* [PATCH] pc: fix leak in pc_system_flash_cleanup_unused
@ 2020-07-01 1:58 Alexander Bulekov
2020-07-01 5:49 ` Paolo Bonzini
2020-07-01 7:34 ` Philippe Mathieu-Daudé
0 siblings, 2 replies; 5+ messages in thread
From: Alexander Bulekov @ 2020-07-01 1:58 UTC (permalink / raw)
To: qemu-devel
Cc: Eduardo Habkost, Michael S. Tsirkin, Alexander Bulekov,
Paolo Bonzini, Richard Henderson
fix a leak detected when building with --enable-sanitizers:
./i386-softmmu/qemu-system-i386
Upon exit:
==13576==ERROR: LeakSanitizer: detected memory leaks
Direct leak of 1216 byte(s) in 1 object(s) allocated from:
#0 0x7f9d2ed5c628 in malloc (/usr/lib/x86_64-linux-gnu/libasan.so.5)
#1 0x7f9d2e963500 in g_malloc (/usr/lib/x86_64-linux-gnu/libglib-2.0.so.)
#2 0x55fa646d25cc in object_new_with_type /tmp/qemu/qom/object.c:686
#3 0x55fa63dbaa88 in qdev_new /tmp/qemu/hw/core/qdev.c:140
#4 0x55fa638a533f in pc_pflash_create /tmp/qemu/hw/i386/pc_sysfw.c:88
#5 0x55fa638a54c4 in pc_system_flash_create /tmp/qemu/hw/i386/pc_sysfw.c:106
#6 0x55fa646caa1d in object_init_with_type /tmp/qemu/qom/object.c:369
#7 0x55fa646d20b5 in object_initialize_with_type /tmp/qemu/qom/object.c:511
#8 0x55fa646d2606 in object_new_with_type /tmp/qemu/qom/object.c:687
#9 0x55fa639431e9 in qemu_init /tmp/qemu/softmmu/vl.c:3878
#10 0x55fa6335c1b8 in main /tmp/qemu/softmmu/main.c:48
#11 0x7f9d2cf06e0a in __libc_start_main ../csu/libc-start.c:308
#12 0x55fa6335f8e9 in _start (/tmp/qemu/build/i386-softmmu/qemu-system-i386)
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
---
I am not very familiar with the QOM, so maybe this isn't the right way
of going about this. With the call to object_property_add_child in
pc_sysfw.c:pc_pflash_create, object_ref is called on the pflash device.
In the pc_system_flash_cleanup_unused function, there are calls to
object_propery_del and object_unparent, but it seems neither of these
calls object_unref. So do we need to manually decrement the refcount?
hw/i386/pc_sysfw.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
index ec2a3b3e7e..f69a93671a 100644
--- a/hw/i386/pc_sysfw.c
+++ b/hw/i386/pc_sysfw.c
@@ -123,6 +123,7 @@ static void pc_system_flash_cleanup_unused(PCMachineState *pcms)
object_property_del(OBJECT(pcms), prop_name);
g_free(prop_name);
object_unparent(dev_obj);
+ object_unref(dev_obj);
pcms->flash[i] = NULL;
}
}
--
2.26.2
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] pc: fix leak in pc_system_flash_cleanup_unused
2020-07-01 1:58 [PATCH] pc: fix leak in pc_system_flash_cleanup_unused Alexander Bulekov
@ 2020-07-01 5:49 ` Paolo Bonzini
2020-07-01 13:06 ` Alexander Bulekov
2020-07-01 7:34 ` Philippe Mathieu-Daudé
1 sibling, 1 reply; 5+ messages in thread
From: Paolo Bonzini @ 2020-07-01 5:49 UTC (permalink / raw)
To: Alexander Bulekov, qemu-devel
Cc: Michael S. Tsirkin, Eduardo Habkost, Richard Henderson
On 01/07/20 03:58, Alexander Bulekov wrote:
> fix a leak detected when building with --enable-sanitizers:
> ./i386-softmmu/qemu-system-i386
> Upon exit:
> ==13576==ERROR: LeakSanitizer: detected memory leaks
>
> Direct leak of 1216 byte(s) in 1 object(s) allocated from:
> #0 0x7f9d2ed5c628 in malloc (/usr/lib/x86_64-linux-gnu/libasan.so.5)
> #1 0x7f9d2e963500 in g_malloc (/usr/lib/x86_64-linux-gnu/libglib-2.0.so.)
