[Qemu-devel] [PATCH] vl.c: Fix memory leak in qemu_register_machine

[Qemu-devel] [PATCH] vl.c: Fix memory leak in qemu_register_machine

[Christian Borntraeger]

since commit 261747f176f6 (vl: Use MachineClass instead of global
QEMUMachine list) valgrind complains about the following:

==54082== 57 bytes in 3 blocks are definitely lost in loss record 365 of 729
==54082==    at 0x4031AFE: malloc (vg_replace_malloc.c:292)
==54082==    by 0x4145569: g_malloc (in /usr/lib64/libglib-2.0.so.0.3400.2)
==54082==    by 0x415F9E9: g_strconcat (in /usr/lib64/libglib-2.0.so.0.3400.2)
==54082==    by 0x80157FE7: qemu_register_machine (vl.c:1597)
==54082==    by 0x80208E6B: module_call_init (module.c:105)
==54082==    by 0x80013B91: main (vl.c:3000)

Turns out that valgrind is right. We simply forget the memory that
g_strconcat has allocated. Lets free it after the type_register.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
---
 vl.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/vl.c b/vl.c
index b363a21..97290c9 100644
--- a/vl.c
+++ b/vl.c
@@ -1592,6 +1592,7 @@ int qemu_register_machine(QEMUMachine *m)
     };
 
     type_register(&ti);
+    g_free((void *) ti.name);
 
     return 0;
 }
-- 
1.8.4.2

Re: [Qemu-devel] [PATCH] vl.c: Fix memory leak in qemu_register_machine

[Marcel Apfelbaum]

On Mon, 2014-03-17 at 22:53 +0100, Christian Borntraeger wrote:
> since commit 261747f176f6 (vl: Use MachineClass instead of global
> QEMUMachine list) valgrind complains about the following:
> 
> ==54082== 57 bytes in 3 blocks are definitely lost in loss record 365 of 729
> ==54082==    at 0x4031AFE: malloc (vg_replace_malloc.c:292)
> ==54082==    by 0x4145569: g_malloc (in /usr/lib64/libglib-2.0.so.0.3400.2)
> ==54082==    by 0x415F9E9: g_strconcat (in /usr/lib64/libglib-2.0.so.0.3400.2)
> ==54082==    by 0x80157FE7: qemu_register_machine (vl.c:1597)
> ==54082==    by 0x80208E6B: module_call_init (module.c:105)
> ==54082==    by 0x80013B91: main (vl.c:3000)
> 
> Turns out that valgrind is right. We simply forget the memory that
> g_strconcat has allocated. Lets free it after the type_register.
> 
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
> ---
>  vl.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/vl.c b/vl.c
> index b363a21..97290c9 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -1592,6 +1592,7 @@ int qemu_register_machine(QEMUMachine *m)
>      };
>  
>      type_register(&ti);
> +    g_free((void *) ti.name);
I would remove the   ^  space here, but maybe Andreas can remove it when he applies it.
Thanks again!

Reviewed-by: Marcel Apfelbaum <marcel.a@redhat.com>

>  
>      return 0;
>  }

Re: [Qemu-devel] [PATCH] vl.c: Fix memory leak in qemu_register_machine

[Markus Armbruster]

Marcel Apfelbaum <marcel.a@redhat.com> writes:

> On Mon, 2014-03-17 at 22:53 +0100, Christian Borntraeger wrote:
>> since commit 261747f176f6 (vl: Use MachineClass instead of global
>> QEMUMachine list) valgrind complains about the following:
>> 
>> ==54082== 57 bytes in 3 blocks are definitely lost in loss record 365 of 729
>> ==54082==    at 0x4031AFE: malloc (vg_replace_malloc.c:292)
>> ==54082==    by 0x4145569: g_malloc (in /usr/lib64/libglib-2.0.so.0.3400.2)
>> ==54082==    by 0x415F9E9: g_strconcat (in /usr/lib64/libglib-2.0.so.0.3400.2)
>> ==54082==    by 0x80157FE7: qemu_register_machine (vl.c:1597)
>> ==54082==    by 0x80208E6B: module_call_init (module.c:105)
>> ==54082==    by 0x80013B91: main (vl.c:3000)
>> 
>> Turns out that valgrind is right. We simply forget the memory that
>> g_strconcat has allocated. Lets free it after the type_register.
>> 
>> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
>> ---
>>  vl.c | 1 +
>>  1 file changed, 1 insertion(+)
>> 
>> diff --git a/vl.c b/vl.c
>> index b363a21..97290c9 100644
>> --- a/vl.c
>> +++ b/vl.c
>> @@ -1592,6 +1592,7 @@ int qemu_register_machine(QEMUMachine *m)
>>      };
>>  
>>      type_register(&ti);
>> +    g_free((void *) ti.name);
> I would remove the ^ space here, but maybe Andreas can remove it when
> he applies it.

To be precise: no space between cast and its operand: (void *)ti.name

[...]

Re: [Qemu-devel] [PATCH] vl.c: Fix memory leak in qemu_register_machine

[Michael S. Tsirkin]

On Mon, Mar 17, 2014 at 10:53:25PM +0100, Christian Borntraeger wrote:
> since commit 261747f176f6 (vl: Use MachineClass instead of global
> QEMUMachine list) valgrind complains about the following:
> 
> ==54082== 57 bytes in 3 blocks are definitely lost in loss record 365 of 729
> ==54082==    at 0x4031AFE: malloc (vg_replace_malloc.c:292)
> ==54082==    by 0x4145569: g_malloc (in /usr/lib64/libglib-2.0.so.0.3400.2)
> ==54082==    by 0x415F9E9: g_strconcat (in /usr/lib64/libglib-2.0.so.0.3400.2)
> ==54082==    by 0x80157FE7: qemu_register_machine (vl.c:1597)
> ==54082==    by 0x80208E6B: module_call_init (module.c:105)
> ==54082==    by 0x80013B91: main (vl.c:3000)
> 
> Turns out that valgrind is right. We simply forget the memory that
> g_strconcat has allocated. Lets free it after the type_register.
> 
> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
> ---
>  vl.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/vl.c b/vl.c
> index b363a21..97290c9 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -1592,6 +1592,7 @@ int qemu_register_machine(QEMUMachine *m)
>      };
>  
>      type_register(&ti);
> +    g_free((void *) ti.name);
>  
>      return 0;
>  }

I think it's best to avoid casting away constness.
How about keeping a copy of name and freeing that?

> -- 
> 1.8.4.2