Re: [PATCH] fbcon: Fix memory leak in con2fb_release_oldinfo()

From: Tomi Valkeinen
Date: Thu May 08 2014 - 06:55:47 EST


On 23/04/14 17:35, Masami Ichikawa wrote:
> kmemleak reported a memory leak as below.
>
> unreferenced object 0xffff8800dab6d8d8 (size 96):
> comm "swapper/0", pid 1, jiffies 4294877598 (age 38.483s)
> hex dump (first 32 bytes):
> 00 00 00 00 00 01 00 00 08 00 00 00 10 00 00 00 ................
> 07 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00 ................
> backtrace:
> [<ffffffff814e8f2e>] kmemleak_alloc+0x4e/0xb0
> [<ffffffff811a0600>] __kmalloc+0x280/0x320
> [<ffffffff81309b61>] soft_cursor+0x231/0x290
> [<ffffffff81309393>] bit_cursor+0x613/0x650
> [<ffffffff8130556b>] fbcon_cursor+0x13b/0x1c0
> [<ffffffff813755f8>] hide_cursor+0x28/0xa0
> [<ffffffff81376e98>] redraw_screen+0x168/0x240
> [<ffffffff81303891>] fbcon_prepare_logo+0x381/0x420
> [<ffffffff81303c7e>] fbcon_init+0x34e/0x590
> [<ffffffff81375828>] visual_init+0xb8/0x120
> [<ffffffff81377c93>] do_bind_con_driver+0x163/0x380
> [<ffffffff81378494>] do_take_over_console+0x114/0x1c0
> [<ffffffff81303f23>] do_fbcon_takeover+0x63/0xd0
> [<ffffffff813086dd>] fbcon_event_notify+0x68d/0x7e0
> [<ffffffff814ff7ac>] notifier_call_chain+0x4c/0x70
> [<ffffffff8108c85d>] __blocking_notifier_call_chain+0x4d/0x70
>
> This memory leak cause is, fbcon_ops's cursor_src is allocated in
> soft_cursor() but not released in con2fb_release_oldinfo().
> so, cursor_src is needed to be released when oldinfo is going to be
> released.
>
> Signed-off-by: Masami Ichikawa <masami256@xxxxxxxxx>
> ---
> drivers/video/console/fbcon.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/video/console/fbcon.c b/drivers/video/console/fbcon.c
> index f447734..57b1d44 100644
> --- a/drivers/video/console/fbcon.c
> +++ b/drivers/video/console/fbcon.c
> @@ -748,6 +748,7 @@ static int con2fb_release_oldinfo(struct vc_data *vc, struct fb_info *oldinfo,
> fbcon_del_cursor_timer(oldinfo);
> kfree(ops->cursor_state.mask);
> kfree(ops->cursor_data);
> + kfree(ops->cursor_src);
> kfree(ops->fontbuffer);
> kfree(oldinfo->fbcon_par);
> oldinfo->fbcon_par = NULL;
>

Thanks, queued for 3.16.

Tomi


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