> #2 0x55fa646d25cc in object_new_with_type /tmp/qemu/qom/object.c:686
> #3 0x55fa63dbaa88 in qdev_new /tmp/qemu/hw/core/qdev.c:140
> #4 0x55fa638a533f in pc_pflash_create /tmp/qemu/hw/i386/pc_sysfw.c:88
> #5 0x55fa638a54c4 in pc_system_flash_create /tmp/qemu/hw/i386/pc_sysfw.c:106
> #6 0x55fa646caa1d in object_init_with_type /tmp/qemu/qom/object.c:369
> #7 0x55fa646d20b5 in object_initialize_with_type /tmp/qemu/qom/object.c:511
> #8 0x55fa646d2606 in object_new_with_type /tmp/qemu/qom/object.c:687
> #9 0x55fa639431e9 in qemu_init /tmp/qemu/softmmu/vl.c:3878
> #10 0x55fa6335c1b8 in main /tmp/qemu/softmmu/main.c:48
> #11 0x7f9d2cf06e0a in __libc_start_main ../csu/libc-start.c:308
> #12 0x55fa6335f8e9 in _start (/tmp/qemu/build/i386-softmmu/qemu-system-i386)
>
> Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
> ---
>
> I am not very familiar with the QOM, so maybe this isn't the right way
> of going about this. With the call to object_property_add_child in
> pc_sysfw.c:pc_pflash_create, object_ref is called on the pflash device.
> In the pc_system_flash_cleanup_unused function, there are calls to
> object_propery_del and object_unparent, but it seems neither of these
> calls object_unref. So do we need to manually decrement the refcount?
Yes; you can also add it in pc_pflash_create, because
/*
* Since object_property_add_child added a reference to the child object,
* we can drop the reference added by object_initialize(), so the child
* property will own the only reference to the object.
*/
(from object_initialize_childv).
Paolo
> hw/i386/pc_sysfw.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
> index ec2a3b3e7e..f69a93671a 100644
> --- a/hw/i386/pc_sysfw.c
> +++ b/hw/i386/pc_sysfw.c
> @@ -123,6 +123,7 @@ static void pc_system_flash_cleanup_unused(PCMachineState *pcms)
> object_property_del(OBJECT(pcms), prop_name);
> g_free(prop_name);
> object_unparent(dev_obj);
> + object_unref(dev_obj);
> pcms->flash[i] = NULL;
> }
> }
>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] pc: fix leak in pc_system_flash_cleanup_unused
2020-07-01 5:49 ` Paolo Bonzini
@ 2020-07-01 13:06 ` Alexander Bulekov
2020-07-01 14:18 ` Paolo Bonzini
0 siblings, 1 reply; 5+ messages in thread
From: Alexander Bulekov @ 2020-07-01 13:06 UTC (permalink / raw)
To: Paolo Bonzini
Cc: Michael S. Tsirkin, qemu-devel, Eduardo Habkost, Richard Henderson
On 200701 0749, Paolo Bonzini wrote:
> On 01/07/20 03:58, Alexander Bulekov wrote:
> > fix a leak detected when building with --enable-sanitizers:
> > ./i386-softmmu/qemu-system-i386
> > Upon exit:
> > ==13576==ERROR: LeakSanitizer: detected memory leaks
> >
> > Direct leak of 1216 byte(s) in 1 object(s) allocated from:
> > #0 0x7f9d2ed5c628 in malloc (/usr/lib/x86_64-linux-gnu/libasan.so.5)
> > #1 0x7f9d2e963500 in g_malloc (/usr/lib/x86_64-linux-gnu/libglib-2.0.so.)
> > #2 0x55fa646d25cc in object_new_with_type /tmp/qemu/qom/object.c:686
> > #3 0x55fa63dbaa88 in qdev_new /tmp/qemu/hw/core/qdev.c:140
> > #4 0x55fa638a533f in pc_pflash_create /tmp/qemu/hw/i386/pc_sysfw.c:88
> > #5 0x55fa638a54c4 in pc_system_flash_create /tmp/qemu/hw/i386/pc_sysfw.c:106
> > #6 0x55fa646caa1d in object_init_with_type /tmp/qemu/qom/object.c:369
> > #7 0x55fa646d20b5 in object_initialize_with_type /tmp/qemu/qom/object.c:511
> > #8 0x55fa646d2606 in object_new_with_type /tmp/qemu/qom/object.c:687
> > #9 0x55fa639431e9 in qemu_init /tmp/qemu/softmmu/vl.c:3878
> > #10 0x55fa6335c1b8 in main /tmp/qemu/softmmu/main.c:48
> > #11 0x7f9d2cf06e0a in __libc_start_main ../csu/libc-start.c:308
> > #12 0x55fa6335f8e9 in _start (/tmp/qemu/build/i386-softmmu/qemu-system-i386)
> >
> > Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
> > ---
> >
> > I am not very familiar with the QOM, so maybe this isn't the right way
> > of going about this. With the call to object_property_add_child in
> > pc_sysfw.c:pc_pflash_create, object_ref is called on the pflash device.
