[PATCH] PM: Fix memory leak in pm_vt_switch_unregister().

[PATCH] PM: Fix memory leak in pm_vt_switch_unregister().

[Masami Ichikawa]

kmemleak reported a memory leak as below.

unreferenced object 0xffff880118f14700 (size 32):
  comm "swapper/0", pid 1, jiffies 4294877401 (age 123.283s)
  hex dump (first 32 bytes):
    00 01 10 00 00 00 ad de 00 02 20 00 00 00 ad de  .......... .....
    00 d4 d2 18 01 88 ff ff 01 00 00 00 00 04 00 00  ................
  backtrace:
    [<ffffffff814edb1e>] kmemleak_alloc+0x4e/0xb0
    [<ffffffff811889dc>] kmem_cache_alloc_trace+0x1ec/0x260
    [<ffffffff810aba66>] pm_vt_switch_required+0x76/0xb0
    [<ffffffff812f39f5>] register_framebuffer+0x195/0x320
    [<ffffffff8130af18>] efifb_probe+0x718/0x780
    [<ffffffff81391495>] platform_drv_probe+0x45/0xb0
    [<ffffffff8138f407>] driver_probe_device+0x87/0x3a0
    [<ffffffff8138f7f3>] __driver_attach+0x93/0xa0
    [<ffffffff8138d413>] bus_for_each_dev+0x63/0xa0
    [<ffffffff8138ee5e>] driver_attach+0x1e/0x20
    [<ffffffff8138ea40>] bus_add_driver+0x180/0x250
    [<ffffffff8138fe74>] driver_register+0x64/0xf0
    [<ffffffff813913ba>] __platform_driver_register+0x4a/0x50
    [<ffffffff8191e028>] efifb_driver_init+0x12/0x14
    [<ffffffff8100214a>] do_one_initcall+0xfa/0x1b0
    [<ffffffff818e40e0>] kernel_init_freeable+0x17b/0x201

In pm_vt_switch_required(), "entry" variable is allocated via kmalloc().
So, in pm_vt_switch_unregister(), it needs to call kfree() when object
is deleted from list.

Signed-off-by: Masami Ichikawa <masami256@gmail.com>
---
 kernel/power/console.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/power/console.c b/kernel/power/console.c
index 463aa673..eacb8bd 100644
--- a/kernel/power/console.c
+++ b/kernel/power/console.c
@@ -81,6 +81,7 @@ void pm_vt_switch_unregister(struct device *dev)
 	list_for_each_entry(tmp, &pm_vt_switch_list, head) {
 		if (tmp->dev == dev) {
 			list_del(&tmp->head);
+			kfree(tmp);
 			break;
 		}
 	}
-- 
1.8.4.2

Re: [PATCH] PM: Fix memory leak in pm_vt_switch_unregister().

[Pavel Machek]

On Thu 2013-12-19 20:00:47, Masami Ichikawa wrote:
> kmemleak reported a memory leak as below.
> 
> unreferenced object 0xffff880118f14700 (size 32):
>   comm "swapper/0", pid 1, jiffies 4294877401 (age 123.283s)
>   hex dump (first 32 bytes):
>     00 01 10 00 00 00 ad de 00 02 20 00 00 00 ad de  .......... .....
>     00 d4 d2 18 01 88 ff ff 01 00 00 00 00 04 00 00  ................
>   backtrace:
>     [<ffffffff814edb1e>] kmemleak_alloc+0x4e/0xb0
>     [<ffffffff811889dc>] kmem_cache_alloc_trace+0x1ec/0x260
>     [<ffffffff810aba66>] pm_vt_switch_required+0x76/0xb0
>     [<ffffffff812f39f5>] register_framebuffer+0x195/0x320
>     [<ffffffff8130af18>] efifb_probe+0x718/0x780
>     [<ffffffff81391495>] platform_drv_probe+0x45/0xb0
>     [<ffffffff8138f407>] driver_probe_device+0x87/0x3a0
>     [<ffffffff8138f7f3>] __driver_attach+0x93/0xa0
>     [<ffffffff8138d413>] bus_for_each_dev+0x63/0xa0
>     [<ffffffff8138ee5e>] driver_attach+0x1e/0x20
>     [<ffffffff8138ea40>] bus_add_driver+0x180/0x250
>     [<ffffffff8138fe74>] driver_register+0x64/0xf0
>     [<ffffffff813913ba>] __platform_driver_register+0x4a/0x50
>     [<ffffffff8191e028>] efifb_driver_init+0x12/0x14
>     [<ffffffff8100214a>] do_one_initcall+0xfa/0x1b0
>     [<ffffffff818e40e0>] kernel_init_freeable+0x17b/0x201
> 
> In pm_vt_switch_required(), "entry" variable is allocated via kmalloc().
> So, in pm_vt_switch_unregister(), it needs to call kfree() when object
> is deleted from list.
> 
> Signed-off-by: Masami Ichikawa <masami256@gmail.com>

Reviewed-by: Pavel Machek <pavel@ucw.cz>

Thanks!

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: [PATCH] PM: Fix memory leak in pm_vt_switch_unregister().

[Rafael J. Wysocki]

On Thursday, December 19, 2013 01:42:28 PM Pavel Machek wrote:
> On Thu 2013-12-19 20:00:47, Masami Ichikawa wrote:
> > kmemleak reported a memory leak as below.
> > 
> > unreferenced object 0xffff880118f14700 (size 32):
> >   comm "swapper/0", pid 1, jiffies 4294877401 (age 123.283s)
> >   hex dump (first 32 bytes):
> >     00 01 10 00 00 00 ad de 00 02 20 00 00 00 ad de  .......... .....
> >     00 d4 d2 18 01 88 ff ff 01 00 00 00 00 04 00 00  ................
> >   backtrace:
> >     [<ffffffff814edb1e>] kmemleak_alloc+0x4e/0xb0
> >     [<ffffffff811889dc>] kmem_cache_alloc_trace+0x1ec/0x260
> >     [<ffffffff810aba66>] pm_vt_switch_required+0x76/0xb0
> >     [<ffffffff812f39f5>] register_framebuffer+0x195/0x320
> >     [<ffffffff8130af18>] efifb_probe+0x718/0x780
> >     [<ffffffff81391495>] platform_drv_probe+0x45/0xb0
> >     [<ffffffff8138f407>] driver_probe_device+0x87/0x3a0
> >     [<ffffffff8138f7f3>] __driver_attach+0x93/0xa0
> >     [<ffffffff8138d413>] bus_for_each_dev+0x63/0xa0
> >     [<ffffffff8138ee5e>] driver_attach+0x1e/0x20
> >     [<ffffffff8138ea40>] bus_add_driver+0x180/0x250
> >     [<ffffffff8138fe74>] driver_register+0x64/0xf0
> >     [<ffffffff813913ba>] __platform_driver_register+0x4a/0x50
> >     [<ffffffff8191e028>] efifb_driver_init+0x12/0x14
> >     [<ffffffff8100214a>] do_one_initcall+0xfa/0x1b0
> >     [<ffffffff818e40e0>] kernel_init_freeable+0x17b/0x201
> > 
> > In pm_vt_switch_required(), "entry" variable is allocated via kmalloc().
> > So, in pm_vt_switch_unregister(), it needs to call kfree() when object
> > is deleted from list.
> > 
> > Signed-off-by: Masami Ichikawa <masami256@gmail.com>
> 
> Reviewed-by: Pavel Machek <pavel@ucw.cz>

Applied and queued up for the next PM pull request.

Thanks!

-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.