct leak of 212 byte(s) in 20 object(s) allocated from:
>     #0 0x7f3b6319cb40 in __interceptor_malloc (/usr/lib/x86_64-linux-gnu/libasan.so.4+0xdeb40)
>     #1 0x7f3b62805ab8 in g_malloc (/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x51ab8)
> 
> SUMMARY: AddressSanitizer: 212 byte(s) leaked in 20 allocation(s).
> tests/qtest/libqtest.c:166: kill_qemu() tried to terminate QEMU process but encountered exit status 1 (expected 0)
> Aborted (core dumped)
> 
> This is because the 'info qom-tree' path has a memory leak and qemu
> exit 1. The leak is in 'qom_composition_compare'. This patch fixes this.
> 
> Fixes: e8c9e65816f("qom: Make "info qom-tree" show children sorted")
> Signed-off-by: Li Qiang <liq3ea@163.com>
> ---
>  qom/qom-hmp-cmds.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/qom/qom-hmp-cmds.c b/qom/qom-hmp-cmds.c
> index 9ed8bb1c9f..3547d5ba4e 100644
> --- a/qom/qom-hmp-cmds.c
> +++ b/qom/qom-hmp-cmds.c
> @@ -96,8 +96,10 @@ static void print_qom_composition(Monitor *mon, Object *obj, int indent);
>  
>  static int qom_composition_compare(const void *a, const void *b, void *ignore)
>  {
> -    return g_strcmp0(a ? object_get_canonical_path_component(a) : NULL,
> -                     b ? object_get_canonical_path_component(b) : NULL);
> +    g_autofree char *t1 = a ? object_get_canonical_path_component(a) : NULL;
> +    g_autofree char *t2 = b ? object_get_canonical_path_component(b) : NULL;
> +
> +    return g_strcmp0(t1, t2);
>  }
>  
>  static int insert_qom_composition_child(Object *obj, void *opaque)
> 

Ah you won the race with Markus:
https://lists.gnu.org/archive/html/qemu-devel/2020-07/msg04740.html

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

Re: [PATCH] hmp: fix memory leak in qom_composition_compare()

[Li Qiang]

Philippe Mathieu-Daudé <philmd@redhat.com> 于2020年7月15日周三 上午12:47写道：
>
> On 7/14/20 5:11 PM, Li Qiang wrote:
> > While 'make chekc', I got following error:
> >
> > root@ubuntu:~/qemu# ./tests/qtest/device-introspect-test
> > /x86_64/device/introspect/list: OK
> > /x86_64/device/introspect/list-fields: OK
> > /x86_64/device/introspect/none:
> > =================================================================
> > ==53741==ERROR: LeakSanitizer: detected memory leaks
> >
> > Direct leak of 212 byte(s) in 20 object(s) allocated from:
> >     #0 0x7f3b6319cb40 in __interceptor_malloc (/usr/lib/x86_64-linux-gnu/libasan.so.4+0xdeb40)
> >     #1 0x7f3b62805ab8 in g_malloc (/usr/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x51ab8)
> >
> > SUMMARY: AddressSanitizer: 212 byte(s) leaked in 20 allocation(s).
> > tests/qtest/libqtest.c:166: kill_qemu() tried to terminate QEMU process but encountered exit status 1 (expected 0)
> > Aborted (core dumped)
> >
> > This is because the 'info qom-tree' path has a memory leak and qemu
> > exit 1. The leak is in 'qom_composition_compare'. This patch fixes this.
> >
> > Fixes: e8c9e65816f("qom: Make "info qom-tree" show children sorted")
> > Signed-off-by: Li Qiang <liq3ea@163.com>
> > ---
> >  qom/qom-hmp-cmds.c | 6 ++++--
> >  1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/qom/qom-hmp-cmds.c b/qom/qom-hmp-cmds.c
> > index 9ed8bb1c9f..3547d5ba4e 100644
> > --- a/qom/qom-hmp-cmds.c
> > +++ b/qom/qom-hmp-cmds.c
> > @@ -96,8 +96,10 @@ static void print_qom_composition(Monitor *mon, Object *obj, int indent);
> >
> >  static int qom_composition_compare(const void *a, const void *b, void *ignore)
> >  {
> > -    return g_strcmp0(a ? object_get_canonical_path_component(a) : NULL,
> > -                     b ? object_get_canonical_path_component(b) : NULL);
> > +    g_autofree char *t1 = a ? object_get_canonical_path_component(a) : NULL;
> > +    g_autofree char *t2 = b ? object_get_canonical_path_component(b) : NULL;
> > +
> > +    return g_strcmp0(t1, t2);
> >  }
> >
> >  static int insert_qom_composition_child(Object *obj, void *opaque)
> >
>
> Ah you won the race with Markus:
> https://lists.gnu.org/archive/html/qemu-devel/2020-07/msg04740.html
>

Oh interesting, I just want to  begin to write the e1000e tx bh
discussed with Jason.
But found there are some memleak issue.

> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>