> > In the pc_system_flash_cleanup_unused function, there are calls to
> > object_propery_del and object_unparent, but it seems neither of these
> > calls object_unref. So do we need to manually decrement the refcount?
>
> Yes; you can also add it in pc_pflash_create, because
>
> /*
> * Since object_property_add_child added a reference to the child object,
> * we can drop the reference added by object_initialize(), so the child
> * property will own the only reference to the object.
> */
>
> (from object_initialize_childv).
Isn't that reference used at pc_sysfw.c:104 ?
pcms->flash[0] = pc_pflash_create(pcms, "system.flash0", "pflash0");
In this case, shouldn't we unref when
pc_sysfw.c:126 pcms->flash[0] = NULL
?
-Alex
> Paolo
>
> > hw/i386/pc_sysfw.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
> > index ec2a3b3e7e..f69a93671a 100644
> > --- a/hw/i386/pc_sysfw.c
> > +++ b/hw/i386/pc_sysfw.c
> > @@ -123,6 +123,7 @@ static void pc_system_flash_cleanup_unused(PCMachineState *pcms)
> > object_property_del(OBJECT(pcms), prop_name);
> > g_free(prop_name);
> > object_unparent(dev_obj);
> > + object_unref(dev_obj);
> > pcms->flash[i] = NULL;
> > }
> > }
> >
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] pc: fix leak in pc_system_flash_cleanup_unused
2020-07-01 13:06 ` Alexander Bulekov
@ 2020-07-01 14:18 ` Paolo Bonzini
0 siblings, 0 replies; 5+ messages in thread
From: Paolo Bonzini @ 2020-07-01 14:18 UTC (permalink / raw)
To: Alexander Bulekov
Cc: Michael S. Tsirkin, qemu-devel, Eduardo Habkost, Richard Henderson
On 01/07/20 15:06, Alexander Bulekov wrote:
>> Yes; you can also add it in pc_pflash_create, because
>>
>> /*
>> * Since object_property_add_child added a reference to the child object,
>> * we can drop the reference added by object_initialize(), so the child
>> * property will own the only reference to the object.
>> */
>>
>> (from object_initialize_childv).
> Isn't that reference used at pc_sysfw.c:104 ?
> pcms->flash[0] = pc_pflash_create(pcms, "system.flash0", "pflash0");
>
> In this case, shouldn't we unref when
> pc_sysfw.c:126 pcms->flash[0] = NULL
> ?
object_unparent already drops a reference. Therefore, it's okay to drop
the reference immediately after object_property_add_child (which adds a
reference) and match pc_pflash_create with just object_unparent.
Paolo
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] pc: fix leak in pc_system_flash_cleanup_unused
2020-07-01 1:58 [PATCH] pc: fix leak in pc_system_flash_cleanup_unused Alexander Bulekov
2020-07-01 5:49 ` Paolo Bonzini
@ 2020-07-01 7:34 ` Philippe Mathieu-Daudé
1 sibling, 0 replies; 5+ messages in thread
From: Philippe Mathieu-Daudé @ 2020-07-01 7:34 UTC (permalink / raw)
To: Alexander Bulekov, qemu-devel
Cc: Paolo Bonzini, Richard Henderson, Eduardo Habkost,
Markus Armbruster, Michael S. Tsirkin
On 7/1/20 3:58 AM, Alexander Bulekov wrote:
> fix a leak detected when building with --enable-sanitizers:
> ./i386-softmmu/qemu-system-i386
> Upon exit:
> ==13576==ERROR: LeakSanitizer: detected memory leaks
>
> Direct leak of 1216 byte(s) in 1 object(s) allocated from:
> #0 0x7f9d2ed5c628 in malloc (/usr/lib/x86_64-linux-gnu/libasan.so.5)
> #1 0x7f9d2e963500 in g_malloc (/usr/lib/x86_64-linux-gnu/libglib-2.0.so.)
> #2 0x55fa646d25cc in object_new_with_type /tmp/qemu/qom/object.c:686
> #3 0x55fa63dbaa88 in qdev_new /tmp/qemu/hw/core/qdev.c:140
> #4 0x55fa638a533f in pc_pflash_create /tmp/qemu/hw/i386/pc_sysfw.c:88
> #5 0x55fa638a54c4 in pc_system_flash_create /tmp/qemu/hw/i386/pc_sysfw.c:106
> #6 0x55fa646caa1d in object_init_with_type /tmp/qemu/qom/object.c:369
> #7 0x55fa646d20b5 in object_initialize_with_type /tmp/qemu/qom/object.c:511
> #8 0x55fa646d2606 in object_new_with_type /tmp/qemu/qom/object.c:687
> #9 0x55fa639431e9 in qemu_init /tmp/qemu/softmmu/vl.c:3878
> #10 0x55fa6335c1b8 in main /tmp/qemu/softmmu/main.c:48
> #11 0x7f9d2cf06e0a in __libc_start_main ../csu/libc-start.c:308
> #12 0x55fa6335f8e9 in _start (/tmp/qemu/build/i386-softmmu/qemu-system-i386)
>
> Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
> ---
>
> I am not very familiar with the QOM, so maybe this isn't the right way
> of going about this. With the call to object_property_add_child in
> pc_sysfw.c:pc_pflash_create, object_ref is called on the pflash device.
> In the pc_system_flash_cleanup_unused function, there are calls to
> object_propery_del and object_unparent, but it seems neither of these
> calls object_unref. So do we need to manually decrement the refcount?
Hint in such case, look at who wrote the commit, and Cc the author
to get an explanation:
$ git blame hw/i386/pc_sysfw.c
ebc29e1beab hw/i386/pc_sysfw.c (Markus Armbruster 2019-03-11
18:39:26 +0100 119) for (i = 0; i < ARRAY_SIZE(pcms->flash); i++) {
ebc29e1beab hw/i386/pc_sysfw.c (Markus Armbruster 2019-03-11
18:39:26 +0100 120) dev_obj = OBJECT(pcms->flash[i]);
ebc29e1beab hw/i386/pc_sysfw.c (Markus Armbruster 2019-03-11
18:39:26 +0100 121) if (!object_property_get_bool(dev_obj,
"realized", &error_abort)) {
ebc29e1beab hw/i386/pc_sysfw.c (Markus Armbruster 2019-03-11
18:39:26 +0100 122) prop_name = g_strdup_printf("pflash%d", i);
df4fe0b291b hw/i386/pc_sysfw.c (Markus Armbruster 2020-05-05
17:29:26 +0200 123) object_property_del(OBJECT(pcms),
prop_name);
ebc29e1beab hw/i386/pc_sysfw.c (Markus Armbruster 2019-03-11
18:39:26 +0100 124) g_free(prop_name);
ebc29e1beab hw/i386/pc_sysfw.c (Markus Armbruster 2019-03-11
18:39:26 +0100 125) object_unparent(dev_obj);
ebc29e1beab hw/i386/pc_sysfw.c (Markus Armbruster 2019-03-11
18:39:26 +0100 126) pcms->flash[i] = NULL;
ebc29e1beab hw/i386/pc_sysfw.c (Markus Armbruster 2019-03-11
18:39:26 +0100 127) }
ebc29e1beab hw/i386/pc_sysfw.c (Markus Armbruster 2019-03-11
18:39:26 +0100 128) }
>
> hw/i386/pc_sysfw.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/hw/i386/pc_sysfw.c b/hw/i386/pc_sysfw.c
> index ec2a3b3e7e..f69a93671a 100644
> --- a/hw/i386/pc_sysfw.c
> +++ b/hw/i386/pc_sysfw.c
> @@ -123,6 +123,7 @@ static void pc_system_flash_cleanup_unused(PCMachineState *pcms)
> object_property_del(OBJECT(pcms), prop_name);
> g_free(prop_name);
> object_unparent(dev_obj);
> + object_unref(dev_obj);
> pcms->flash[i] = NULL;
> }
> }
>
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2020-07-01 14:31 UTC | newest]
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2020-07-01 1:58 [PATCH] pc: fix leak in pc_system_flash_cleanup_unused Alexander Bulekov
2020-07-01 5:49 ` Paolo Bonzini
2020-07-01 13:06 ` Alexander Bulekov
2020-07-01 14:18 ` Paolo Bonzini
2020-07-01 7:34 ` Philippe Mathieu-Daudé
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